JP4485419B2 - Electrostatic latent image carrier, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

  The present invention is an electrostatic latent image carrier (“photosensitive member”, “electrophotographic photosensitive member”) having a photosensitive layer that has high abrasion resistance and scratch resistance, is less susceptible to cracking and film peeling, and has good electrical characteristics. And an image forming method, an image forming apparatus, and a process cartridge that use the electrostatic latent image carrier and have high durability and can realize high image quality over a long period of time.

  In recent years, in order to write digital signal processed data, an electrophotographic image forming method in which an electrostatic latent image is formed by exposing to light on an organic photoreceptor and an image is formed by a reversal development method has been actively performed. became.

  An organic photoreceptor used in such a system is required to be stable over a long period of use and be compatible with writing at a high resolution. Therefore, improvement in durability of the photoreceptor has been demanded. However, the disadvantages of organic photoreceptors are weak in strength, and defects due to wear and scratches on the photosensitive layer are likely to occur, and improvements have been demanded in terms of durability.

  Examples of techniques for improving the abrasion resistance of the photosensitive layer include (1) using a curable binder in the crosslinkable charge transport layer (see Patent Document 1), and (2) using a polymer charge transport material. Proposed (see Patent Document 2), (3) a cross-linked charge transport layer in which an inorganic filler is dispersed (see Patent Document 3), and the like.

  Among these techniques, those using the curable binder (1) have poor compatibility with the charge transport material, and the residual potential increases due to impurities such as polymerization initiators and unreacted residues. There is a tendency for the reduction to occur easily. In addition, the use of the polymer type charge transport material (2) can improve the abrasion resistance to some extent, but has yet to fully satisfy the durability required for the organic photoreceptor. Not in. In addition, since polymer charge transport materials are difficult to polymerize and purify, and it is difficult to obtain high-purity materials, it is difficult to stabilize electrical characteristics. In addition, there are problems in production such as high viscosity of the coating liquid. The dispersion of the inorganic filler of (3) exhibits higher abrasion resistance than a photoreceptor in which a normal low molecular charge transport material is dispersed in an inert polymer, but is present on the surface of the inorganic filler. Due to the charge trapping, the residual potential rises and the image density tends to decrease. In addition, when the unevenness of the inorganic filler and the binder resin on the surface of the photoconductor is large, a cleaning failure may occur, which may cause toner filming and image flow. (1), (2), and ( The technique 3) has not yet satisfied the overall durability including the electrical durability and mechanical durability required for the organic photoreceptor.

  Furthermore, in order to improve the abrasion resistance and scratch resistance of (1) above, a photoreceptor containing a polyfunctional acrylate monomer cured product has been proposed (see Patent Document 4). However, in this photoreceptor, although there is a description that the protective layer provided on the photosensitive layer contains a polyfunctional acrylate monomer cured product, the protective layer may contain a charge transport material. However, when the low-molecular charge transport material is simply contained in the cross-linked charge transport layer, there is a problem of compatibility with the cured product. As a result, precipitation of a low-molecular charge transport material and white turbidity occur, and not only the image density is lowered but also the mechanical strength is lowered due to the increase of the exposed portion potential. In addition, the proposed photoreceptor specifically reacts with a monomer in a state containing a polymer binder, so that the three-dimensional network structure does not proceed sufficiently, and the cross-linking density becomes dilute. It has not yet reached the point where it is possible to exhibit excellent wear resistance.

  As a technique for improving the abrasion resistance of the photosensitive layer instead of these, for example, a coating solution comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin It has been proposed to provide a charge transport layer formed by using (see Patent Document 5). This proposed binder resin is considered to play a role in improving the adhesion between the charge generation layer and the curable charge transport layer, and further relaxing the internal stress of the film during thick film curing. And having reactivity with respect to the charge transfer agent and those not having the double bond and not having reactivity. This photoconductor is remarkably compatible with both wear resistance and good electrical properties. However, when a non-reactive binder resin is used, the binder resin, the monomer, and the charge transport agent are used. May be poorly compatible with the cured product generated by the reaction with the resin, and phase separation may occur in the cross-linked charge transport layer, which may cause flaws and adhesion of external additives and paper powder in the toner. In addition, as described above, the three-dimensional network structure does not proceed sufficiently and the cross-linking density becomes dilute, so that it has not reached the point where dramatic wear resistance can be exhibited. In addition, what is specifically described as the monomer used in this photoreceptor is bifunctional, and from these reasons, it has not yet been satisfactory in terms of wear resistance. Even when a reactive binder is used, the molecular weight of the cured product is increased, but the number of intermolecular crosslinks is small. Abrasion was not sufficient.

In addition, a photoreceptor having a photosensitive layer containing a compound obtained by curing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule has been proposed (see Patent Document 6). This photosensitive layer has high hardness because the crosslink density can be increased, but since the bulky hole transporting compound has two or more chain polymerizable functional groups, distortion occurs in the cured product and internal stress increases. In some cases, the crosslinked surface layer is liable to crack or peel off when used for a long period of time.
In order to improve wear resistance, it has been put into practical use to provide a photosensitive layer or a surface protective layer containing a highly durable organosilicon binder resin. However, the organosilicon binder easily absorbs moisture, resulting in degradation of image quality, particularly image blur due to filming and image flow.

On the other hand, as one of the required items for the image forming system, there is an increase in the speed of the image forming process for high-speed printing and copying. As the speed of the system increases, the photoreceptor is required to respond at high speed to the charging, exposure, development, transfer, and cleaning processes that are components of the system. Furthermore, since it contacts and contacts with the contact parts, such as the primary charger, the developing device, the transfer charger, and the cleaning device, which are the components, at high speed, its strength and durability are also required. In addition, many characteristics are required, such as an increase in the chance of contact with chemical substances such as ozone and NOx generated from the charger, and the need for recoverability that the same part is repeatedly used in a short time.
In this case, in particular, an image forming system represented by a laser beam printer or a copying machine does not use the components alone, but uses all the components arranged around the photoreceptor. It is established for the first time as one system, and is installed in one device, that is, located in one box. For this reason, the environment and atmosphere inside the apparatus are special conditions although they are affected by the environment and atmosphere outside the apparatus. For example, charging of the photosensitive member in the image forming process may be performed by applying a high voltage to a charger wire or the like to discharge by corona discharge (corona charging), or by using a rubber blade or roller elastic body on the surface of the photosensitive member. A method of contact charging and charging by applying to the elastic body (contact charging) is widely used, but each method has some difference in amount, but it involves generation of ozone and NOx with discharge. . These products are known to modify or deteriorate the composition of the surface layer of the photoreceptor, and the atmosphere in the image forming apparatus differs from the general normal atmosphere outside the apparatus depending on these products. Come. In the image forming apparatus, the toner image developed on the photoconductor is transferred to a transfer material such as paper or a belt in a transfer process, and the transfer material contacts the photoconductor at that time. In the contact, adhesion of substances such as talc, fibers, surface modifiers, and the like filled in the transfer material is likely to occur, and the surface of the photoreceptor is modified to promote deterioration. Furthermore, the toner image transferred to paper, film or the like proceeds to the fixing step. Usually, the fixing device is installed in the same device (box) and is heated to about 100 to 200 ° C. Consists of heat-generating parts and a pressure device. Part of the heat generated from the fixing device is discharged outside the device by an exhaust fan or the like, but remains in the image forming device (box). It becomes a high temperature atmosphere.

  Further, when a scanner or the like for reading an image is equipped, the influence of heat generation from the reading light source is not limited. As described above, the temperature inside the image forming apparatus is more easily raised than that outside the apparatus, and by raising the temperature, the fluidity of the developer (toner) decreases, the cleaning property changes, the charging of the charger Due to changes in capacity, contact area with the photoconductor surface, contact pressure, friction coefficient, and wear of the surface layer, blade vibration, etc. occur, so the ambient temperature is optimized with exhaust fans, exhaust ducts, etc. . However, considering the future demands for downsizing and cost reduction of the image forming apparatus, there are limitations on the installation of the exhaust fan and the exhaust duct. That is, a material used for an image forming apparatus (especially when used in a high-speed image forming process) needs to exhibit good characteristics even under such conditions. Even if it is excellent in strength when evaluated in the environment and atmosphere, it is different from the conditions in the actual image forming apparatus used in the market. In this evaluation, it is possible to determine the basic characteristics of the material alone. However, it is not sufficient for the original selection in an actual image forming system.

  For example, even if the evaluation by the Taber abrasion test is good, the wear resistance is not always good in an actual image forming apparatus. For example, in Patent Document 7, wear resistance is determined by a Taber abrasion test using a CS-10F wear wheel, and as a result, an electrophotographic photoreceptor excellent in durability is obtained. In the image forming apparatus, various conditions are involved to change the durability and stability of the photoreceptor. Especially in image forming apparatuses that have a high-speed process and image forming apparatuses that are limited in exhaust devices, the temperature, gas phase components, etc. are greatly different. A carrier is not obtained.

  Further, in Patent Document 8, such a problem can be solved by using a specific polyarylate resin for the surface layer, but the effect is largely due to an increase in molecular weight, and by changing to a polyarylate resin However, it is insufficient for future demands that require high speed and high durability.

  Therefore, an electrostatic latent image carrier having a photosensitive layer that has high abrasion resistance and scratch resistance, is less likely to cause cracks and film peeling, and has good electrical characteristics, and uses the electrostatic latent image carrier and is highly durable. However, there is no image forming method and related technology capable of realizing high image quality that can be sufficiently satisfied over a long period of time, and the rapid development thereof is desired.

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A Japanese Patent Laid-Open No. 10-288846 JP 2002-72510 A

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is an electrostatic latent image that has high scratch resistance and abrasion resistance, does not decrease surface resistance in a high humidity environment, is highly durable over a long period of time, and can provide a high-quality image. It is an object of the present invention to provide a carrier, an image forming method using the electrostatic latent image carrier, an image forming apparatus, and a process cartridge.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, the heat generation from the drive motor, the heat capacity of the fixing device, the exhaustion due to the downsizing of the device, and the like due to the future speedup of the image forming apparatus As the number of fans and exhaust ducts is reduced, the inside of the image forming apparatus tends to be in a high temperature atmosphere. In addition, ozone, nitrogen oxide (NOx) generated in the charging process of the image forming process, charged particles generated in a contact or non-contact roller charger, and active oxygen cause deterioration of the surface of the photoreceptor in a high temperature atmosphere. It becomes easy. In particular, in systems where the process speed of the electrophotographic process indicated by the rotational speed of the photoconductor exceeds 200 mm / sec, the amount of heat generated increases due to the large torque of the motor and the high heat capacity of the fixing device. Since it is easy to generate frictional heat by contacting the members of the electrophotographic process (charging to cleaning), it is necessary to design a photoconductor that is optimized according to the conditions and atmosphere used, and also the surface layer. I found out.

  Further, in the present invention, when the actual inside of the image forming apparatus for which the next-generation high-speed and downsizing as described above is being studied, the atmospheric temperature becomes 40 ° C. or more, and further, ozone, NOx. It was found that there are relatively many etc. In the conventional apparatus, the process speed of the apparatus is low, the exhaust / ventilation is good, and the conditions are relatively normal living environment / atmosphere (temperature, ozone, NOx concentration, humidity, etc.). It was close. The ambient temperature (room temperature) in which the image forming apparatus in the present invention is placed indicates the temperature of a space in which an apparatus using an image forming process represented by a copying machine or a laser beam printer is placed, The maximum temperature of the environment that can be used by normal human beings was 35 ° C or lower. In addition, the ambient temperature (in-machine temperature) around the electrophotographic photosensitive member when the image forming apparatus is in operation is achieved by increasing the temperature inside the apparatus due to the heat generation part of the apparatus when the apparatus is operated. It has been found that the temperature is shown and not the temperature achieved by increasing the ambient temperature (room temperature) etc. in which the apparatus is placed.

The present invention is based on the above findings of the present inventors, and means for solving the above problems are as follows. That is,
<1> An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, a developing step of developing the electrostatic latent image with toner to form a visible image, A transfer step of transferring a visible image to a recording medium, a fixing step of fixing the transfer image transferred to the recording medium, and a cleaning step of cleaning the electrostatic latent image carrier,
The electrostatic latent image carrier has a support and a photosensitive layer formed by laminating at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer in this order on the support, An electrostatic latent image carrier in which a crosslinkable charge transport layer contains a reaction product of a tri- or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. And
The electrostatic latent image carrier is used by being mounted on an image forming apparatus having an ambient temperature of 40 ° C. or lower and an ambient temperature around the electrostatic latent image carrier in operation exceeding 40 ° C .;
The charge-transporting trifunctional or more radical polymerizable compound having no structure is an image forming method, comprising Rukoto used two or more kinds.
<2> The image forming method according to <1>, which is used in an image forming apparatus having a process speed of 200 mm / sec or more.
<3> The image forming method according to any one of <1> to <2>, wherein the cross-linked charge transport layer has a thickness of 1 to 10 μm.
<4> The image forming method according to any one of <1> to <3>, wherein the cross-linked charge transport layer has a thickness of 2 to 8 μm.
<5> The above <1> to <4>, wherein the radical polymerizable functional group in the trifunctional or higher functional radical polymerizable compound and the monofunctional radical polymerizable compound is at least one of an acryloyloxy group and a methacryloyloxy group An image forming method as described above.
<6> The above-described image forming method used to charge the surface of the latent electrostatic image bearing member by applying a direct current voltage on which the alternating current is superimposed by a charger arranged in contact or non-contact with the surface of the latent electrostatic image bearing member. The image forming method according to any one of <1> to <5> .

