JP2014142571A - Electrophotographic photoreceptor and manufacturing method of the same, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of maintaining extremely stable electric characteristics and high mechanical durability for a long period, so as to provide images with high definition and high quality for a long period.SOLUTION: An electrophotographic photoreceptor comprises: a support; and a photosensitive layer and a surface layer on the support, and the surface layer contains an organic-inorganic hybrid material, and clay minerals. An aspect in which the organic-inorganic hybrid material is an epoxy resin-silica hybrid material, an aspect in which the organic-inorganic hybrid material is an epoxy resin-tetrafunctional silica hybrid material, and the like are preferable.

Description

  The present invention relates to an electrophotographic photosensitive member used for a copying machine, a laser printer, a facsimile, and the like, a method for manufacturing the electrophotographic photosensitive member, and an image forming apparatus using the electrophotographic photosensitive member.

In recent years, organic photoreceptors (OPCs) have been widely used in copying machines, facsimile machines, laser printers, or their combined machines in place of inorganic photoreceptors because of their good performance and various advantages. Reasons for this include, for example, (i) optical characteristics such as the light absorption wavelength range and the amount of absorption, (ii) electrical characteristics such as high sensitivity and highly stable charging characteristics, and (iii) Examples include a wide selection range, (iv) ease of production, (v) low cost, and (vi) non-toxicity.
On the other hand, recently, the diameter of the photosensitive member has been reduced due to the downsizing of the image forming apparatus, and the high durability of the organic photosensitive member has been eagerly desired due to the increase in the speed of the machine and the maintenance-free movement. From this point of view, the organophotoreceptor is generally soft because the surface layer contains a low molecular charge transport material and an inert polymer, and when used repeatedly in an electrophotographic process, it depends on the development system and cleaning system. There is a drawback that wear is likely to occur due to a mechanical load.

  In addition, due to the demand for higher image quality, the rubber hardness of the cleaning blade and the contact pressure must be increased for the purpose of improving the cleaning property as the particle size of the toner particles is reduced. It is a factor that promotes wear. Such wear of the photoreceptor deteriorates electrical characteristics such as sensitivity deterioration and chargeability, and causes abnormal images such as image density reduction and background stains. In addition, scratches in which wear locally occurs result in streak-like stain images due to poor cleaning. At present, the life of the photoreceptor has been replaced by the rate of wear and scratches.

  In addition, image quality is deteriorated due to a decrease in charging potential, an increase in residual potential, a change in sensitivity, and the like due to repeated use. The cause of this deterioration is not completely understood, but as one of the factors, ozone, NOx and other oxidizing gases released from the corona discharge charger, and atmospheric ozone and NOx and other oxidizing properties Gases have been found to cause significant damage to the organic photosensitive layer.

  Examples of techniques for improving the abrasion resistance of the organic photosensitive layer include, for example, (1) using a curable binder for the surface layer (see Patent Document 1), and (2) using a polymer charge transport material. (Refer to Patent Document 2), (3) a surface layer in which an inorganic filler is dispersed (refer to Patent Document 3), and the like. Among these, 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, resulting in a decrease in image density. It tends to occur. Further, those using the polymer type charge transport material (2) and those obtained by dispersing the inorganic filler (3) are required for organic photoreceptors, although they can improve wear resistance to some extent. The durability has not been fully satisfied. Furthermore, in the case where the inorganic filler (3) is dispersed, the residual potential increases due to charge traps existing on the surface of the inorganic filler, and the image density tends to decrease. In the techniques (1), (2), and (3), the total durability including the electrical durability and mechanical durability required for the organic photoreceptor is sufficient. Not satisfied with the minute.

  Further, an organic photoreceptor having a cross-linked charge transport layer obtained by curing the trifunctional or higher functional radical polymerizable monomer having no charge transport structure (1) and a monofunctional radical polymerizable compound having a charge transport structure. Have been proposed (see, for example, Patent Documents 4 to 6). In these proposals, cracking of the photosensitive layer is suppressed simultaneously with mechanical and electrical durability by using a monofunctional radically polymerizable compound having a charge transporting structure. However, depending on the method of forming the crosslinkable charge transport layer, the film density of the crosslinkable charge transport layer may not be sufficiently high. In such a case, a dense crosslink surface layer is not formed, and an oxidizing gas or The characteristics may not be stable due to environmental changes such as humidity, and an afterimage may occur as an abnormal image in an actual use environment.

  In order to achieve both improved wear resistance and suppression of abnormal images such as afterimages, a polyfunctional curable acrylate monomer was used for the cross-linked surface layer, and a mixed pigment of disazo pigment and phthalocyanine pigment was used as the charge generation material. An electrophotographic photosensitive member has been proposed (see Patent Document 7). In this proposal, the occurrence of abnormal images such as afterimages is suppressed over a long period of time by reducing charge traps inside the electrophotographic photosensitive member against changes in the characteristics of the crosslinked surface layer. Degradation of the material constituting the crosslinked surface layer due to unavoidable is inevitable, and it has not been possible to maintain sufficiently stable image formation.

  In addition, an electrophotographic photoreceptor containing a cured product of a hole transporting compound having two or more chain polymerizable functional groups in the same molecule in the surface layer has been proposed (see Patent Document 8). However, in this proposed electrophotographic photosensitive material, since the bulky hole transporting compound has two or more chain polymerizable functional groups, distortion occurs in the cured product, resulting in high internal stress, There are cases where cracks are likely to occur over time, and it does not have sufficient durability. Moreover, since the distortion of the cured product is large, the film density may not be sufficiently improved, and a sufficiently high wear resistance cannot be achieved. Furthermore, since the film density is low, a dense cross-linked film is not realized, and the characteristics may not be stable due to environmental changes such as oxidizing gas and humidity, and an afterimage may occur as an abnormal image in an actual use environment. Thus, stable image output has not been realized over a long period of time.