  The electrostatic latent image carrier of the present invention comprises a support, and a photosensitive layer formed by laminating at least a charge generation layer, a charge transport layer, and a crosslinked charge transport layer in this order on the support. An electrostatic latent image carrier comprising a reaction product of a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure in the cross-linked charge transport layer The electrostatic latent image carrier is mounted and used in an image forming apparatus having an ambient temperature of 40 ° C. or lower and an ambient temperature around the electrostatic latent image carrier in operation exceeds 40 ° C. . The electrostatic latent image bearing member of the present invention has high scratch resistance, high wear resistance, does not decrease surface resistance in a high humidity environment, and also has a long period of time in a high temperature environment such as a high-speed process. High durability and high quality images can be obtained.

  The electrostatic latent image carrier (electrophotographic photosensitive member) is used in an environment where a series of processes such as a charging unit, a developing unit, a transfer unit, a fixing unit, a cleaning unit, and a discharging unit are repeated. Wears or scratches cause image degradation and a lifespan. Factors that cause this wear and scratch are (1) charging, decomposition of the photoreceptor surface composition due to discharge during static elimination and chemical degradation due to oxidizing gas, (2) carrier adhesion during development, (3) during transfer (4) Friction with cleaning brush, cleaning blade and intervening toner or adhering carrier during cleaning. In order to design a photoreceptor that is resistant to these hazards, it is important to make the surface layer highly hard, highly elastic and uniform, and a method of forming a dense and homogeneous three-dimensional network structure from the film structure Is promising. The cross-linked charge transport layer corresponding to the surface of the present invention has a cross-linked structure obtained by curing a tri- or higher-functional radical polymerizable monomer, so that a three-dimensional network structure is developed, and the cross-link density is very high and the hardness is high and the elastic surface layer is high. High abrasion resistance and scratch resistance are achieved. Thus, it is important to increase the crosslink density on the surface of the photoreceptor, that is, the number of crosslink bonds per unit volume. However, since a large number of bonds are instantaneously formed in the curing reaction, internal stress due to volume shrinkage occurs. Since this internal stress increases as the thickness of the cross-linked layer increases, cracks and film peeling tend to occur when the entire charge transport layer is cured. Even if this phenomenon does not appear initially, it may be likely to occur over time due to repeated use in the electrophotographic process and the influence of charging, development, transfer, cleaning hazards and thermal fluctuations. Methods for solving such problems include (1) introducing a polymer component into the crosslinked layer and the crosslinked structure, (2) using a large amount of monofunctional and bifunctional radically polymerizable monomers, and (3) flexible groups. Although the directionality which softens the cured resin layer, such as using a polyfunctional monomer which has, is mentioned, in any case, the crosslinking density of the crosslinked layer becomes dilute, and the dramatic wear resistance is not achieved.

  In contrast, the latent electrostatic image bearing member (photoreceptor) of the present invention is provided with a cross-linked charge transport layer having a high cross-link density and having a three-dimensional network structure formed on the charge transport layer in a thickness of 1 to 10 μm. Thus, the above-described cracks and film peeling do not occur, and very high wear resistance is achieved. The reason why the photoconductor of the present invention can suppress cracking and film peeling is that the cross-linked charge transport layer can be made thin, so that the internal stress does not increase, and since the charge transport layer is provided in the lower layer, the surface of the cross-linked charge transport layer This is because internal stress can be relaxed. For this reason, it is not necessary to contain a large amount of polymer material in the cross-linked charge transport layer, and the polymer material and radical polymerizable composition (radical polymerizable monomer or radical polymerizable compound having a charge transport structure) generated at this time. Scratches and toner filming due to incompatibility with the cured product resulting from this reaction are unlikely to occur. Furthermore, when a thick film over the entire charge transport layer is cured by light energy irradiation, light transmission from the absorption by the charge transport structure to the inside is limited, and a phenomenon in which the curing reaction does not proceed sufficiently may occur. In the cross-linked charge transport layer of the present invention, the curing reaction proceeds uniformly from the surface to the inside of 8 μm or less, and high wear resistance is maintained inside as well as the surface. In addition, in the formation of the outermost surface layer of the present invention, in addition to the trifunctional radical polymerizable monomer, a radical polymerizable compound having a monofunctional charge transporting structure is further contained, which is a trifunctional or higher functional group. It is taken into the crosslinked structure when the radical polymerizable monomer is cured. On the other hand, when a low molecular charge transport material having no functional group is contained in the cross-linked surface layer, precipitation of the low molecular charge transport material and white turbidity occur due to its low compatibility, and the cross-linked surface layer The mechanical strength also decreases. On the other hand, when a bifunctional or higher-functional charge transporting compound is used as the main component, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased. Becomes very large, which increases the internal stress of the cross-linked charge transport layer.

  Furthermore, the electrostatic latent image carrier of the present invention has good electrical characteristics, and thus high image quality is realized over a long period of time. This is because a radically polymerizable compound having a monofunctional charge transporting structure is used as a constituent material of the crosslinkable charge transport layer and is immobilized in a pendant shape between the crosslinks. As described above, the charge transport material having no functional group causes precipitation and clouding phenomenon, and the electrical characteristics are remarkably deteriorated in repeated use such as reduction in sensitivity and increase in residual potential. When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with a plurality of bonds, so the intermediate structure (cation radical) during charge transport cannot be kept stable, Sensitivity decreases due to traps and residual potential increases. Such deterioration of the electrical characteristics appears as an image such as a decrease in image density and thinning of characters. Furthermore, in the latent electrostatic image bearing member of the present invention, a high mobility design with less charge trapping of the conventional photoreceptor can be applied as the lower charge transport layer, and the electrical side effects of the cross-linked charge transport layer can be minimized. Can be suppressed.

  The cross-linked charge transport layer is formed by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure, and the entire layer is three-dimensional. The network structure is developed and has a high crosslinking density, but contains other than the above components (for example, mono- or bifunctional monomers, polymer binders, antioxidants, leveling agents, plasticizers and other additives and dissolution from the lower layer) Depending on mixing components) and curing conditions, the cross-linking density may be locally dilute or may be formed as an aggregate of minute cured products cross-linked with high density. Such a cross-linked charge transport layer has low bonding strength between cured products, is soluble in organic solvents, and is repeatedly used in the electrophotographic process. Elimination is likely to occur. By making the cross-linkable charge transport layer insoluble in an organic solvent as in the present invention, the original three-dimensional network structure is developed and has a high degree of cross-linking, and the chain reaction proceeds in a wide range to obtain a cured product. Since the polymer has a high molecular weight, dramatic wear resistance is achieved.

  An image forming apparatus according to the present invention includes an electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image using toner. Developing means for developing a visible image by development, transfer means for transferring the visible image to a recording medium, fixing means for fixing the transfer image transferred to the recording medium, and the electrostatic latent image carrier The electrostatic latent image carrier is the electrostatic latent image carrier of the present invention. In the image forming apparatus of the present invention, since the electrostatic latent image carrier of the present invention is used as the electrostatic latent image carrier, the surface resistance is high in a high humidity environment with high scratch resistance and wear resistance. It does not decrease, and an image with high durability and high image quality can be obtained over a long period of time even in a high temperature environment seen in a high-speed process or the like.

  The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, and developing the electrostatic latent image with toner to form a visible image. At least a developing step, a transferring step for transferring the visible image to a recording medium, a fixing step for fixing the transferred image transferred to the recording medium, and a cleaning step for cleaning the electrostatic latent image carrier. The electrostatic latent image carrier is the electrostatic latent image carrier of the present invention. In the image forming method of the present invention, since the electrostatic latent image carrier of the present invention is used as the electrostatic latent image carrier, the surface resistance is high in a high humidity environment with high scratch resistance and abrasion resistance. In addition, the image can be formed with high durability and high image quality over a long period of time even in a high temperature environment seen in a high-speed process or the like.

  The process cartridge of the present invention has at least an electrostatic latent image carrier and developing means for developing a latent image formed on the electrostatic latent image carrier using toner to form a visible image. Since the electrostatic latent image carrier of the present invention is used as the electrostatic latent image carrier, scratch resistance, high wear resistance, surface resistance does not decrease in a high humidity environment, In addition, high durability and high-quality images can be obtained over a long period of time even in high-temperature environments found in high-speed processes, etc., and even when blade cleaning or the like is performed, the wear of the electrostatic latent image carrier is extremely slightly suppressed. The property is also good.

According to the present invention, conventional problems can be solved, and an actual image can be obtained by using an electrostatic latent image carrier having a cross-linked charge transport layer as a surface layer when used under specific conditions in a high-temperature atmosphere. Also in the forming apparatus, it is possible to provide an electrostatic latent image carrier that has good wear resistance and does not deteriorate wear resistance.
In addition, the electrostatic latent image carrier of the present invention exhibits good wear resistance even in a system with a process speed exceeding 200 mm / sec, and is disposed in contact or non-contact with the surface of the electrostatic latent image carrier. It exhibits excellent wear resistance in the process of charging the latent electrostatic image bearing member by applying a DC voltage superimposed with alternating current from the charged charger and the process using a blade cleaning method, and is extremely durable and practical. It is a thing.

(Electrostatic latent image carrier)
The electrostatic latent image carrier of the present invention comprises a support, and a photosensitive layer formed by laminating at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer in this order on the support. Furthermore, it has other layers as required.
As will be described later, the electrostatic latent image carrier has an ambient temperature of 40 ° C. or lower, and is mounted and used in an image forming apparatus in which the ambient temperature around the electrostatic latent image carrier exceeds 40 ° C. during operation. It is done.

  Here, FIG. 1 is a schematic sectional view showing an example of the electrostatic latent image carrier (electrophotographic photosensitive member) of the present invention. In this electrostatic latent image carrier, a charge generation layer 2 having a charge generation function, a charge transport layer 3 having a charge transport material function, and a cross-linked charge transport layer 4 are laminated on a conductive support 1 in this order. This is a photoreceptor having a laminated structure.

-Support-
The support is not particularly limited as long as it has a volume resistance of 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. For example, aluminum, nickel, chromium, nichrome, copper Metals such as gold, silver and platinum; metal oxides such as tin oxide and indium oxide, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. And a tube subjected to surface treatment such as cutting, super-finishing, polishing, etc. can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as a support.

In addition, those obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the support of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Etc. The binder resin used at the same time includes polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate. Copolymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole, Thermoplastic, thermosetting resin, or photocurable resin such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like can be given.
The conductive layer can be provided by dispersing and applying these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene and the like.

  Furthermore, it is electrically conductive by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

-Photosensitive layer-
The photosensitive layer is formed by laminating a charge generation layer having a charge generation function, a charge transport layer having a charge transport material function, and a crosslinked charge transport layer in this order, and further having other layers as necessary. Become.

-Charge generation layer-
The charge generation layer contains a charge generation material having a charge generation function as a main component, a binder resin, and further contains other components as necessary.

As the charge generation material, both inorganic materials and organic materials can be suitably used.
Examples of the inorganic material include crystalline selenium, amorphous-selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, and amorphous-silicon. In the amorphous-silicon, those obtained by terminating dangling bonds with hydrogen atoms or halogen atoms, or those doped with boron atoms, phosphorus atoms or the like are preferably used.
A known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigo Id based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.
Among these, oxytitanium phthalocyanine represented by the following structural formula (1) is one of the preferable ones.

In the structural formula (1), X ¹ , X ² , X ³ , and X ⁴ represent Cl or Br. h, i, j, and k represent an integer of 0 to 4.

  The crystal form of the oxytitanium phthalocyanine is not particularly limited and may be appropriately selected depending on the intended purpose. The black angle (2θ ± 0.2 °) in the characteristic X-ray diffraction of CuKα is 9.0 °, Sensitivity is either oxytitanium phthalocyanine having strong peaks at 14.2 °, 23.9 ° and 27.1 °, or oxytitanium phthalocyanine having strong peaks at 9.6 ° and 27.3 °. It is more preferable from the viewpoint of characteristics.

Examples of the binder resin include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and the like. . These can be used alone or as a mixture of two or more.
Specifically, JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP-A-01-241559, JP-A-04-011627. JP, 04-175337, JP 04-183719, JP 04-22514, JP 04-230767, JP 04-320420, 05-232727. JP, 05-310904, JP 06-234836, JP 06-234837, JP 06-234838, JP 06-234839, JP 06-234840, Japanese Laid-Open Patent Application Nos. 06-234841, 06-239049, 06-2 JP 6050, JP 06-236051, JP 06-295077, JP 07-056374, JP 08-176293, JP 08-208820, JP 08-21640. JP-A-08-253568, JP-A-08-269183, JP-A-09-062019, JP-A-09-043883, JP-A-09-71642, JP-A-09-87376, JP-A 09-104746, JP-A 09-110974, JP-A 09-110976, JP-A 09-157378, JP-A 09-221544, JP-A 09-227669, JP 09-235367, JP 09-241369 A, JP 09-09 A 68226, JP-A No. 09-272735, JP-A No. 09-302084, JP-A No. 09-302085 discloses a charge transport polymer material described in JP-A 09-328539 discloses the like.