  Further, for the purpose of reducing the influence of oxidizing gas, it has been proposed to add at least two kinds of antioxidants to the crosslinked surface layer coating solution (see Patent Documents 9 and 10). In these proposals, formation of high-quality images over a longer period of time has been achieved. However, when photocuring the cross-linked surface layer, high energy light is also irradiated to the compounds having charge transporting structures and antioxidants. As a result, it is difficult to maintain the sufficiently stable electrical characteristics and electrophotographic photosensitive member characteristics, and high-quality image output could not be maintained over a long period of time. .

  In addition, an image forming apparatus aimed at suppressing the occurrence of abnormal images due to oxidizing gas has been proposed (see Patent Documents 11 and 12). However, in these proposed image forming apparatuses, it is necessary to provide a heater for controlling the temperature of the electrophotographic photosensitive member and a discharge product removing member, all of which increase the size of the apparatus, increase the power consumption, and increase the cost. There are challenges.

  Therefore, it is difficult to achieve both high mechanical durability and stable electrical characteristics over a long period of time, and the present situation is that high-quality image output over a long period of time has not yet been realized.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention provides an electrophotographic photosensitive member that can maintain extremely stable electrical characteristics and high mechanical durability over a long period of time and can obtain a high-definition high-quality image over a long period of time. The purpose is to provide.

The electrophotographic photosensitive member of the present invention as a means for solving the problems comprises a support, and a photosensitive layer and a surface layer on the support.
The surface layer contains an organic-inorganic hybrid material and a clay mineral.

  According to the present invention, the conventional problems can be solved, the object can be achieved, extremely stable electric characteristics and high mechanical durability can be maintained over a long period of time. In addition, an electrophotographic photosensitive member capable of obtaining a high-definition high-quality image can be provided.

FIG. 1 is a view showing an example of the layer structure of the electrophotographic photosensitive member of the present invention. FIG. 2 is a view showing another example of the layer structure of the electrophotographic photosensitive member of the present invention. FIG. 3 is a view showing another example of the layer structure of the electrophotographic photosensitive member of the present invention. FIG. 4 is a diagram showing an example of a process cartridge used in the present invention. FIG. 5 is a schematic view showing an example of an image forming apparatus used in the present invention. FIG. 6 is a schematic diagram illustrating an example of a state where a gap forming member is provided on the charging roller. FIG. 7 is a schematic view showing another example of the image forming apparatus of the present invention. FIG. 8 is a schematic view showing still another example of the image forming apparatus of the present invention. FIG. 9 is a diagram illustrating an A4 size chart in which a character part and a halftone part used for actual machine evaluation of the example are mixed.

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor of the present invention comprises a support, a photosensitive layer and a surface layer on the support, and further comprises other layers as necessary.

  In the present invention, there is provided an electrophotographic photosensitive member capable of achieving both extremely stable electrical characteristics and high mechanical durability over a long period of time by including the organic-inorganic hybrid material and the clay mineral in the surface layer. can get. That is, the surface layer contains a plate-like clay mineral having a large aspect ratio (long side / short side), thereby allowing transmission of factors that change the electrical characteristics of the electrophotographic photosensitive member such as oxidizing gas and water vapor. Thus, an electrophotographic photosensitive member having higher reliability can be realized. On the other hand, when the surface layer contains an organic-inorganic hybrid material having high hardness and high elasticity, it is possible to improve the mechanical durability of the electrophotographic photosensitive member. Excellent electrical durability and mechanical durability can be maintained.

  The functional group number of the silane species in the organic-inorganic hybrid material is preferably 4 or more from the viewpoint of mechanical durability. That is, by polymerizing a tetrafunctional or higher functional silane compound, a high hardness surface layer having a very high crosslink density can be obtained, and it is uniform and smooth, and high wear resistance and scratch resistance can be achieved. Although it is important to increase the crosslink density in this way, if a large number of bonds are formed instantaneously in the polymerization reaction, internal stress due to volume shrinkage occurs. Since the internal stress increases as the thickness of the surface layer increases, cracks and film peeling tend to occur when the entire surface layer is cured. Even if this phenomenon does not appear in the beginning, it is used repeatedly in the electrophotographic process, and it occurs over time due to the effects of hazards and thermal fluctuations in the charging process, development process, transfer process, and cleaning process. There is a problem that it becomes easy.

Examples of methods for solving the above 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) flexibility. Examples thereof include a method of softening the surface layer such as using a polyfunctional monomer having a group. However, in any of these methods, the crosslinking density of the surface layer becomes dilute, and a dramatic improvement in wear resistance cannot be achieved.
In the electrophotographic photoreceptor of the present invention, by forming the surface layer containing the organic-inorganic hybrid material and the clay mineral so that the average thickness is 0.5 μm to 5 μm, there is no occurrence of cracks and film peeling, Very high wear resistance can be achieved. Furthermore, by making the average thickness of the surface layer as thin as 0.5 μm to 3 μm, the margin for the above problem is improved, which leads to improvement of electrical characteristics required for the electrophotographic photosensitive member.
As described above, in the electrophotographic photosensitive member of the present invention, the reason why the occurrence of cracks and film peeling can be suppressed is that the surface layer can be thinned so that the internal stress does not increase, and the photosensitive layer or charge is formed below the surface layer. Since it has a transport layer, the internal stress of the surface layer can be relaxed.
Therefore, the electrophotographic photoreceptor of the present invention does not need to contain a non-polymerizable polymer material in the surface layer because the surface layer contains the organic-inorganic hybrid material and the clay mineral, and is generated at that time. Scratches and toner filming caused by incompatibility caused by the reaction between a non-polymeric polymer material and a polymerizable compound are less likely to occur, and extremely stable electrical characteristics and high mechanical durability over a long period of time And a high-definition high-quality image can be obtained over a long period of time.

<Surface layer>
The surface layer contains an organic-inorganic hybrid material and a clay mineral, and contains a curing agent and, if necessary, other components.

<< Organic-inorganic hybrid material >>
The organic-inorganic hybrid material is a hybrid material in which an organic polymer in which inorganic components are uniformly dispersed is used as a matrix. By adding the organic-inorganic hybrid material, it is possible to improve mechanical properties and heat resistance while maintaining the lightness and durability that are the characteristics of the organic polymer.
There is no restriction | limiting in particular as said organic polymer, According to the objective, it can select suitably, For example, a polyamide resin, a polystyrene resin, an acrylic resin, an epoxy resin, a polyimide resin, a polycarbonate resin, a polyurethane resin etc. are mentioned.
There is no restriction | limiting in particular as said inorganic component, According to the objective, it can select suitably, For example, a metal oxide, a metal microparticle, etc. are mentioned. Among these, metal oxides are particularly preferable.
Examples of the metal oxide include silica, alumina, titania, zirconia, and the like.
Examples of the metal fine particles include iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, and gold.

The organic-inorganic hybrid material is not particularly limited and may be appropriately selected depending on the intended purpose. However, an organic material obtained by dispersing silica as an inorganic component in an organic polymer obtained by a sol-gel method is combined. An inorganic hybrid material is preferable, and a regioselective molecular hybrid material in which silica is allowed to act on a specific position of the organic polymer is more preferable because a stable organic-inorganic hybrid material can be realized.
As a regioselective molecular hybrid material that causes the silica to act on a specific position of the organic polymer, it can be sol-gelled at a relatively low temperature, and from the point of achieving both physical properties and electrophotographic photoreceptor characteristics, The epoxy resin-silica hybrid material represented by the general formula (A) is preferable.

[General formula (A)]
However, in said general formula (A), R ^<101> and R ^<102> may be the same or different, and represents either a hydrogen atom or an alkyl group, and R ^{< 103>} and R ^<104> are a hydrogen atom, an alkyl, Represents any one of a group and an alkoxy group, and R ¹⁰⁵ represents either a hydrogen atom or an alkyl group. m and n represent the number of repetitions and are integers of 1 or more.

In the said general formula (A), as an alkyl group of R < ¹⁰¹ > -R < ¹⁰⁵ >, a C1-C10 thing is preferable, for example, a methyl group, an ethyl group, a propyl group, etc. are mentioned.
In the general formula (A), the alkoxy group represented by R ¹⁰³ and R ¹⁰⁴ is preferably an alkoxy group having 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a propoxy group.
Among these, in the general formula (A), R ¹⁰¹ , R ¹⁰² , and R ¹⁰⁵ are methyl groups, and R ¹⁰³ and R ¹⁰⁴ are methoxy groups. In the general formula (A), , R ¹⁰¹ , R ¹⁰² , and R ¹⁰⁵ are methyl groups, R ¹⁰³ is a methyl group, and R ¹⁰⁴ is a methoxy group, an epoxy resin-trifunctional silica hybrid is preferable. Hybrids are particularly preferred.

  As the epoxy resin-silica hybrid material as the organic-inorganic hybrid material, an appropriately synthesized material or a commercially available product may be used. Examples of the commercially available products include Composeran E102 (epoxy resin-4 functional silica hybrid), Composelan E102B (epoxy resin-4 functional silica hybrid), Composelan E103A (epoxy resin-3 functional silica hybrid), Composelan E103D (epoxy resin- (Trifunctional Silica Hybrid), Composelan E201 (Epoxy Resin-3 Functional Silica Hybrid), Composelan E202C (Epoxy Resin-4 Functional Silica Hybrid) (all manufactured by Arakawa Chemical Industries, Ltd.), and the like.

  There is no restriction | limiting in particular in content in the said surface layer of the said organic-inorganic hybrid material, Although it can select suitably according to the objective, 10 mass%-90 mass% are preferable, and 30 mass%-70 mass% are More preferred. If the content is less than 10% by mass, sufficient mechanical durability may not be achieved, and stable image formation may not be achieved over a long period of time. If the content exceeds 90% by mass, the curing agent is insufficient. In some cases, it is impossible to achieve stable image formation over a long period of time due to poor curing caused by the above.