In addition to the binder resin, a polymer charge transport material having a charge transport function, such as polycarbonate, polyester, polyurethane, polyether having arylamine skeleton, benzidine skeleton, hydrazone skeleton, carbazole skeleton, stilbene skeleton, pyrazoline skeleton, etc. A polymer material such as polysiloxane or acrylic resin, a polymer material having a polysilane skeleton, or the like can be used.
Specific examples include polysilylene polymers described in JP-A-63-285552, JP-A-05-19497, JP-A-05-70595, JP-A-10-73944, and the like.

The charge generation layer may contain a low molecular charge transport material. As the low molecular charge transport material, both a hole transport material and an electron transport material are suitable.
As the electron transporting material, an electron accepting material is preferable. For example, chloranil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5, 7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene 4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives, and the like. These can be used individually by 1 type or in mixture of 2 or more types.
Suitable examples of the hole transporting material include the electron donating materials shown below, for example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, Stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives , Enamine derivatives, and the like. These hole transport materials can be used alone or as a mixture of two or more.

The method for forming the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a vacuum thin film preparation method and a casting method from a solution dispersion system.
As the vacuum thin film production method, for example, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, and the like are suitable. Can be formed satisfactorily.
As a method of providing a charge generation layer by the casting method, for example, the inorganic or organic charge generation material is dispersed by a ball mill, an attritor, a sand mill, a bead mill or the like using a solvent together with a binder resin as necessary, The dispersion can be formed by appropriately diluting and applying. Examples of the solvent include tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclopentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, and the like. In addition, a leveling agent such as dimethyl silicone oil or methylphenyl silicone oil can be added to the dispersion as necessary. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

  The thickness of the charge generation layer is preferably from 0.01 to 5 μm, more preferably from 0.05 to 2 μm.

-Charge transport layer-
The charge transport layer is a layer having a charge transport function, and a charge transport material having a charge transport function and a binder resin are dissolved or dispersed in an appropriate solvent, and this is applied onto the charge generation layer and dried. Let it form.
As the charge transport material, the electron transport material, hole transport material and polymer charge transport material described in the charge generation layer can be used. As described above, the use of the polymer charge transport material can reduce the solubility of the lower layer when the cross-linked charge transport layer is applied, and is particularly useful.

  Examples of the binder resin include polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer. Coalescence, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole resin, acrylic resin, A silicone resin, an epoxy resin, a melamine resin, a urethane resin, a phenol resin, an alkyd resin, etc. are mentioned, These may be used individually by 1 type and may use 2 or more types together.

  The amount of the charge transport material added is preferably 20 to 300 parts by weight, and more preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it can be used alone or in combination with a binder resin.

  As the solvent used for coating the charge transport layer, the same solvent as the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. In addition, the same coating method as that for the charge generation layer can be used to form the lower layer portion of the charge transport layer.

Moreover, a plasticizer and a leveling agent can be added to the charge transport layer as necessary.
As said plasticizer, what is used as a plasticizer of resin generally used, such as dibutyl phthalate and dioctyl phthalate, can be used. The amount of the plasticizer used is suitably about 0 to 30 parts by mass with respect to 100 parts by mass of the binder resin.
Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The amount of the leveling agent used is preferably about 0 to 1 part by mass with respect to 100 parts by mass of the binder resin.

  There is no restriction | limiting in particular in the thickness of the said charge transport layer, According to the objective, it can select suitably, 5-40 micrometers is preferable and 10-30 micrometers is more preferable.

--Cross-linked charge transport layer--
On the charge transport layer, a cross-linkable charge transport layer coating liquid described later is applied, and after drying as necessary, a curing reaction is started by external energy of heat or light irradiation to form a cross-linkable charge transport layer. .
The crosslinkable charge transport layer is a layer having a crosslink structure having a charge transport function, and having at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable having a monofunctional charge transport structure. The compound is formed by dissolving or dispersing the compound in a suitable solvent, and applying and drying it on the charge transport layer.

  Examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting property include hole transporting structures such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. The monomer which does not have electron transport structures, such as an electron withdrawing aromatic ring which has, and has 3 or more radically polymerizable functional groups. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) As the 1-substituted ethylene functional group, for example, a functional group represented by the following structural formula (2) is preferably exemplified.
^{_{CH 2 = CH-X 1 -}} ··· structural formula (2)
However, in the structural formula (2), X ¹ represents an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, —COO— group, —CON (R ¹⁰ ) — group (where R ¹⁰ is a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, an aralkyl group such as a benzyl group, a naphthylmethyl group or a phenethyl group, a phenyl group, Represents an aryl group such as a naphthyl group) or an S-group.
Specific examples of these substituents include vinyl, styryl, 2-methyl-1,3-butadienyl, vinylcarbonyl, acryloyloxy, acryloylamide, and vinylthioether groups.

(2) As the 1,1-substituted ethylene functional group, for example, a functional group represented by the following structural formula (3) is preferably exemplified.
^{_{CH 2 = C (Y) -X}} 2 - ···· structural formula (3)
However, in the structural formula (3), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or naphthyl. An aryl group such as a group, an alkoxy group such as a halogen atom, a cyano group, a nitro group, a methoxy group or an ethoxy group, a —COOR ¹¹ group (where R ¹¹ is a hydrogen atom, a methyl group optionally having a substituent) , An alkyl group such as an ethyl group, an optionally substituted benzyl, an aralkyl group such as a phenethyl group, an optionally substituted phenyl group, an aryl group such as a naphthyl group, or CONR ¹² R ¹³ (wherein, R ¹² and R ¹³ are hydrogen atoms, which may have a substituent an alkyl group such as methyl group and ethyl group, which may have a substituent group benzyl group, naphthylmethyl group, there have Aralkyl group, or a substituent a phenyl group which may have a phenetyl group, an aryl group such as a naphthyl group, may be the same or different from each other.) Further, X ² is the structural formula (2 ) Represents the same substituent, single bond, and alkylene group as X ^1. However, at least one of Y and X ² is an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring.
Examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group. Etc.
In addition, examples of the substituent further substituted with the substituent for X and Y include an alkyl group such as a halogen atom, a nitro group, a cyano group, a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, An aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, an aralkyl group such as a benzyl group and a phenethyl group, and the like.
Among these radical polymerizable functional groups, an acryloyloxy group and a methacryloyloxy group are particularly useful, and a compound having three or more acryloyloxy groups includes, for example, a compound having three or more hydroxyl groups in the molecule. It can be obtained by an ester reaction or a transesterification reaction using acrylic acid (salt), acrylic acid halide, and acrylic acid ester. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
Examples of the radical polymerizable monomer include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter referred to as EO-modified) triacrylate, and triacrylate. Methylolpropylenepropyleneoxy modified (hereinafter referred to as EO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epi Chlorohydrin modified (hereinafter referred to as ECH modified) triacryle Glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated di Pentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2, 2, 5, 5 , -Tetrahydroxymethylcyclopentanone tetraacrylate, etc. Gerare, these may be used alone or in combination of two or more thereof.

Moreover, as the trifunctional or higher functional radical polymerizable compound having no charge transporting structure, a compound represented by the following structural formula (i) is preferably exemplified.
In addition, the trifunctional or higher-functional radical polymerizable compound having no charge transporting structure includes a plurality of radical polymerizable compounds having different structures, and at least one of the radical polymerizable compounds is represented by the following general formula ( It is preferable that it is a compound represented by i).
However, in the structural formula (i), R ₇₁ , R ₇₂ , R ₇₃ , R ₇₄ , R ₇₅ , and R ₇₆ may be the same as or different from each other, a hydrogen atom, or The group represented by Structural Formula (ii) is represented. Two or more of R _{71 to} R ₇₆ are not hydrogen atoms at the same time.
However, in the structural formula (ii), R ₇₇ represents a single bond, an alkylene group, an alkylene ether group, or an alkyleneoxycarbonyl group. R ₇₈ represents a hydrogen atom or a methyl group.
Examples of the alkylene group, alkylene ether group, and alkyleneoxycarbonyl group include those similar to Z in Structural Formulas (4) and (5) described later.

When the radically polymerizable compound represented by the structural formula (i) is used, a three-dimensional network structure is further developed and the degree of crosslinking is much higher than when a trifunctional or tetrafunctional compound is used. A high hardness cross-linked surface layer is obtained, and high wear resistance is achieved. Moreover, the compatibility with the monofunctional radically polymerizable compound having the charge transporting structure of the present invention is also good, and these are simultaneously cured in a short time, and a smooth surface layer can be formed by improving the curing rate. Thus, the effects of the present invention can be further improved.
Furthermore, a radically polymerizable monomer having no charge transporting structure represented by the structural formula (i) and a monofunctional radically polymerizable compound having a charge transporting structure, which has many reactive functional groups and a high curing rate, are cured. This makes it possible to form a uniform crosslinked film with less distortion in the crosslinked layer. As a result, the unreacted portion of the charge transport material is reduced in the crosslinked surface layer, and the homogeneity inside the crosslinked film is greatly improved. Is done. As a result, it is possible to achieve both of improved wear resistance and stable electrostatic characteristics.

  As the compound represented by the structural formula (i), a compound having 5 or more acryloyloxy groups includes, for example, a compound having 5 or more hydroxyl groups in the molecule, acrylic acid (salt), acrylic acid halide, acrylic It can be obtained by an ester reaction or an ester exchange reaction using an acid ester. A compound having 5 or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having 5 or more radical polymerizable functional groups may be the same or different.

  The radical polymerizable monomer having no charge transporting structure represented by the structural formula (i) includes a compound having three acryloyloxy groups and three hydrogen groups, four acryloyloxy groups and two hydrogen groups. A compound having 5 acryloyloxy groups and one hydrogen group, a compound having 6 acryloyloxy groups, a compound having 3 methacryloyloxy groups and 3 hydrogen groups, and 4 methacryloyl Examples include compounds having an oxy group and two hydrogen groups, compounds having five methacryloyloxy groups and one hydrogen group, compounds having six methacryloyloxy groups, and the like. The compounds represented are exemplified, but are not limited to these compounds. These may be used alone or in combination of two or more.

These monomers can be produced by esterification of polyhydric alcohols for reasons such as high yield, low production cost and high productivity. These monomers can be used in two or more types, more specifically two types. When three or four types are used in combination and a monomer having six radical polymerizable functional groups is used, it has six radical polymerizable functional groups by esterification in that the yield is excellent. It is preferable to use a mixture of a monomer and a monomer having 5 or less radical polymerizable functional groups in which hydrogen groups remain without being esterified. Moreover, it is preferable that the compounding rate contains 20-99 mass% of this monomer similarly at the point that a yield is excellent, 30-97 mass% is more preferable, 40-95 mass% is still more preferable.
(1) For the same reason, when using a monomer having five radical polymerizable functional groups, it is preferable to contain 20 to 99% by mass of this monomer, more preferably 30 to 97% by mass, and 40 to 95% by mass. % Is more preferable.
(2) For the same reason, when using a monomer having four radical polymerizable functional groups, the monomer is preferably contained in an amount of 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, 3-5 mass% is still more preferable.
(3) For the same reason, when using a monomer having three radical polymerizable functional groups, it is preferable to contain 0.01 to 30% by mass of this monomer, more preferably 0.1 to 20% by mass, 3-5 mass% is still more preferable.