<< Curing agent >>
The organic-inorganic hybrid material is preferably cured using a curing agent in order to achieve curing under mild conditions.
As the curing agent, when the epoxy resin-silica hybrid material is used, amines, polyamide resins, imidazoles, polymercaptan curing agents, acid anhydrides generally known as curing agents for epoxy resins are used. And latent curing agents, light / ultraviolet curing agents, and the like. Among these, acid anhydrides are preferable from the viewpoint that stable electrophotographic photoreceptor characteristics can be realized by being incorporated into the crosslinked structural unit in the epoxy resin.
The acid anhydride is not particularly limited and may be appropriately selected depending on the intended purpose.For example, phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, Examples include 4-methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride, methyl hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and the like. These may be used individually by 1 type and may use 2 or more types together.
The content of the curing agent in the surface layer is not particularly limited and can be appropriately selected according to the purpose, but is stable by blending so as to have a hydrogen activity equivalent to the epoxy equivalent of the epoxy resin. Organic-inorganic hybrid can be realized.

<< Clay mineral >>
The clay mineral is a plate-like particle having a large aspect ratio. When the clay mineral is dispersed in an organic polymer matrix, the gas diffusion path becomes long, and the effective cross-sectional area becomes small. Gas permeability can be reduced. That is, by including the clay mineral in the surface layer of the electrophotographic photosensitive member, the permeability of the oxidizing gas generated in the image forming process can be reduced, and deterioration of the constituent material of the electrophotographic photosensitive member can be suppressed. Can do. That is, the influence of the oxidizing gas can be reduced, and stable image formation can be realized over a long period of time.

  The clay mineral is not particularly limited and may be appropriately selected depending on the intended purpose, such as a smectite type clay mineral mainly composed of montmorillonite, hectorite, vermiculite, attapulgite, sepiolac, or a mixture thereof. Swellable clay minerals are used favorably. Among these, bentonite which is a clay mineral mainly composed of montmorillonite is preferable from the viewpoint of the characteristics of the electrophotographic photoreceptor.

In order to fully exhibit the effect of the clay mineral, the dispersion state of the clay mineral is important as will be described in the electrophotographic photoreceptor manufacturing method described later.
In order to realize the dispersed state of the clay mineral, it is effective to make the clay mineral organic.
The organic conversion method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a method of treating the clay mineral with an aliphatic organic cation.
The aliphatic organic cation functions as an organic agent that imparts an organic group to the clay mineral, and examples thereof include quaternary ammonium salts, phosphonium salts, and sulfonium salts. These may be used individually by 1 type and may use 2 or more types together. Among these, quaternary ammonium salts are preferable.
The quaternary ammonium salt is a cation in which four aliphatic groups are bonded to a nitrogen atom, and specifically includes alkyls such as trimethyloctylammonium, trimethyldodecylammonium, trimethyloctadecylammonium, and trimethylstearylammonium (TMS). Trimethylammonium ions; dimethyldialkylammonium ions such as dimethyldioctylammonium, dimethyldidodecylammonium, dimethyldioctadecylammonium (DMDO); trialkylmethylammonium ions such as trioctylmethylammonium and tridodecylmethylammonium; oleylbis (2-hydroxyethyl) ) Methylammonium (OHEM), and the like. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as said organic clay clay, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include Galamite (trade name, manufactured by Southern Clay Products), Viscogel (trade name, manufactured by Bentech), Orben (trade name, manufactured by Shiraishi Kogyo Co., Ltd.), Sven E, Organite T, S W, Esven N400, Esben NX, Esben NX80, Esben NO12S, Esben NO12, Esben NE (trade name, manufactured by Hojun Co., Ltd.), and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, sben NO12S obtained by organically treating bentonite using oleylbis (2-hydroxyethyl) methylammonium is particularly preferable.

  There is no restriction | limiting in particular in content in the said surface layer of the said clay mineral, Although it can select suitably according to the objective, 0.1 mass%-10 mass% are preferable, 1.0 mass%-5.0 The mass% is more preferable. When the content is less than 0.1% by mass, sufficient gas permeability is not exhibited, and an abnormal image may occur due to the influence of oxidizing gas or humidity. Side effects on the electrical characteristics of the photographic photoreceptor may increase, and image density may decrease due to an increase in the potential of the exposed area.

<< Other ingredients >>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a sensitizer, a dispersing agent, a hardening accelerator, surfactant, antioxidant, etc. are mentioned.

  The surface layer can be produced by the method for producing an electrophotographic photoreceptor of the present invention described later. There is no restriction | limiting in particular in the average thickness of the said surface layer, Although it can select suitably according to the objective, 0.5 micrometer-5 micrometers are preferable, and 0.5 micrometer-3 micrometers are more preferable.

<Support>
Examples of the support include those having a volume resistivity of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, indium oxide, etc. The metal oxide of the above is coated by film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc. After the conversion, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. An endless nickel belt or an endless stainless steel belt can also be used as a support.

In addition, those obtained by dispersing conductive powder in a suitable binder resin on the support can be used as the support.
There is no restriction | limiting in particular as said electroconductive powder, According to the objective, it can select suitably, For example, carbon powder, acetylene black; Metal powder, such as aluminum, nickel, iron, nichrome, copper, zinc, silver; Examples thereof include conductive tin oxide and metal oxide powders such as ITO.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester , Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl Examples thereof include carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like. These may be used individually by 1 type and may use 2 or more types together.
The conductive layer can be formed by applying a coating solution in which the conductive powder and the binder resin are dispersed in a solvent. Examples of the solvent include tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and the like.
Furthermore, 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, polytetrafluoroethylene-based fluororesin on a cylindrical substrate. Those provided with a conductive layer can also be used favorably as the support.