More specifically, for the same reason, the compound having 5 acryloyloxy groups and one hydrogen group is preferably 30 to 70% by mass, and more preferably 40 to 60% by mass.
Further, a mixture containing 6 to 30% by mass of a compound having 6 acryloyloxy groups, preferably a mixture containing 60 to 40% by mass, 30 to 65% by mass of a compound having 5 acryloyloxy groups and 1 hydrogen group, Preferably 40 to 55% by mass, a compound having 6 acryloyloxy groups 65 to 30% by mass, preferably 55 to 40% by mass, and selected from the compounds (i) to (iv) listed below 1 type, 2 types, 3 types, or 4 types which contain 0.01-5 mass%, Preferably 1-3 mass% is mentioned.
(I) Compound having 1 acryloyloxy group and 5 hydrogen groups (ii) Compound having 2 acryloyloxy groups and 4 hydrogen groups (iii) 3 acryloyloxy groups and 3 hydrogens Compound having group (iv) Compound having four acryloyloxy groups and two hydrogen groups

The compound having 5 methacryloyloxy groups and one hydrogen group is 30 to 70% by mass, preferably 40 to 60% by mass, and the compound having 6 methacryloyloxy groups is 70 to 30% by mass, preferably 60 to 60% by mass. Mixture containing 40% by mass, compound having 5 methacryloyloxy groups and 1 hydrogen group 30-65% by mass, preferably 40-55% by mass, compound having 6 methacryloyloxy groups 65-30 mass %, Preferably 55 to 40% by mass, and one, two, three or four selected from the compounds (i) to (iv) listed below are 0.01 to 5% by mass, Preferably, a mixture containing 1 to 3% by mass can be exemplified.
(I) Compound having 1 methacryloyloxy group and 5 hydrogen groups (ii) Compound having 2 methacryloyloxy groups and 4 hydrogen groups (iii) 3 methacryloyloxy groups and 3 hydrogens Compound having group (iv) Compound having four methacryloyloxy groups and two hydrogen groups

  The trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure forms a fine crosslink in the crosslinkable charge transporting layer, so that the ratio of molecular weight to the number of functional groups in the monomer (molecular weight / functional group number). ) Is preferably 250 or less. When the ratio of the molecular weight to the number of functional groups in the monomer exceeds 250, the cross-linked charge transport layer is soft and wear resistance is somewhat lowered. Therefore, in the monomers exemplified above, modified groups such as EO, PO, caprolactone, etc. It is not preferable to use a monomer having an extremely long modifying group alone in the case of having a monomer. The content of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the crosslinkable charge transport layer is preferably 20 to 80% by mass with respect to the total amount of the crosslinkable charge transport layer. The mass% is more preferable. When the content is less than 20% by mass, the three-dimensional crosslinking density of the crosslinkable charge transport layer is small, and a dramatic improvement in wear resistance may not be achieved as compared with the case of using a conventional thermoplastic binder resin. If it exceeds 80% by mass, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. The electrical characteristics and abrasion resistance required vary depending on the process used, and the thickness of the cross-linked charge transport layer of the photoconductor varies accordingly. A range of mass% is most preferred.

  The radical polymerizable compound having a monofunctional charge transport structure used for the cross-linked charge transport layer is, for example, a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone. , A compound having an electron transport structure such as diphenoquinone, an electron-withdrawing aromatic ring having a cyano group or a nitro group, and having one radical polymerizable functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful. Further, as the charge transporting structure, a triarylamine structure is highly effective, and in particular, when a compound represented by the following structural formula (4) or (5) is used, electrical characteristics such as sensitivity and residual potential are good. To last.

In the structural formula (4) or (5), R ¹ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Good aryl group, cyano group, nitro group, alkoxy group, —COOR ⁷ (where R ⁷ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group or a substituent which may have a substituent) Represents a aryl group which may have a hydrogen atom), a carbonyl halide group or CONR ⁸ R ⁹ (wherein R ⁸ and R ⁹ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, a substituted group) An aralkyl group which may have a group or an aryl group which may have a substituent, which may be the same or different. Ar ¹ and Ar ² represent a substituted or unsubstituted arylene group, and may be the same or different. Ar ³ and Ar ⁴ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3.

In the structural formula (4) or (5), in the substituent of R ¹ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include halogen atoms, nitro groups, cyano groups, alkyl groups such as methyl groups and ethyl groups, alkoxy groups such as methoxy groups and ethoxy groups, aryloxy groups such as phenoxy groups, aryl groups such as phenyl groups and naphthyl groups, It may be substituted with an aralkyl group such as a benzyl group or a phenethyl group.
Of the substituents for R ¹ , particularly preferred are a hydrogen atom and a methyl group.
Substituted or unsubstituted Ar ³ and Ar ⁴ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-fused cyclic hydrocarbon groups, and heterocyclic groups.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

  Examples of the non-condensed cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether, and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, A monovalent group of a non-condensed polycyclic hydrocarbon compound such as diphenylalkyne, triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, polyphenylalkene, or 9,9-diphenylfluorene The monovalent group of a ring assembly hydrocarbon compound is mentioned.

Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.
Moreover, the aryl groups represented by Ar ³ and Ar ⁴ may have substituents as shown in the following (1) to (8), for example.
(1) A halogen atom, a cyano group, a nitro group, etc. are mentioned.
(2) Alkyl groups, preferably C ₁ -C _12, especially C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkyl groups, further including fluorine atoms , a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, which may have a phenyl group substituted by an alkoxy group C 1 -C ₄ alkyl or _C 1 -C ₄ Good. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group, and the like.
(3) An alkoxy group (—OR ₂ ), and R ² represents the alkyl group defined in (2) above. Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group , A trifluoromethoxy group, and the like.
(4) An aryloxy group, and examples of the aryl group include a phenyl group and a naphthyl group. It _may contain an alkoxy group having C 1 -C _4, alkyl group, or a halogen atom C 1 -C ₄ as a substituent. Specific examples include phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 4-methoxyphenoxy group, 4-methylphenoxy group, and the like.
(5) Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group, and the like.
(6) The group represented by following Structural formula (6) is mentioned.

In the structural formula (6), R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group defined in (2), or an aryl group. Examples of the aryl group include a phenyl group, biphenyl group or a naphthyl group, and these may contain an alkoxy group of C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ as a substituent. R ³ and R ⁴ may form a ring together.
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.
(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) Substituted or unsubstituted styryl group, substituted or unsubstituted β-phenylstyryl group, diphenylaminophenyl group, ditolylaminophenyl group, and the like.

The arylene group represented by Ar ¹ and Ar ² is a divalent group derived from the aryl group represented by Ar ³ and Ar ⁴ .

X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.
The substituted or unsubstituted alkylene group is a C ₁ -C ₁₂ , preferably C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkylene group, and these alkylene groups include a fluorine atom, a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, a phenyl group substituted with an alkyl group or a _C 1 -C ₄ alkoxy group C 1 -C ₄ It may be. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.
The substituted or unsubstituted cycloalkylene _group, a cyclic alkylene group of C 5 -C _7, these are the cyclic alkylene group fluorine atom, a hydroxyl _group, an alkyl group of C 1 -C _4, a C 1 -C ₄ It may have an alkoxy group. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the alkylene ether group alkylene group is a hydroxyl group, a methyl group, an ethyl group, etc. You may have the substituent of.
As the vinylene group, a group represented by the following structural formula is preferable.

In Structural Formula, ^{R 5} is hydrogen, an alkyl group (same as the groups defined in (2)), an aryl group (said ^Ar 3, Ar ⁴ same as the aryl group represented by) , A represents 1 or 2, and b represents 1-3.
Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether divalent group include the divalent group of the alkylene ether group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.

  Further, the radically polymerizable compound having the monofunctional charge transport structure is more preferably a compound represented by the following structural formula (7).

However, in the structural formula (7), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, and Rb or Rc is a substituent other than a hydrogen atom and has 1 to 6 carbon atoms. Represents an alkyl group and may be different in the case of plural. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a group represented by the following structural formula.

However, the compound represented by the structural formula is particularly preferably a compound having a methyl group or an ethyl group as a substituent for Rb and Rc.

  The radically polymerizable compound having a monofunctional charge transport structure represented by the structural formulas (4), (5) and (7), particularly the structural formula (7), has a carbon-carbon double bond. Is polymerized by opening to both sides, so that it does not become a terminal structure, but is incorporated in a chain polymer and crosslinked by polymerization with a trifunctional or higher radical polymerizable monomer. Present in the chain and in the cross-linked chain between the main chain and the main chain (this cross-linked chain is intermolecular cross-linked chain between one polymer and the other polymer and folded within one polymer In the main chain, there is an intramolecular cross-linked chain that crosslinks a part of the main chain in the main chain and another part derived from the polymerized monomer at a position away from the main chain). Triarylamines that hang from the chain moiety, whether present or present in the bridge chain The structure has at least three aryl groups arranged in a radial direction from the nitrogen atom and is bulky, but is not directly bonded to the chain part but suspended from the chain part via a carbonyl group or the like. Since these triarylamine structures can be arranged adjacent to each other in the polymer, there is little structural distortion in the molecule. In the case of a surface layer of a photographic photoreceptor, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport path can be adopted.

  Specific examples of the radically polymerizable compound having a monofunctional charge transporting structure of the present invention are shown below, but are not limited to the compounds having these structures.

  The radical polymerizable monomer having the monofunctional charge transporting structure is important for imparting the charge transport performance of the cross-linked charge transport layer. The amount of the radically polymerizable monomer having a monofunctional charge transporting structure is preferably 20 to 80% by mass, more preferably 30 to 70% by mass with respect to the cross-linked charge transporting layer. When the addition amount is less than 20% by mass, the charge transport performance of the crosslinkable charge transport layer cannot be sufficiently maintained, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential may appear due to repeated use. If it exceeds 80% by mass, the content of the trifunctional monomer having no charge transport structure is lowered, and the crosslinking density is lowered, and high wear resistance may not be exhibited. The required electrical characteristics and abrasion resistance differ depending on the process used, and the thickness of the cross-linked charge transport layer of the photoconductor varies accordingly. A range of 70% by weight is most preferred.

The surface layer of the electrostatic latent image carrier of the present invention is preferably a radical polymerizable monomer having no charge transporting structure represented by the structural formula (i) and a monofunctional radical polymerizable compound having a charge transporting structure. In this case, it is 1 to 4 for the purpose of imparting functions such as viscosity adjustment during coating of the surface layer, stress relaxation of the crosslinked surface layer, low surface free energy and reduction of friction coefficient. A functional radical polymerizable monomer and a radical polymerizable oligomer can be used in combination. With this combination, the smoothness of the coating film is improved by reducing the viscosity of the radically polymerizable monomer having no charge transporting structure or the coating solution for the surface layer, and as a result, the crosslinked surface layer is smoothed and the distortion is reduced. This leads to improved cleaning properties and crack suppression in actual use. For this reason, a combination of trifunctional radically polymerizable monomers is preferred.
As these radical polymerizable monomers and oligomers, known ones can be used, and the ratio of these radical polymerizable monomers and oligomers is preferably 1 to 80% by mass, and 5 to 60% by mass with respect to the total amount of the crosslinked surface layer. More preferably, 10-40 mass% is still more preferable. In addition, the viscosity of these radical polymerizable monomers is preferably 1000 mPa · s (25 ° C.) or less, and more preferably 800 mPa · s (25 ° C.) or less.

  The crosslinked charge transporting layer is obtained by curing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure and a radical polymerizable monomer having a monofunctional charge transporting structure. Monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers may be used in combination for the purpose of imparting functions such as viscosity adjustment during construction, stress relaxation of the crosslinkable charge transport layer, lower surface energy and reduced friction coefficient. it can. Known radical polymerizable monomers and oligomers can be used.

Examples of the monofunctional radical monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, and cyclohexyl. Examples include acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer.
Examples of the bifunctional radically polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1 , 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, neopentyl glycol diacrylate, and the like.
Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, and the like. Siloxane repeating units described in JP-60503 and JP-B-6-45770: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethyl Examples include vinyl monomers having a polysiloxane group such as siloxane diethyl, acrylates and methacrylates.
Examples of the radical polymerizable oligomer include an epoxy acrylate oligomer, a urethane acrylate oligomer, a polyester acrylate oligomer, and the like.

The content of the monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers is preferably 50 parts by mass or less and more preferably 30 parts by mass or less with respect to 100 parts by mass of the trifunctional or higher radical polymerizable monomer.
If the content exceeds 50 parts by mass, the three-dimensional crosslink density of the crosslinkable charge transport layer may be substantially reduced, leading to a decrease in wear resistance.

  The cross-linked charge transport layer is obtained by curing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. In order to allow the curing reaction to proceed efficiently, a polymerization initiator may be contained in the coating solution for the crosslinkable charge transport layer. Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. These polymerization initiators may be used alone or in combination of two or more.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5. -Di (peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butyl Peroxycyclohexyl) propane and other peroxide initiators; azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid, etc. And azo initiators.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 4- (2-hydroxyethoxy) phenyl. -(2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-hydroxy-2-methyl-1-phenylpropan-1-one Acetophenone-based or ketal-based photopolymerization of 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, etc. Agents: benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobuty Benzoin ether photopolymerization initiators such as ether and benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, 1 Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene; thioxanthone photopolymerization such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Initiators; Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenol Ruethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrenes, acridine compounds, triazine compounds, imidazole compounds, and the like.
In addition, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.

  The content of the polymerization initiator is preferably 0.5 to 40 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the total content having radical polymerizability.

The crosslinkable charge transport layer coating liquid may contain additives such as various plasticizers, leveling agents, and low molecular charge transport materials that do not have radical reactivity for the purpose of stress relaxation and adhesion improvement, as necessary. .
As the plasticizer, for example, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used.
The amount of the plasticizer used is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the crosslinkable charge transport layer coating solution.
Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain.
The amount of the leveling agent used is preferably 3% by mass or less based on the total solid content of the crosslinkable charge transport layer coating solution.