Among these, a cylindrical support made of aluminum that can be easily subjected to the anodized film treatment can be most preferably used. Here, the aluminum includes both pure aluminum and aluminum alloys. Specifically, JIS 1000 series, JIS 3000 series, JIS 6000 series aluminum, or aluminum alloy is mentioned.
The anodized film is obtained by anodizing various metals and various alloys in an electrolyte solution. Among these, a coating film called alumite obtained by anodizing aluminum or an aluminum alloy in an electrolyte solution is suitable for the photoreceptor. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative and positive development).
The anodizing treatment is performed, for example, in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. As an example of the sulfuric acid bath, for example, the sulfuric acid concentration is 10% by mass to 20% by mass, the bath temperature is 5 ° C. to 25 ° C., the current density is 1 A / dm ^{2 to} 4 A / dm ² , the electrolysis voltage is 5 V to 30 V, Examples of the processing time are 5 minutes to 60 minutes.

Since the anodic oxide film thus produced is porous and highly insulating, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is preferable to further seal the anodized film.
Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized water vapor. . Among these, a method of immersing in an aqueous solution containing nickel acetate is particularly preferable. Subsequent to the sealing treatment, an anodic oxide film is washed. The main purpose of the cleaning treatment is to remove excess metal salts and the like attached by the sealing treatment. If the metal salt or the like is excessively left on the surface of the support (anodized film), it not only adversely affects the quality of the coating film formed on the surface, but generally a low resistance component remains. It can also cause soiling.
The cleaning may be performed with pure water once, but usually, multi-step cleaning is performed. At this time, it is preferable that the final cleaning liquid is as clean as possible (deionized). Moreover, it is preferable to perform physical rubbing cleaning with a contact member in one of the multi-stage cleaning processes.

  The film thickness of the anodic oxide film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 μm to 15 μm. When the film thickness is less than 5 μm, the effect of the barrier property as an anodic oxide film may not be sufficient. When the film thickness exceeds 15 μm, the time constant as an electrode becomes too large, and the generation of residual potential or photoconductor Response may be reduced.

<Photosensitive layer>
The photosensitive layer may have any of a single layer structure and a laminated structure composed of a charge generation layer and a charge transport layer, but a photosensitive layer having a multilayer structure composed of a charge generation layer and a charge transport layer is particularly preferred.

<< Charge generation layer >>
The charge generation layer contains at least a charge generation material, preferably contains a binder resin, and further contains other components as necessary.

-Charge generation material-
The charge generation material is not particularly limited and may be appropriately selected depending on the intended purpose. However, as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. , Titanyl phthalocyanine having a maximum diffraction peak at least 27.2 ° can be preferably used. In particular, as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of the crystal type and CuKα described in Japanese Patent Laid-Open No. 2001-19871, the maximum diffraction is at least 27.2 °. It has a peak, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and 7.3 °. The titanyl phthalocyanine crystal having no peak between the peak of 9.4 ° and 9.4 ° is preferably used, and the crystal having no peak at 26.3 ° can be used effectively. Further, a titanyl phthalocyanine crystal having the above-mentioned crystal type, having an average particle size of 0.25 μm or less and free of coarse particles during crystal synthesis or by dispersion filtration (Japanese Patent Laid-Open Nos. 2004-83859 and 2004-2004). 78141) is useful.

  The charge generation layer is formed by dispersing the charge generation material in a solvent together with a binder resin, if necessary, using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, on the other layer such as a support or an intermediate layer. It is formed by applying to and drying.

-Binder resin-
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose.For example, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, Polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, Examples thereof include polyvinyl alcohol and polyvinyl pyrrolidone. These may be used individually by 1 type and may use 2 or more types together.
The content of the binder resin is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0 part by mass to 500 parts by mass with respect to 100 parts by mass of the charge generation material, and 10 parts by mass to 300 parts by mass is more preferable.

  The solvent is not particularly limited and may be appropriately selected depending on the intended purpose.For example, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, mono Examples include chlorobenzene, cyclohexane, toluene, xylene, ligroin, and the like. These may be used individually by 1 type and may use 2 or more types together.

The method for forming the charge generation layer using the charge generation layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a dip coating method, a spray coating method, a bead coating method, a nozzle Examples thereof include a coating method, a spinner coating method, and a ring coating method. After application, it is dried by heating in an oven or the like. There is no restriction | limiting in particular as said drying temperature, Although it can select suitably according to the objective, 50 to 60 degreeC is preferable.
There is no restriction | limiting in particular in the average thickness of the said charge generation layer, Although it can select suitably according to the objective, 0.01 micrometer-5 micrometers are preferable, and 0.1 micrometer-2 micrometers are more preferable.

<< Charge transport layer >>
The charge transport layer contains a charge transport material and a binder resin, and further contains other components as necessary.

-Charge transport material-
Examples of the charge transport material include a hole transport material and an electron transport material.
The hole transport material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include poly-N-vinylcarbazole or a derivative thereof, poly-γ-carbazolylethyl glutamate or a derivative thereof, and pyrene. -Formaldehyde condensate or derivative thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivative, oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, 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 may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as said electron transport material, According to the objective, it can select suitably, For example, chloranil, bromoanil, 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] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, benzoquinone derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.
The content of the charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 parts by mass to 300 parts by mass, and 40 parts by mass to 150 parts by mass with respect to 100 parts by mass of the binder resin. Part by mass is more preferable.

-Binder resin-
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester , Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinyl carbazole) ), Acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like. These may be used individually by 1 type and may use 2 or more types together.