The crosslinked charge transport layer of the present invention will be described later with a coating liquid containing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by coating and curing on the charge transport layer. In the case where the radically polymerizable monomer is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied.
Examples of the solvent include alcohol solvents such as methanol, ethanol, propanol, and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; tetrahydrofuran, dioxane, Ether solvents such as propyl ether; halogen solvents such as dichloromethane, dichloroethane, trichloroethane, chlorobenzene; aromatic solvents such as benzene, toluene, xylene; cellosolv solvents such as methyl cellosolve, ethyl cellosolve, cellosolve acetate, etc. It is done. These may be used individually by 1 type and may use 2 or more types together.
The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the desired thickness, and is arbitrary. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

In the present invention, after the application of the crosslinkable charge transport layer coating solution, energy is applied from the outside and cured to form a crosslinkable charge transport layer. The external energy used at this time includes heat, light, and the like. , There is radiation. The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays or electromagnetic waves.
The heating temperature is preferably 100 to 170 ° C. When the heating temperature is less than 100 ° C., the reaction rate is slow and the curing reaction may not be completed completely. When the heating temperature exceeds 170 ° C., the temperature becomes too high and the curing reaction proceeds non-uniformly to cause cross-linked charge transport. Large distortions, a large number of unreacted residues, and reaction termination ends may occur in the layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.
As the energy of the light, a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp having an emission wavelength mainly in ultraviolet light can be used, but the visible light source can be adjusted according to the absorption wavelength of the radical polymerizable substance or photopolymerization initiator. Selection is also possible. The irradiation light amount is preferably 50 to 1000 mW / cm ² . When the irradiation light amount is less than 50 mW / cm ² , the curing reaction may take time, and when it exceeds 1000 mW / cm ² , the progress of the reaction becomes non-uniform, and the surface of the crosslinkable charge transport layer is locally May occur, or many unreacted residues and reaction termination ends may occur. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling.
Examples of the energy of the radiation include those using an electron beam.
Among these energies, those using heat and light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

The thickness of the cross-linked charge transport layer is preferably 1 to 10 μm, and more preferably 2 to 8 μm. When the thickness exceeds 10 μm, cracks and film peeling may easily occur. When the thickness is 8 μm or less, the margin is further improved, so that the crosslinking density can be increased, and the material selection for further improving the wear resistance is selected. And curing conditions can be set. On the other hand, the radical polymerization reaction is prone to oxygen inhibition, that is, the surface in contact with the air is not easily cross-linked or non-uniform due to the influence of radical trapping by oxygen. This effect appears remarkably in the surface layer of 1 μm or less, and the cross-linked charge transport layer having a thickness of less than this thickness is likely to have a decrease in wear resistance and uneven wear. In addition, the charge transport layer component in the lower layer is mixed during the application of the crosslinkable charge transport layer. If the coating thickness of the crosslinkable charge transport layer is thin, contaminants spread throughout the layer, resulting in inhibition of the curing reaction and a decrease in the crosslink density.
For these reasons, the cross-linkable charge transport layer of the present invention has a good wear resistance and scratch resistance at a thickness of 1 μm or more. However, if it can be locally scraped to the lower charge transport layer in repeated use, The wear of the portion increases, and the density unevenness of the halftone image tends to occur due to the charging property and sensitivity fluctuation. Therefore, it is desirable that the thickness of the cross-linked charge transport layer be 2 μm or more for longer life and higher image quality.

  Further, as an unexpected effect, when a cross-linked charge transport layer having a thickness of 1 to 10 μm is provided, a pinhole is formed on the surface of the photoreceptor in a durability test related to long-term image formation, particularly in a durability test at high temperature and high humidity. It turned out that it is hard to occur. Although the reason and mechanism are not yet understood, it is considered that the cross-linked charge transport layer of the present invention has high strength, has appropriate elasticity at the same time, and has an appropriate thickness. It is presumed that pinholes generated at the time of image formation on a conventional photoreceptor are related to micro scratches generated on the surface of the photoreceptor due to fine powder such as silica added to the toner, and temperature and humidity. A hard surface layer is advantageous in that it cannot be shaved, but it is thought that if a scratch occurs, it will grow and a pinhole is likely to be formed in a long-term durability test.

In addition to the radically polymerizable compound having a trifunctional or higher functionality that does not have the charge transporting structure and the radically polymerizable compound having a monofunctional charge transportable structure, the crosslinkable charge transporting layer coating liquid includes other components. An additive such as a binder resin having no radically polymerizable functional group, an antioxidant, and a plasticizer can be included.
When these additives are contained in a large amount, the crosslinking density is lowered, the cured product generated by the reaction and the additive are phase-separated and become soluble in the organic solvent. Specifically, it is important to suppress the total content to 20% by mass or less with respect to the total solid content of the coating liquid. Moreover, in order not to make the crosslinking density thin, the total content of monofunctional or bifunctional radically polymerizable monomers, reactive oligomers, and reactive polymers is 20% by mass or less based on the trifunctional radically polymerizable monomers. It is desirable. Further, when a large amount of a radically polymerizable compound having a bifunctional or higher-functional charge transporting structure is contained, a bulky structure is fixed in the crosslinked structure by a plurality of bonds, so that distortion is likely to occur. It is easy to become an aggregate. This can cause solubility in organic solvents. Although different depending on the compound structure, the content of the radical polymerizable compound having a bifunctional or higher functional charge transporting structure is preferably 10% by mass or less based on the radical polymerizable compound having a monofunctional charge transporting structure. Furthermore, in a structure in which a charge generation layer, a charge transport layer, and a crosslinkable charge transport layer are sequentially laminated, it is possible to achieve wear resistance and scratch resistance when the outermost crosslinkable charge transport layer is insoluble in an organic solvent. Is preferable.

  In the present invention, in order to make the crosslinkable charge transport layer insoluble in the organic solvent, (i) the composition of the crosslinkable charge transport layer coating solution, adjustment of the content ratio thereof, and (ii) the crosslinkable charge transport layer coating. Dilution solvent of the working solution, adjustment of solid content concentration, (iii) selection of coating method of crosslinkable charge transport layer, (iv) control of curing condition of crosslinkable charge transport layer, and (v) charge transport layer under layer Although it is important to control such as making it difficult to dissolve, it is not always achieved by one factor.

  As a diluting solvent for the crosslinkable charge transport layer coating solution, when a solvent having a low evaporation rate is used, the remaining solvent may hinder the curing or increase the amount of mixing of lower layer components. Curing and reduced curing density. For this reason, it tends to be soluble in organic solvents. Specifically, tetrahydrofuran, a mixed solvent of tetrahydrofuran and methanol, ethyl acetate, methyl ethyl ketone, ethyl cellosolve and the like are useful, but are selected according to the coating method. Moreover, regarding the solid content concentration, if it is too low for the same reason, it tends to be soluble in an organic solvent. On the contrary, the upper limit concentration may be restricted due to the limitation of thickness and coating solution viscosity, and specifically, it is desirable to use in the range of 10 to 50% by mass.

  As the coating method of the crosslinkable charge transport layer, a method of reducing the solvent content at the time of forming the coating film and the contact time with the solvent is preferable. Specifically, the spray coating method and the amount of the coating liquid are regulated. The ring coating method is particularly preferred. In order to suppress the amount of the lower layer component mixed, it is also effective to use a polymer charge transport material as the charge transport layer and to provide an insoluble intermediate layer for the coating solvent for the cross-linked charge transport layer.

As curing conditions for the pre-crosslinked charge transport layer, if the energy of heating or light irradiation is low, the curing is not completely completed and the solubility in the organic solvent is increased. On the other hand, when cured with very high energy, the curing reaction becomes non-uniform, and it tends to increase the number of uncrosslinked parts and radical stopping parts and to form an aggregate of minute cured products. For this reason, it may become soluble in an organic solvent.
In order to insolubilize the organic solvent, the heat curing conditions are preferably 100 to 170 ° C. and 10 minutes to 3 hours, and the curing conditions by UV light irradiation are 50 to 1000 mW / cm ² , 5 seconds to 5 minutes. In addition, it is desirable to control the temperature rise to 50 ° C. or less to suppress uneven curing reaction.

As a method for making the crosslinkable charge transport layer insoluble in an organic solvent, for example, an acrylate monomer having three acryloyloxy groups and a triarylamine compound having one acryloyloxy group are used as a coating solution. In this case, the use ratio is preferably 7: 3 to 3: 7. Moreover, it is preferable to add 3-20 mass% of the said polymerization initiator with respect to these acrylate compounds whole quantity, and also add a solvent and prepare a coating liquid. For example, in the case where the surface layer is formed by spray coating using a triarylamine donor as the charge transport material and polycarbonate as the binder resin in the charge transport layer which is the lower layer of the cross-linked charge transport layer, As the liquid solvent, tetrahydrofuran, 2-butanone, ethyl acetate and the like are preferable. The use ratio is 3 to 10 times the total amount of the acrylate compound.
Next, for example, the prepared coating solution is applied by spraying or the like on a photoreceptor in which an undercoat layer, a charge generation layer, and the charge transport layer are sequentially laminated on a support such as an aluminum cylinder. Then, it is naturally dried or dried at a relatively low temperature for a short time (25 to 80 ° C., 1 to 10 minutes) and cured by UV irradiation or heating.
For UV irradiation, uses a metal halide lamp, illuminance 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, for example, the case of irradiation with UV light of 200 mW / cm ^2, for example upon curing, the drum of a plurality of lamps What is necessary is just to irradiate the circumferential direction uniformly for about 30 seconds. At this time, the drum temperature is controlled so as not to exceed 50 ° C.
In the case of thermosetting, the heating temperature is preferably from 100 to 170 ° C. For example, when a blowing oven is used as the heating means and the heating temperature is set to 150 ° C., the heating time is from 20 minutes to 3 hours.
After completion of the curing, the electrostatic latent image carrier of the present invention is obtained by further heating at 100 to 150 ° C. for 10 to 30 minutes to reduce the residual solvent.

<Intermediate layer>
In the latent electrostatic image bearing member of the present invention, for the purpose of suppressing charge transport layer component mixing in the cross-linked charge transport layer or improving adhesion between both layers between the charge transport layer and the cross-linked charge transport layer. An intermediate layer can be provided. For this reason, as the intermediate layer, those that are insoluble or hardly soluble in the crosslinking type charge transport layer coating solution are suitable, and generally a binder resin is used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As the method for forming the intermediate layer, the coating method is employed.
The thickness of the intermediate layer is not particularly limited and can be appropriately selected according to the purpose, and is preferably 0.05 to 2 μm.

<Underlayer>
In the electrostatic latent image carrier of the present invention, an undercoat layer can be provided between the conductive support and the photosensitive layer. The undercoat layer generally comprises a resin as a main component. However, considering that the photosensitive layer is applied with a solvent thereon, these resins are resins having a high solvent resistance with respect to general organic solvents. Is desirable. Examples of the resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. In order to prevent moire and reduce residual potential, the undercoat layer is added with a fine powder pigment of a metal oxide such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, or indium oxide. be able to.
For the undercoat layer, a material in which Al ₂ O ₃ is provided by anodic oxidation, an organic material such as polyparaxylylene (parylene), or an inorganic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ is vacuumed. Those provided by the thin film preparation method can also be used favorably. In addition, known ones can be used.
The undercoat layer can be formed using an appropriate solvent and a coating method like the above-described photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention.
There is no restriction | limiting in particular in the thickness of the said undercoat layer, According to the objective, it can select suitably, 0-5 micrometers is preferable.

  In the present invention, for the purpose of improving the environmental resistance, in particular, for the purpose of preventing a decrease in sensitivity and an increase in residual potential, the cross-linked charge transport layer, the charge transport layer, the charge generation layer, the undercoat layer, An antioxidant can be added to each layer such as the intermediate layer.

  Examples of the antioxidant include phenolic compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, and organic phosphorus compounds. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the phenol compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl- 6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3 Tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxy Benzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3 ′) -T-butylphenyl) butyric acid] cricol ester, tocopherols, and the like.

  Examples of the paraphenylenediamines include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine, and the like.

Examples of the hydroquinones include 2,5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl. And hydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone.
Examples of the organic sulfur compounds include dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like. It is done.
Examples of the organic phosphorus compounds include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

In addition, these compounds are known as antioxidants, such as rubber | gum, a plastic, and fats and oils, and a commercial item can be obtained easily.
There is no restriction | limiting in particular in the addition amount of the said antioxidant, According to the objective, it can select suitably, 0.01-10 mass% is preferable with respect to the total mass of the layer to add.

-Synthesis of compounds having a functional charge transport structure-
The compound having a monofunctional charge transport structure in the present invention can be synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (the following structural formula (9)) 113.85 g (0.3 mol) of methoxy group-substituted triarylamine compound (the following structural formula (8)) and 138 g of sodium iodide ( 0.92 mol) was added 240 ml of sulfolane and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 g (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction. About 1.5 L of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). Cyclohexane was added to the obtained pale yellow oil to precipitate crystals. In this way, 88.1 g (yield = 80.4%) of white crystals of the following structural formula (9) was obtained. The melting point is 64.0-66.0 ° C.

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54)
82.9 g (0.227 mol) of the hydroxy group-substituted triarylamine compound (Structural Formula (9)) obtained in the above (1) is dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.2. 4 g, water: 100 ml) was added dropwise. The solution was cooled to 5 ° C., and 25.2 g (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. Thus, Exemplified Compound No. As a result, 80.73 g (yield = 84.8%) of 54 white crystals were obtained. The melting point is 117.5-119.0 ° C.