-Polymer charge transport material-
For the charge transport layer, a polymer charge transport material having a function as the charge transport material and a function of the binder resin can also be suitably used. The charge transport layer composed of the polymer charge transport material is excellent in wear resistance.
The polymer charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose. A polycarbonate resin containing a triarylamine structure in at least one of the main chain and the side chain is used. Among these, polymer charge transport materials represented by any one of the following general formula (I) to the following general formula (X) are preferably used.

<General formula (I)>
However, in said general formula (I), R < ₁ >, R < ₂ >, R < ₃ > represents a substituted or unsubstituted alkyl group or a halogen atom each independently. R ₄ represents a hydrogen atom or a substituted or unsubstituted alkyl group. R ₅ and R ₆ represent a substituted or unsubstituted aryl group. o, p and q each independently represent an integer of 0 to 4, k and j represent a composition, and 0.1 ≦ k ≦ 1 and 0 ≦ j ≦ 0.9. n represents the number of repeating units and is an integer of 5 to 5,000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the general formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.
In the general formula, R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group, or halogen atom. l and m represent an integer of 0 to 4; Y represents a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —, —CO—, —CO—O. -Z-O-CO- (wherein Z represents an aliphatic divalent group) or a group represented by the following general formula. Here, R ₁₀₁ and R ₁₀₂ may be the same or different.
In the general formula, a is an integer of 1 to 20, b is an integer of 1 to _2,000, R _{103, R 104} represents a substituted or unsubstituted alkyl group or an aryl group. R ₁₀₃ and R ₁₀₄ may be the same or different.

<General formula (II)>
However, in said general formula (II), R <_7> , R < ₈ > represents a substituted or unsubstituted aryl group. Ar ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

<General formula (III)>
However, in said general formula (III), R <_9> , R < ₁₀ > represents a substituted or unsubstituted aryl group. Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

<General formula (IV)>
However, in said general formula (IV), R <_11> , R < ₁₂ > represents a substituted or unsubstituted aryl group. Ar ₇ , Ar ₈ and Ar ₉ represent the same or different arylene groups. p represents an integer of 1 to 5. X, k, j and n are the same as those in the general formula (I). In the general formula (IV), two copolymer species are described in the form of an alternating copolymer, but may be a random copolymer.

<General formula (V)>
However, in said general formula (V), R <_13> , R < ₁₄ > represents a substituted or unsubstituted aryl group. Ar ₁₀ , Ar ₁₁ , Ar ₁₂ represent the same or different arylene groups. X ₁ and X ₂ represent a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group. X, k, j and n are the same as those in the general formula (I). In the general formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

<General formula (VI)>
However, in said general formula (VI), R < ₁₅ >, R <_16> , R <_17> , R < ₁₈ > represents a substituted or unsubstituted aryl group. Ar ₁₃ , Ar ₁₄ , Ar ₁₅ and Ar ₁₆ represent the same or different arylene groups. Y ₁ , Y ₂ and Y ₃ represent 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 and a vinylene group, and are the same Or different. X, k, j and n are the same as those in the general formula (I). In the general formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

<General formula (VII)>
In the general formula _(VII), R _{19, R 20} is a hydrogen atom, a substituted or unsubstituted aryl _{group, R 19} and _{R 20} may form a ring. Ar ₁₇ , Ar ₁₈ , and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (VII), two copolymer species are described in the form of an alternating copolymer, but may be a random copolymer.

<General formula (VIII)>
However, in the general formula (VIII), R ₂₁ represents a substituted or unsubstituted aryl group. Ar ₂₀ , Ar ₂₁ , Ar ₂₂ and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (VIII), two copolymer species are described in the form of an alternating copolymer, but may be a random copolymer.

<General Formula (IX)>
However, in said general formula (IX), R < ₂₂ >, R <_23> , R <_24> , R < ₂₅ > represents a substituted or unsubstituted aryl group. Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , Ar ₂₈ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (IX), two copolymer species are described in the form of an alternating copolymer, but may be a random copolymer.

<General formula (X)>
However, in said general formula (X), R <_26> , R < ₂₇ > represents a substituted or unsubstituted aryl group. Ar ₂₉ , Ar ₃₀ , and Ar ₃₁ represent the same or different arylene groups. X, k, j and n are the same as those in the general formula (I). In the general formula (X), the two copolymer species are described in the form of an alternating copolymer, but may be a random copolymer.

As the polymer charge transporting material, in addition to the polymer charge transporting material described above, a monomer or oligomer having an electron donating group is formed at the time of film formation of the charge transporting layer, and a curing reaction or a crosslinking reaction is performed after the film formation. By doing so, the polymer finally having a two-dimensional or three-dimensional crosslinked structure is also included.
Furthermore, a charge transport layer having a crosslinked structure is also effectively used as the charge transport layer. Regarding the formation of a cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used to cause a cross-linking reaction using light or heat energy to form a three-dimensional network structure. is there. The three-dimensional network structure functions as a binder resin and exhibits high wear resistance.
Moreover, it is a very effective means to use a monomer having a charge transporting ability in whole or in part as the reactive monomer. By using such a monomer, a charge transport site is formed in the network structure, and the function as the charge transport layer can be sufficiently expressed. A reactive monomer having a triarylamine structure is effectively used as the monomer having charge transporting ability.
The charge transport layer having such a network structure has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and if it is too thick, cracks may occur. In this case, the charge transport layer is formed in a laminated structure, a low molecular dispersion polymer charge transport layer is used for the lower layer (charge generation layer side), and a charge transport layer having a crosslinked structure is formed on the upper layer (surface side). May be.
A charge transport layer composed of a polymer having these electron donating groups or a polymer having a crosslinked structure is excellent in wear resistance. Usually, in the electrophotographic process, since the charging potential (unexposed portion potential) is constant, if the surface layer of the photoreceptor is worn by repeated use, the electric field strength applied to the photoreceptor increases accordingly. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high abrasion resistance of the electrophotographic photosensitive member is advantageous against scumming. The charge transport layer composed of a polymer having these electron donating groups is a polymer compound, so it has excellent film-forming properties and has a charge transport site compared to a charge transport layer composed of a low molecular weight dispersed polymer. It can be configured with high density and has excellent charge transport capability. For this reason, a photoreceptor having a charge transport layer using a polymer charge transport material can be expected to have high-speed response.