-Synthesis of compounds having a functional charge transport structure-
The compound dihydroxymethyltriphenylamine having a bifunctional charge transport structure in the present invention can be produced by the following method.
First, 49 g of compound (1) represented by the following reaction formula and 184 g of phosphorus oxychloride were placed in a flask equipped with a thermometer, a condenser, a stirrer, and a dropping funnel, and dissolved by heating. From the dropping funnel, 117 g of dimethylformamide was gradually added dropwise, and then the reaction solution temperature was kept at 85 to 95 ° C. and stirred for about 15 hours. Next, the reaction solution was gradually poured into a large excess of warm water, and then slowly cooled with stirring. Next, the precipitated crystals were filtered and dried, and then purified by adsorption of impurities with silica gel or the like and recrystallization with acetonitrile to obtain Compound (2). Yield was 30 g.
30 g of the obtained compound (2) and 100 ml of ethanol were put into a flask and stirred. After gradually adding 1.9 g of sodium borohydride, the liquid temperature was kept at 40 to 60 ° C. and stirring was performed for about 2 hours. Next, the reaction solution was gradually poured into about 300 ml of water and stirred to precipitate crystals. After filtration, the product was sufficiently washed with water and dried to obtain compound (3). Yield was 30 g.

(Image forming method and image forming apparatus)
The image forming apparatus of the present invention includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, a fixing unit, and a cleaning unit, and further if necessary. And other means appropriately selected, for example, static elimination means, recycling means, control means, and the like.
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, a fixing step, and a cleaning step, and further other steps appropriately selected as necessary, for example, a static elimination step. , Including recycling process, control process, etc.

  The image forming apparatus preferably has a process speed of 200 mm / sec or more, more preferably 240 to 600 mm / sec. When the process speed is less than 200 mm / sec, the effect of the present invention due to temperature does not become more remarkable.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, the fixing step can be performed by the fixing unit, and the other steps can be performed by the other unit.

-Electrostatic latent image forming step and electrostatic latent image forming means-
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier.
The material, shape, structure, size and the like of the latent electrostatic image bearing member are not particularly limited, and can be appropriately selected from known ones. The preferred shape is a drum shape. It is done.
As the electrostatic latent image carrier, the electrostatic latent image carrier of the present invention can be used. Here, the electrostatic latent image carrier has an ambient temperature of 40 ° C. or lower, preferably 15 to 35 ° C., and the ambient temperature around the electrostatic latent image carrier during operation exceeds 40 ° C. The image forming apparatus is preferably used by being mounted at 43 to 65 ° C.
The image forming apparatus charges the surface of the electrostatic latent image carrier by applying a direct current voltage on which the alternating current is superimposed by a charger disposed in contact or non-contact with the surface of the electrostatic latent image carrier. Used for image formation.

  The electrostatic latent image bearing member (electrophotographic photosensitive member) of the present invention can be applied to general electrophotographic apparatuses such as copying machines, laser printers, LED printers, and liquid crystal shutter printers. The present invention can be widely applied to apparatuses such as applied displays, recording, light printing, plate making and facsimile.

The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then performing imagewise exposure, and is performed by the electrostatic latent image forming unit. be able to.
The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise. Prepare.

The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers using corona discharge such as corotrons and corotrons.

The exposure can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure device.
The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger so as to form an image to be formed, and is appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system can be used.
In the present invention, a back light system in which imagewise exposure is performed from the back side of the electrostatic latent image carrier may be employed.
In addition, when the image forming apparatus is used as a copying machine or a printer, image exposure is performed by irradiating a photosensitive member with reflected light or transmitted light from a document, or by reading a document with a sensor and generating a signal according to this signal. This is performed by irradiating the photosensitive member with light by scanning a beam, driving an LED array, or driving a liquid crystal shutter array.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using a toner or a developer, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, toner or developer, and can be appropriately selected from known ones. Preferable examples include at least a developing unit capable of applying toner or developer to the electrostatic latent image in a contact or non-contact manner.

  For the developing device, a dry development system is usually used. Further, it may be a single color developing device or a multicolor developing device, and has, for example, a stirrer for charging the toner or developer by frictional stirring and a rotatable magnet roller. And the like.

  In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state, thereby forming a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically attracted by the electrostatic force. Move to the surface of the latent image carrier. As a result, the electrostatic latent image is developed with toner, and a visible image is formed on the surface of the electrostatic latent image carrier.

  The developer accommodated in the developing device is a developer containing toner, but the developer may be a one-component developer or a two-component developer. As the toner, a commonly used toner can be used.

-Transfer process and transfer means-
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the electrostatic latent image carrier using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer unit (the primary transfer unit and the secondary transfer unit) includes at least a transfer unit that peels and charges the visible image formed on the electrostatic latent image carrier to the recording medium side. Is preferred. There may be one transfer means or two or more transfer means.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

-Fixing process and fixing means-
The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

-Cleaning process and cleaning means-
The cleaning step is a cleaning step of cleaning the electrostatic latent image carrier using a cleaning unit.
Examples of the cleaning means include a cleaning blade, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

  Here, the cleaning means will be described. FIG. 3 is a schematic sectional view of the cleaning mechanism used in the present invention. In the present invention, known cleaning conditions and blade materials can be used. At this time, it is preferable to use the photoconductor in contact with the counter in the rotational direction of the photoconductor.

In FIG. 3, the contact load P is a vector value in the direction normal to the pressing force when the cleaning blade 71 is brought into contact with the photosensitive member 10. Further, the contact angle θ represents an angle formed between a tangent at the contact point of the photoconductor 10 and the blade before deformation. The cleaning blade free length L represents the length of the blade tip point before the deformation from the end of the support member 72.
P is preferably 5 to 50 gf / cm as a preferable value of the contact load P and the contact angle θ of the cleaning blade 71 to the photosensitive member 10. θ is preferably 5 to 35 °. The cleaning blade free length L is preferably 3 to 15 mm. The thickness of the cleaning blade is preferably 0.5 to 10 mm.

  Examples of the material of the rubber blade used in the blade cleaning method include urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, and the like. Among these, urethane rubber is particularly preferable.

By simultaneously controlling the hardness and the rebound resilience of the rubber blade, the reversal of the blade can be effectively suppressed. The JISA hardness at 25 ± 5 ° C. of the rubber blade is preferably 65-80. When the JISA hardness is less than 65, the blade may be easily reversed, and when it exceeds 80, the cleaning performance may be deteriorated. The rebound resilience of the rubber blade is preferably 20 to 75%. If the rebound resilience exceeds 75%, the blade may be easily reversed, and if it is less than 20%, the cleaning performance may deteriorate.
Here, both the JISA hardness and the rebound resilience can be measured based on the vulcanized rubber physical test method of JIS K6301.

The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrostatic latent image carrier. Preferably mentioned.

The recycling step is a step of recycling the electrophotographic color toner removed in the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control means is a process for controlling the respective steps, and can be suitably performed by the control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Here, an aspect of the image forming apparatus of the present invention will be described with reference to FIG.
FIG. 2 is a schematic diagram for explaining the image forming apparatus of the present invention, and a modification example described later also belongs to the category of the present invention.
A photosensitive member 201 as an electrostatic latent image carrier has a photosensitive layer including a charge generation layer, a charge transport layer, and a cross-linked charge transport layer in this order on a support. Although the photoconductor 201 has a drum shape, it may have a sheet shape or an endless belt shape.
As the charger 203, a wire-type charger or a roller-shaped charger is used. A scorotron charger is preferably used for high-speed charging. Although the photosensitive member is charged by this charger, the dot reproducibility becomes better as the electric field strength applied to the photosensitive member is higher.
The image exposure unit 205 uses a light source that can ensure high luminance and can write at high resolution (600 dpi or higher resolution) such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL). .

  A known transfer device can be used as the transfer means, but a combination of the transfer charger 210 and the separation charger 211 is effective as shown in FIG. In addition, a transfer belt and a transfer roller can be used, and it is desirable to use a contact type such as a transfer belt or a transfer roller that generates less ozone. As a voltage / current application method at the time of transfer, either a constant voltage method or a constant current method can be used, but the transfer charge amount can be kept constant, and a constant voltage with excellent stability can be used. The current method is more desirable.

The developing member 206 has one developing sleeve, and the toner developed on the photosensitive member 201 is transferred to the transfer paper 209.
Further, the toner image formed on the photoconductor is transferred onto the transfer paper to become an image on the transfer paper. At this time, there are two methods. One is a method of directly transferring a toner image developed on the surface of the photosensitive member as shown in FIG. 2 to the transfer paper, and the other is once transferring the toner image from the photosensitive member to the intermediate transfer member. It is the method of transferring to. Either case can be used in the present invention.
As such a transfer member, a known member can be used as long as the structure of the present invention can be satisfied.
When positive (negative) charging is performed on the photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (detection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained.

  As a light source such as the static elimination lamp 2, general light emitting materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. . Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Such a light source or the like irradiates the photosensitive member with light by providing a process such as a transfer process, a static elimination process, a cleaning process, or a pre-exposure using light irradiation in addition to the process shown in FIG.
This neutralization mechanism can be omitted when the AC component is superposed and used in the previous charging method, or when the residual potential of the photoreceptor is small. Further, instead of optical static elimination, an electrostatic static elimination mechanism (for example, a static elimination brush applied with a reverse bias or grounded) can be used. In FIG. 2, 208 is a registration roller, and 212 is a separation claw.

  In addition, the toner developed on the photoconductor 201 by the developing unit 206 is transferred to the transfer paper 209. When toner remaining on the photoconductor 201 is generated, the fur brush 214 and the blade 215 remove the toner from the photoconductor. Removed. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

  One mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. An image forming apparatus 100 shown in FIG. 4 includes a photosensitive drum 10 as the electrostatic latent image carrier (hereinafter, also referred to as “photosensitive member 10”), a charging roller 20 as the charging unit, An exposure device 30 as an exposure unit, a development device 40 as the development unit, an intermediate transfer member 50, a cleaning device 60 as the cleaning unit having a cleaning blade, and a static elimination lamp 70 as the static elimination unit. .

  The intermediate transfer member 50 is an endless belt, and is designed to be movable in the direction of an arrow by three rollers 51 that are arranged inside and stretched. Part of the three rollers 51 also functions as a transfer bias roller that can apply a predetermined transfer bias (primary transfer bias) to the intermediate transfer member 50. The intermediate transfer body 50 is provided with a cleaning device 90 having a cleaning blade in the vicinity thereof, and for transferring (secondary transfer) a developed image (toner image) to a transfer sheet 95 as a final transfer material. A transfer roller 80 serving as a transfer unit to which a transfer bias can be applied is disposed to face the transfer roller 80. Around the intermediate transfer member 50, a corona charger 58 for applying a charge to the toner image on the intermediate transfer member 50 is arranged between the photosensitive member 10 and the intermediate transfer member 50 in the rotation direction of the intermediate transfer member 50. It is disposed between the contact portion and the contact portion between the intermediate transfer member 50 and the transfer paper 95.

  The developing device 40 includes a developing belt 41 as the developer carrying member, and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C provided around the developing belt 41. . The black developing unit 45K includes a developer accommodating portion 42K, a developer supplying roller 43K, and a developing roller 44K. The yellow developing unit 45Y includes a developer accommodating portion 42Y, a developer supplying roller 43Y, and a developing roller 44Y. The magenta developing unit 45M includes a developer accommodating portion 42M, a developer supplying roller 43M, and a developing roller 44M, and the cyan developing unit 45C includes a developer accommodating portion 42C and a developer supplying roller 43C. And a developing roller 44C. The developing belt 41 is an endless belt, is rotatably stretched around a plurality of belt rollers, and a part thereof is in contact with the photoconductor 10.

  In the image forming apparatus 100 shown in FIG. 4, for example, the charging roller 20 charges the photosensitive drum 10 uniformly. The exposure device 30 performs imagewise exposure on the photosensitive drum 10 to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 10 is developed by supplying toner from the developing device 40 to form a visible image (toner image). The visible image (toner image) is transferred (primary transfer) onto the intermediate transfer member 50 by the voltage applied from the roller 51, and further transferred (secondary transfer) onto the transfer paper 95. As a result, a transfer image is formed on the transfer paper 95. The residual toner on the photoconductor 10 is removed by the cleaning device 60, and the charge on the photoconductor 10 is temporarily removed by the charge eliminating lamp 70.

  Another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The image forming apparatus 100 shown in FIG. 5 does not include the developing belt 41 in the image forming apparatus 100 shown in FIG. 4, and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and the like around the photoconductor 10. Except that the cyan developing unit 45C is disposed directly opposite, it has the same configuration as that of the image forming apparatus 100 shown in FIG. In FIG. 5, the same components as those in FIG. 4 are denoted by the same reference numerals.