  Examples of other polymers having an electron donating group include known monomer copolymers, block polymers, graft polymers, star polymers, and the like. Examples thereof include a crosslinked polymer having an electron donating group as disclosed in JP-A-3-109406, JP-A-2000-206723, JP-A-2001-34001, and the like.

  The charge transport layer is formed by applying a charge transport layer coating solution in which the charge transport material, the binder resin, and other components as necessary are dissolved or dispersed in a solvent, onto the charge generation layer, support, or intermediate layer. It can be formed by drying. You may add additives, such as a plasticizer, a leveling agent, antioxidant, a lubricant, to the said charge transport layer coating liquid as needed.

  The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone. These may be used individually by 1 type and may use 2 or more types together. Among these, non-halogen solvents are preferable from the intention of reducing environmental burdens, and cyclic ethers such as tetrahydrofuran, dioxolane, and dioxane; aromatic hydrocarbons such as toluene and xylene, or derivatives thereof are particularly preferable.

  There is no restriction | limiting in particular as said plasticizer, According to the objective, it can select suitably, For example, what is used as a plasticizer of common resins, such as a dibutyl phthalate and a dioctyl phthalate, etc. are mentioned. There is no restriction | limiting in particular in content of the said plasticizer, Although it can select suitably according to the objective, 0 mass%-30 mass% are preferable with respect to the said binder resin.

  The leveling agent is not particularly limited and may be appropriately selected depending on the intended purpose.For example, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, or An oligomer etc. are mentioned. The content of the leveling agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0% by mass to 1% by mass with respect to the binder resin.

The coating method of the charge transport layer coating solution is not particularly limited and can be appropriately selected depending on the purpose. For example, a dip coating method, a spray coating method, a bead coating method, a nozzle coating method, a spinner coating method, Ring coating method and the like. Among these, the dip coating method is preferable because the charge transport layer needs to be thickened to some extent.
The charge transport layer after the coating is formed is heated and dried by a heating means such as an oven. There is no restriction | limiting in particular in drying temperature, Although it can select suitably according to the objective, 80 to 200 degreeC is preferable and 110 to 170 degreeC is more preferable. There is no restriction | limiting in particular in drying time, Although it can select suitably according to the objective, 10 minutes or more are preferable and 20 minutes or more are more preferable.
The average thickness of the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 μm to 50 μm, more preferably 15 μm to 35 μm from the viewpoint of resolution and responsiveness.

<Single layer photosensitive layer>
The photosensitive layer having a single layer structure is a photosensitive layer in which a charge generation material and a charge transport material are dispersed or dissolved in a binder resin to realize a charge generation function and a charge transport function in one layer.

As for the charge transport material, binder resin, solvent and various additives used for the photosensitive layer having the single layer structure, any material contained in the charge generation layer and the charge transport layer can be used. is there.
The charge transport material preferably contains both the hole transport material and the electron transport material. A plasticizer, a leveling agent, an antioxidant and the like can be added as necessary.
As the binder resin, in addition to the binder resin mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. There is no restriction | limiting in particular in content of the said charge generation material with respect to 100 mass parts of said binder resins, Although it can select suitably according to the objective, 5 mass parts-40 mass parts are preferable, 10 mass parts-30 mass parts Is more preferable. The content of the charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0 part by mass to 190 parts by mass, and more preferably 50 parts by mass to 150 parts by mass.

The photosensitive layer having the single layer structure is a coating solution in which the charge generation material, the charge transport material, and the binder resin are dissolved or dispersed in a solvent such as tetrahydrofuran, dioxane, dichloroethane, methyl ethyl ketone, cyclohexane, cyclohexanone, toluene, xylene. Can be formed by using a dip coating method, a spray coating method, a bead coating method, a ring coating method or the like.
There is no restriction | limiting in particular in the average thickness of the photosensitive layer of the said single layer structure, Although it can select suitably according to the objective, 5 micrometers-40 micrometers are preferable, and 10 micrometers-30 micrometers are more preferable.

<< Intermediate layer >>
In the electrophotographic photoreceptor of the present invention, an intermediate layer can be provided between the support and the photosensitive layer (or the charge generation layer).
The intermediate layer contains at least a resin, and further contains other components as necessary.
The resin is preferably a resin having a high resistance to the solvent in consideration of applying the photosensitive layer on the intermediate layer with a solvent. The resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate; alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon. Resin; Examples include polyurethane, melamine resin, phenol resin, alkyd-melamine resin, epoxy resin, and other curable resins that form a three-dimensional network structure. These may be used individually by 1 type and may use 2 or more types together.