Another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The tandem image forming apparatus shown in FIG. 6 is a tandem type color image forming apparatus. The tandem image forming apparatus includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.
The copying apparatus main body 150 is provided with an endless belt-like intermediate transfer member 50 at the center. The intermediate transfer member 50 is stretched around the support rollers 14, 15 and 16, and can be rotated clockwise in FIG. 6. An intermediate transfer body cleaning device 17 for removing residual toner on the intermediate transfer body 50 is disposed in the vicinity of the support roller 15. The intermediate transfer body 50 stretched by the support roller 14 and the support roller 15 is a tandem type in which four image forming means 18 of yellow, cyan, magenta, and black are arranged in parallel and facing each other along the conveyance direction. A developing device 120 is disposed. An exposure device 21 is disposed in the vicinity of the tandem developing device 120. A secondary transfer device 22 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the tandem developing device 120 is disposed. In the secondary transfer device 22, a secondary transfer belt 24, which is an endless belt, is stretched around a pair of rollers 23, and the transfer paper conveyed on the secondary transfer belt 24 and the intermediate transfer body 50 are in contact with each other. Is possible. A fixing device 25 is disposed in the vicinity of the secondary transfer device 22. The fixing device 25 includes a fixing belt 26 that is an endless belt, and a pressure roller 27 that is pressed against the fixing belt 26.
In the tandem image forming apparatus, a sheet reversing device 28 for reversing the transfer paper for image formation on both sides of the transfer paper is disposed in the vicinity of the secondary transfer device 22 and the fixing device 25. Yes.

  Next, formation of a full color image (color copy) using the tandem image forming apparatus will be described. That is, first, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and the document is set on the contact glass 32 of the scanner 300. 400 is closed.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the contact glass 32. Immediately after that, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, light from the light source is irradiated by the first traveling body 33 and reflected light from the document surface is reflected by the mirror in the second traveling body 34 and is received by the reading sensor 36 through the imaging lens 35 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta and cyan is stored in each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means and cyan image forming means in the tandem image forming apparatus. ) And black, yellow, magenta and cyan toner images are formed in the respective image forming means. That is, each of the image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem image forming apparatus is respectively photosensitive as shown in FIG. On the basis of the body 10 (the black photoreceptor 10K, the yellow photoreceptor 10Y, the magenta photoreceptor 10M, and the cyan photoreceptor 10C), the charger 60 that uniformly charges the photoreceptor, and each color image information. An exposure device that exposes the photoconductor for each color image corresponding image (L in FIG. 7) and forms an electrostatic latent image corresponding to each color image on the photoconductor; A developing device 61 that develops using color toner (black toner, yellow toner, magenta toner, and cyan toner) to form a toner image with each color toner, and the toner image is an intermediate transfer member. The image forming apparatus includes a transfer charger 62 for transferring the image onto 0, a photoconductor cleaning device 63, and a static eliminator 64, and each monochrome image (black image, yellow image, magenta) based on the image information of each color. Image and cyan image) can be formed. The black image, the yellow image, the magenta image, and the cyan image formed in this way are formed on the black photoconductor 10K on the intermediate transfer member 50 that is rotationally moved by the support rollers 14, 15, and 16, respectively. The black image, the yellow image formed on the yellow photoconductor 10Y, the magenta image formed on the magenta photoconductor 10M, and the cyan image formed on the cyan photoconductor 10C are sequentially transferred (primary transfer). Is done. Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member 50 to form a composite color image (color transfer image).

On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed out a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. Each sheet is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 and stopped. Alternatively, the sheet feed roller 142 is rotated to feed out sheets (recording paper) on the manual feed tray 54, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. . The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the sheet.
Then, the registration roller 49 is rotated in synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and a sheet (recording paper) is interposed between the intermediate transfer member 50 and the secondary transfer device 22. The secondary color transfer device 22 transfers the composite color image (color transfer image) onto the sheet (recording paper), thereby transferring the color image onto the sheet (recording paper). Is formed. The residual toner on the intermediate transfer member 50 after image transfer is cleaned by the intermediate transfer member cleaning device 17.

  The sheet (recording paper) on which the color image has been transferred is conveyed by the secondary transfer device 22 and sent to the fixing device 25, where the combined color image (color) is generated by heat and pressure. (Transfer image) is fixed on the sheet (recording paper). Thereafter, the sheet (recording paper) is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the discharge tray 57, or switched by the switching claw 55 and reversed by the sheet reversing device 28 and transferred again. After being guided to the position and recording an image on the back surface, the image is discharged by the discharge roller 56 and stacked on the discharge tray 57.

  In the image forming apparatus and the image forming method of the present invention, the photosensitive layer includes a reaction product of a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. By using an electrostatic latent image carrier having a photosensitive layer with a small amount of wear, high-definition and high-quality images can be formed over a long period of time.

(Process cartridge)
The process cartridge of the present invention develops an electrostatic latent image carrier carrying an electrostatic latent image and the electrostatic latent image carried on the electrostatic latent image carrier using a developer to form a visible image. At least a developing means for forming the film, and other means appropriately selected as necessary.

The latent electrostatic image bearing member has a support and a photosensitive layer including at least a charge generation layer, a charge transport layer, and a crosslinkable charge transport layer in this order on the support, and the crosslinkable charge transport layer includes It includes a reaction product of a trifunctional or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure, and is the same as described above.
The developing means includes at least a developer container that contains toner or developer, and a developer carrier that carries and transports the toner or developer contained in the developer container. Furthermore, a layer thickness regulating member for regulating the thickness of the toner layer to be carried may be provided.
The process cartridge of the present invention can be detachably provided in various image forming apparatuses, and is preferably detachably provided in the above-described image forming apparatus of the present invention.

Here, as the process cartridge, for example, as shown in FIG. 8, a photosensitive member 101 is incorporated, and in addition, a charging unit 102, a developing unit 104, and a cleaning unit 107 are included. Have.
The photoreceptor 101 includes a support and a photosensitive layer including a charge generation layer, a charge transport layer, and a cross-linked charge transport layer in this order on the support.
As the charging unit 102, a known charging member is used as described above.
A light source capable of writing with high resolution is used for the exposure means 103.

  The image forming apparatus of the present invention is configured by integrally combining the above-described electrostatic latent image carrier and components such as a developing device and a cleaning device as a process cartridge, and this unit is detachable from the apparatus main body. You may comprise. Further, at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge, and a single unit that is detachable from the apparatus main body, It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following examples, “part” represents “part by mass”.

(Production Example 1)
-Production of electrostatic latent image carrier 1-
On the aluminum pipe (diameter 30 mm x length 340 mm) that has been cut to prevent moiré, an undercoat layer coating solution having the following composition is applied by an immersion method, and the undercoat layer has a thickness of 2.0 μm. Was provided.

<Coating liquid for undercoat layer>
・ Alkyd resin: 6 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Titanium oxide: 40 parts ・ Methyl ethyl ketone: 50 parts

Next, a charge generation layer coating solution having the following composition was dip coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.
<Coating liquid for charge generation layer>
・ Τ-type metal-free phthalocyanine: 6 parts ・ Polyvinyl butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.): 4 parts ・ 2-butanone: 200 parts ・ Cyclohexanone: 200 parts

Next, a charge transport layer coating solution having the following composition was applied by dip coating and dried to form a charge transport layer having a thickness of 22 μm.
<Coating liquid for charge transport layer>
・ Charge transport material (the following structural formula (A)): 25 parts ・ Bisphenol Z type polycarbonate (weight average molecular weight (Mw) = 150,000): 30 parts ・ Dichloromethane: 300 parts

Next, the resulting charge transport layer was spray-coated with a coating solution for a cross-linked charge transport layer having the following composition, and naturally dried for 20 minutes, and then a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity. : 500 mW / cm ² , Irradiation time: Light irradiation was performed for 60 seconds to cure the coating film. Further, it was dried at 130 ° C. for 20 minutes to provide a cross-linked charge transport layer having a thickness of 5.2 μm. Thus, an electrostatic latent image carrier 1 was produced.
<Coating liquid for crosslinkable charge transport layer>
・ Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure: 10 parts (Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd., molecular weight: 296, functional group number: trifunctional, molecular weight / Number of functional groups = 99)
-Radical polymerizable compound having monofunctional charge transporting structure (Exemplary Compound No. 54) ... 10 parts-1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, Ciba Specialty as photopolymerization initiator) Chemicals) ... 1 part ・ Tetrahydrofuran ... 100 parts

(Production Example 2)
-Production of electrostatic latent image carrier 2-
An electrostatic latent image carrier 2 was produced in the same manner as in Production Example 1 except that the thickness of the crosslinkable charge transport layer was changed to 1.3 μm in Production Example 1.

(Production Example 3)
-Production of electrostatic latent image carrier 3-
An electrostatic latent image carrier 3 was produced in the same manner as in Production Example 1 except that the thickness of the crosslinkable charge transport layer was 7.7 μm in Production Example 1.

(Production Example 4)
-Production of electrostatic latent image carrier 4-
In Production Example 1, the latent charge carrying layer was supported in the same manner as in Production Example 1 except that the coating liquid for the crosslinkable charge transport layer was changed to the following composition and the thickness of the crosslinkable charge transport layer was changed to 5.4 μm. Body 4 was produced.
<Coating liquid for crosslinkable charge transport layer>
・ Trifunctional or higher radical polymerizable monomer having no charge transporting structure: 10 parts (Pentaerythritol tetraacrylate (SR-295, manufactured by Kayaku Sartomer, molecular weight: 352, functional group number: 4 functional, molecular weight / functional Radix = 88)
-Radical polymerizable compound having monofunctional charge transporting structure (Exemplary Compound No. 138) ... 10 parts-1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, Ciba Specialty) as a photopolymerization initiator Chemicals) ... 1 part ・ Tetrahydrofuran ... 100 parts

(Production Example 5)
-Production of electrostatic latent image carrier 5-
An electrostatic latent image carrier 5 was produced in the same manner as in Production Example 4 except that the thickness of the crosslinkable charge transport layer was changed to 1.4 μm in Production Example 4.

(Production Example 6)
-Production of electrostatic latent image carrier 6-
An electrostatic latent image carrier 6 was produced in the same manner as in Production Example 4 except that the thickness of the cross-linked charge transport layer was 7.7 μm in Production Example 4.

(Production Example 7)
-Production of electrostatic latent image carrier 7-
In Production Example 1, the latent charge carrying layer was carried out in the same manner as in Production Example 1 except that the coating liquid for the crosslinkable charge transport layer was changed to the following composition and the thickness of the crosslinkable charge transport layer was 5.0 μm. A body 7 was produced.
<Coating liquid for crosslinkable charge transport layer>
-A trifunctional or higher functional radical polymerizable monomer having no charge transport structure represented by the following structural formula: 10 parts (dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-60, manufactured by Nippon Kayaku Co., Ltd., (Molecular weight: 1263, number of functional groups: 6 functions, molecular weight / number of functional groups = 211)
-Radical polymerizable compound having monofunctional charge transport structure (Exemplary Compound No. 54) ... 10 parts-2,2-dimethoxy-1,2-diphenylethane-1-one as a photopolymerization initiator ( Irgacure 651, manufactured by Ciba Specialty Chemicals) ... 1 part Tetrahydrofuran ... 100 parts

(Production Example 8)
-Production of electrostatic latent image carrier 8-
An electrostatic latent image carrier 8 was produced in the same manner as in Production Example 7 except that the thickness of the cross-linkable charge transport layer was 9.6 μm in Production Example 7.

(Production Example 9)
-Preparation of electrostatic latent image carrier 9-
An electrostatic latent image carrier 9 was produced in the same manner as in Production Example 7 except that the thickness of the cross-linked charge transport layer was 2.0 μm in Production Example 7.

(Production Example 10)
-Production of electrostatic latent image carrier 10-
An electrostatic latent image carrier 10 was produced in the same manner as in Production Example 7 except that the thickness of the crosslinkable charge transport layer was 3.2 μm in Production Example 7.

(Production Example 11)
-Production of electrostatic latent image carrier 11-
In Production Example 1, the electrostatic latent image was changed in the same manner as in Production Example 1 except that the coating liquid for the crosslinkable charge transport layer was changed to the following composition and the thickness of the crosslinkable charge transport layer was 5.0 μm. A carrier 11 was produced.
<Coating liquid for crosslinkable charge transport layer>
-Radical polymerizable monomer having no charge transporting structure represented by the following structural formula: 95 parts Dipentaerythritol hexaacrylate (Mix ratio of hexaacrylate and pentaacrylate, 1: 1 mixture, KAYARAD DPHA, Nippon Kayaku (Made by company)
(Mix ratio 1: 1 mixture of a = 5, b = 1 and a = 6, b = 0 compound)
-Radical polymerizable compound having a monofunctional charge transporting structure ... 95 parts (Exemplary Compound No. 54)
Photopolymerization initiator: 10 parts 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
・ Tetrahydrofuran ... 1200 parts

(Production Example 12)
-Production of electrostatic latent image carrier 12-
In Production Example 11, the radical polymerizable monomer having no charge transporting structure contained in the coating solution for the crosslinkable charge transport layer was changed to the following, and the film thickness of the crosslinkable charge transport layer was 5.0 μm. An electrostatic latent image carrier 12 was produced in the same manner as in Production Example 11 except that
<Coating liquid for crosslinkable charge transport layer>
-Radical polymerizable monomer that does not have a charge transporting structure (2 types of mixed monomers using the following (1) and (2) at a mass ratio of 1: 1): 95 parts (1) Represented by the following structural formula Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd.)
(2) Trimethylolpropane triacrylate (TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following structural formula

(Production Example 13)
-Production of electrostatic latent image carrier 13-
In Production Example 11, the radical polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transport layer was changed to the following, and the film thickness of the crosslinkable charge transport layer was changed to 5.0 μm. An electrostatic latent image carrier 13 was produced in the same manner as in Production Example 11 except that
<Coating liquid for crosslinkable charge transport layer>
-Radical polymerizable monomer that does not have a charge transporting structure (two types of mixed monomers using the following (1) and (2) at a mass ratio of 1: 1): 95 parts (1) represented by the following structural formula Dipentaerythritol hexaacrylate (Mix ratio of hexaacrylate and pentaacrylate 1: 1 mixture; KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.)
(A mixture of a = 5, b = 1 and a = 6, b = 0 compound in a mass ratio of 1: 1)
(2) Trimethylolpropane triacrylate (TMPTA, manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following structural formula

(Production Example 14)
-Production of electrostatic latent image carrier 14-
An electrostatic latent image carrier 14 was produced in the same manner as in Production Example 13 except that the film thickness of the crosslinkable charge transport layer was changed to 9.5 μm in Production Example 13.

(Production Example 15)
-Production of electrostatic latent image carrier 15-
An electrostatic latent image carrier 15 was produced in the same manner as in Production Example 13 except that the thickness of the cross-linked charge transport layer was 2.3 μm in Production Example 13.

(Comparative Production Example 1)
-Production of electrostatic latent image carrier 16-
An electrostatic latent image carrier 16 was produced in the same manner as in Production Example 1 except that the crosslinkable charge transport layer was not provided and the thickness of the charge transport layer was 27 μm in Production Example 1.

(Comparative Production Example 2)
-Production of electrostatic latent image carrier 17-
In the same manner as in Production Example 1, up to the charge transport layer was produced. On this charge transport layer, an adhesive layer coating solution having the following composition was applied and subjected to a heat treatment at 100 ° C. for 30 minutes to form an adhesive layer having a thickness of 0.3 μm.
<Coating liquid for adhesive layer>
-Silyl acrylate (PC-7A, manufactured by Shin-Etsu Chemical Co., Ltd.) ... 6 parts-2-butanone ... 200 parts

Next, molecular sieve 4A was added to a methanol solution of polysiloxane composed of 80 mol% of methylsiloxane units and 20 mol% of methyl-phenylsiloxane units, and allowed to stand for 15 hours for dehydration treatment. 10 parts of this solution was dissolved in 10 parts of toluene, and 1 part of methyltrimethoxysilane and 0.2 part of dibutyltin acetate were added thereto to prepare a uniform coating solution for a protective layer.
The obtained protective layer coating solution was applied onto the adhesive layer, and heat-cured at 120 ° C. for 1 hour to form a protective layer having a dry thickness of 3 μm. Thus, an electrostatic latent image carrier 17 was produced.

(Comparative Production Example 3)
-Production of electrostatic latent image carrier 18-
In Production Example 1, the crosslinkable charge transport layer was not provided, and the binder resin of the charge transport layer was changed from a bisphenol Z type polycarbonate resin to a polyarylate resin of the following structural formula (B) (weight average molecular weight (Mw) = 80000, Mw / The electrostatic latent image carrier 18 was produced in the same manner as in Production Example 1 except that the thickness was changed to Mn = 2.8) and the thickness was changed to 27 μm.
However, n represents the number of polymerization.

(Comparative Production Example 4)
-Production of electrostatic latent image carrier 19-
In Comparative Production Example 3, a polyarylate resin (weight average molecular weight (Mw) = 80000, Mw / Mn = 2.8) was changed to a polyarylate resin (weight average molecular weight (Mw) = 200000, Mw / Mn = 2.8). An electrostatic latent image carrier 19 was produced in the same manner as in Comparative Production Example 3 except that the change was made.

( Reference Examples 1 to 10, Examples 11 to 15 and Comparative Examples 1 to 4)
The obtained electrostatic latent image carriers 1 to 19 were evaluated as follows using an image forming apparatus (Imagio Neo 270, manufactured by Ricoh Co., Ltd.) and a modified exhaust fan. The results are shown in Table 3.

The room for the evaluation was 23 ° C. and 50% RH, and thermocouples were mounted at the development position and the cleaning position in order to measure the ambient temperature around the electrostatic latent image carrier.
First, a similar electrostatic latent image carrier prepared separately is attached to the apparatus, and the ambient temperature in the apparatus becomes 42 ± 2 ° C. while the apparatus is operated by controlling the operation / stop of the exhaust fan. I made it.
Subsequently, the initial potential was measured after replacing the electrostatic latent image carrier for evaluation. The dark portion potential Vd = −750V and the light portion potential Vl = −200V. Furthermore, 60,000 images (intermittent mode that stops once after every 5 copies) of 5% printing images were made on A4 size plain paper. Thereafter, the wear amount of the thickness of the electrostatic latent image carrier was measured with an eddy current thickness gauge (Fischer Scope).
Furthermore, by controlling the operation and stoppage of the exhaust fan so that the ambient temperature in the device is 35 ± 2 ° C and 52 ± 2 ° C, respectively, while the device is in operation, the same evaluation is performed and the amount of wear is determined. Was measured.

( Reference Examples 16 to 18, Examples 19 to 20 and Comparative Examples 5 to 7)
Using an image forming device (Imagio Neo 270, manufactured by Ricoh Co., Ltd.), remodeling the line speed to 150, 200, 240, 270 mm / sec and using a remodeled exhaust fan as follows: And evaluated. The results are shown in Table 4.

  The room for the evaluation was 23 ° C. and 50% RH, and thermocouples were mounted at the development position and the cleaning position in order to measure the ambient temperature around the electrostatic latent image carrier. First, a similar electrostatic latent image carrier prepared separately is attached to the apparatus, and the ambient temperature in the apparatus becomes 42 ± 2 ° C. while the apparatus is operated by controlling the operation / stop of the exhaust fan. I made it. Next, the electrostatic latent image bearing member for evaluation was replaced with an initial potential, and the charging condition and the exposure condition were adjusted so that the dark part potential Vd = −750V and the bright part potential Vl = −200V. Further, 60,000 copies of an image with a printing ratio of 5% were made on A4 size plain paper. Thereafter, the amount of wear of the electrostatic latent image carrier thickness was measured with an eddy current thickness gauge (Fischerscope).

( Reference Examples 21-30, Examples 31-35 and Comparative Examples 8-11)
Using an image forming apparatus (Imagio Neo 270, manufactured by Ricoh Co., Ltd.), the charging method from the contacted charging means is modified to a method in which an AC voltage is superimposed on a DC voltage (charging condition: DC voltage: -700 V, AC voltage) The peak-to-peak voltage of 1.6 kV, frequency: 1.4 kHz) was evaluated using a modified exhaust fan as follows. The results are shown in Table 5.

The room for the evaluation was 23 ° C. and 50% RH, and thermocouples were mounted at the development position and the cleaning position in order to measure the ambient temperature around the electrostatic latent image carrier. First, a similar electrostatic latent image carrier prepared separately is attached to the apparatus, and the operation and stop of the exhaust fan are controlled so that the atmospheric temperature in the apparatus becomes 42 ± 2 ° C. while the apparatus is in operation. I made it. Next, the electrostatic latent image bearing member for evaluation was replaced with an initial potential, and the charging condition and the exposure condition were adjusted so that the dark part potential Vd = −750V and the bright part potential Vl = −200V. Furthermore, 30,000 sheets of images with a printing ratio of 5% were copied on an A4 size plain paper (intermittent mode that stops once after every five copies). Thereafter, the amount of wear of the electrostatic latent image carrier thickness was measured with an eddy current thickness gauge (Fischerscope).
Furthermore, by controlling the operation and stoppage of the exhaust fan so that the ambient temperature in the device is 35 ± 2 ° C and 52 ± 2 ° C, respectively, while the device is in operation, the same evaluation is performed and the amount of wear is determined. Was measured.

From the results of Tables 3 to 5, by using the electrostatic latent image carriers of the present invention of Production Examples 11 to 15, even when used under specific conditions such as a high-temperature atmosphere, the wear amount does not increase and is extremely high. It can be seen that it exhibits durable characteristics.
In contrast, the electrostatic latent image carriers of Comparative Production Examples 1 to 4 have a large amount of wear and low durability, and even if the amount of wear is small, the temperature dependency of the amount of wear is high, and durability and stability are high. It is recognized that it is extremely inferior.

The electrostatic latent image carrier of the present invention can provide an electrostatic latent image carrier that has good wear resistance and does not reduce wear resistance even in an actual image forming apparatus. In addition, the electrostatic latent image carrier of the present invention exhibits good wear resistance even in a system having a process speed exceeding 200 mm / sec, and is disposed in contact or non-contact with the surface of the electrostatic latent image carrier. In the process of charging the electrostatic latent image carrier by applying a DC voltage superimposed with alternating current from the charger, the blade cleaning method showed good wear resistance, and extremely excellent in durability and practicality An electrostatic latent image carrier can be provided.
An image forming method, an image forming apparatus, and a process cartridge using an electrostatic latent image carrier of the present invention are a full color copying machine, a full color laser printer, and a full color plain paper using a direct or indirect electrophotographic multicolor image developing system. Widely used for fax machines.

FIG. 1 is a schematic sectional view showing an example of the layer structure of the electrostatic latent image carrier of the present invention. FIG. 2 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 3 is a schematic explanatory view showing an example of the cleaning means used in the present invention. FIG. 4 is a schematic explanatory view showing an example in which the image forming method of the present invention is carried out by the image forming apparatus of the present invention. FIG. 5 is a schematic explanatory view showing another example in which the image forming method of the present invention is implemented by the image forming apparatus of the present invention. FIG. 6 is a schematic explanatory view showing an example in which the image forming method of the present invention is implemented by the image forming apparatus (tandem color image forming apparatus) of the present invention. FIG. 7 is a partially enlarged schematic explanatory view of the image forming apparatus shown in FIG. FIG. 8 is a schematic explanatory view showing an example of the process cartridge of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support body 2 Charge generation layer 3 Charge transport layer 4 Crosslinkable charge transport layer 10 Photoreceptor (photoreceptor drum)
10K black photoconductor 10Y yellow photoconductor 10M magenta photoconductor 10C cyan photoconductor 14 support roller 15 support roller 16 support roller 17 intermediate transfer cleaning device 18 image forming means 20 charging roller 21 exposure device 22 secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure belt 28 Sheet reversing device 30 Exposure device 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Developer roller 44Y Developer roller 44M Developer Roller 44C Development roller 45K Black development unit 45Y Yellow development unit 45M Magenta development unit 45C Cyan development unit 49 Registration roller 50 Intermediate transfer member 51 Roller 52 Separation roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 discharge tray 58 corona charger 60 cleaning device 61 developing device 62 transfer charger 63 photoconductor cleaning device 64 discharger 70 discharger lamp 71 cleaning blade 72 support member 80 transfer roller 90 cleaning device 95 transfer paper 100 image forming device 101 electrostatic Latent image carrier (photoconductor)
DESCRIPTION OF SYMBOLS 102 Charging means 103 Exposure 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means 120 Tandem type developer 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separating roller 146 Paper feed path 147 Transport roller 148 Paper feed path 150 Image forming apparatus body 200 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)

Claims (6)

An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, a developing step of developing the electrostatic latent image with toner to form a visible image, and the visible image A transfer process for transferring the image onto a recording medium, a fixing process for fixing the transferred image transferred onto the recording medium, and a cleaning process for cleaning the electrostatic latent image carrier,
The electrostatic latent image carrier has a support and a photosensitive layer formed by laminating at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer in this order on the support, An electrostatic latent image carrier in which a crosslinkable charge transport layer contains a reaction product of a tri- or higher functional radical polymerizable compound having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. And
The electrostatic latent image carrier is used by being mounted on an image forming apparatus having an ambient temperature of 40 ° C. or lower and an ambient temperature around the electrostatic latent image carrier in operation exceeding 40 ° C .;
The image forming method according to claim Rukoto used the charge-transporting trifunctional or more radical polymerizable compound having no structure of two or more. The image forming method according to claim 1, wherein the image forming method is used in an image forming apparatus having a process speed of 200 mm / sec or more. The image forming method according to claim 1, wherein the cross-linked charge transport layer has a thickness of 1 to 10 μm. The image forming method according to claim 1, wherein the thickness of the cross-linked charge transport layer is 2 to 8 μm. 5. The image formation according to claim 1, wherein the radical polymerizable functional group in the trifunctional or higher functional radical polymerizable compound and the monofunctional radical polymerizable compound is at least one of an acryloyloxy group and a methacryloyloxy group. Way . 2. The image forming apparatus according to claim 1, wherein the electrostatic latent image bearing member surface is charged with a DC voltage superposed on a surface of the electrostatic latent image bearing member by applying a DC voltage superimposed on a surface of the electrostatic latent image bearing member. 6. The image forming method according to any one of 5 above .