For example, fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the intermediate layer in order to prevent moiré and reduce residual potential. Furthermore, you may add a silane coupling agent, a titanium coupling agent, a chromium coupling agent, etc.
There is no restriction | limiting in particular in the said intermediate | middle layer, According to the objective, it can select suitably, It can form using a solvent and the apply | coating method. Further, as the intermediate layer, an anodized layer of Al ₂ O ₃ , an organic material such as polyparaxylylene (parylene), or an inorganic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, or CeO ₂ is used. What was provided by the vacuum thin film preparation method can also be used favorably.
There is no restriction | limiting in particular in the average thickness of the said intermediate | middle layer, Although it can select suitably according to the objective, 5 micrometers or less are preferable.

  In the electrophotographic photosensitive member, in order to improve environmental resistance, in particular, for the purpose of preventing a decrease in sensitivity and an increase in residual potential, a photogenerating layer, a charge transporting layer, an intermediate layer, a surface layer, and a single-layer photosensitizer Antioxidants, plasticizers, lubricants, ultraviolet absorbers, leveling agents and the like can be added to each layer such as a layer.

Here, the layer structure of the electrophotographic photosensitive member will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photosensitive member 201 of the present invention, which has a single-layer type photosensitive layer 207 and a surface layer 205 on a support 202.
FIG. 2 is a schematic cross-sectional view showing an example of another layer configuration of the electrophotographic photosensitive member 201 of the present invention, which has a charge generation layer 203, a charge transport layer 204, and a surface layer 205 on a support 202. ing.
FIG. 3 is a schematic cross-sectional view showing still another example of the layer structure of the electrophotographic photosensitive member 201 of the present invention. On the support 202, the intermediate layer 206, the charge generation layer 203, the charge transport layer 204, and the surface A layer 205 is included.

(Method for producing electrophotographic photoreceptor)
The method for producing an electrophotographic photoreceptor of the present invention is a method for producing the electrophotographic photoreceptor of the present invention,
It includes at least a surface layer forming step, and further includes other steps as necessary.

<Surface layer forming step>
The surface layer forming step is a step of forming a surface layer by applying a surface layer coating solution obtained by dispersing a clay mineral, an organic-inorganic hybrid material, and a curing agent in a solvent onto the photosensitive layer.

The surface layer coating solution contains the organic-inorganic hybrid material and the clay mineral, and the curing agent, and if necessary, a curing accelerator, a plasticizer, a leveling agent, and a low molecular charge transport material having no polymerizability. , And the like.
As the plasticizer, for example, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the content of the plasticizer is based on the total solid content of the surface layer coating solution. 20 mass% or less is preferable and 10 mass% or less is more preferable.
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. As for content of the said leveling agent, 3 mass% or less is preferable with respect to the total solid of a surface layer coating liquid.

The surface layer coating solution is diluted with a solvent as necessary. The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof 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; ether solvents such as tetrahydrofuran, dioxane and propyl ether; halogen solvents such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene; aromatic solvents such as benzene, toluene and xylene; methyl Cellosolve solvents such as cellosolve, ethyl cellosolve, cellosolve acetate and the like. These may be used individually by 1 type and may use 2 or more types together.
The dilution ratio with the solvent is appropriately selected depending on the solubility of the surface layer coating solution, the coating method, the target thickness, and the like.

The method for dispersing the surface layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a shaking device, ultrasonic dispersion, bead mill, ball mill, roll mill, homomixer, ultramixer, and disperser. Examples thereof include a mixer, a penetrating high-pressure dispersion device, a collision-type high-pressure dispersion device, a porous high-pressure dispersion device, an ultra-high pressure homogenizer, and an ultrasonic homogenizer.
Among these, applying mechanical force to the clay mineral to further promote the exfoliation or cleavage of the clay mineral promotes the dispersion of the clay mineral and brings it close to the exfoliated or cleaved dispersion state to the unit of nanometer order. In view of this, an ultrasonic homogenizer is particularly preferable.
In addition, when the surface layer coating solution is dispersed, it is preferable that the organic-inorganic hybrid material, the clay mineral, and the curing agent are simultaneously present. Thereby, when the organic-inorganic hybrid material and the curing agent enter between the layers of the clay mineral, a good dispersion state of the clay mineral can be realized, and the influence of the oxidizing gas can be further reduced.
There is no restriction | limiting in particular in the said application | coating, According to the objective, it can select suitably, For example, the dip coating method, the spray coat method, the bead coat method, the ring coat method etc. are mentioned.

  After the surface layer coating solution is applied, the surface layer is formed by applying energy from the outside to be polymerized. Examples of the external energy include heat, light, and radiation. Among these energies, those using heat and light energy are useful because of easy reaction rate control and simple apparatus.

  As the heat energy, heating is performed from the coating surface side or the support side using air, a gas such as nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. There is no restriction | limiting in particular as heating temperature, Although it can select suitably according to the objective, 80 to 170 degreeC is preferable. When the heating temperature is less than 80 ° C., the reaction rate is slow and the reaction may not be completed completely. When the heating temperature exceeds 170 ° C., the reaction proceeds non-uniformly and a large strain is generated in the surface layer. Sometimes. In order to advance the polymerization reaction uniformly, it is also effective to heat at a relatively low temperature of less than 50 ° C. and then heat to 100 ° C. or higher to complete the reaction.

There is no restriction | limiting in particular as light energy, According to the objective, it can select suitably, UV irradiation light sources, such as a high pressure mercury lamp and a metal halide lamp which have a light emission wavelength mainly in ultraviolet light, etc. are mentioned. A visible light source can be selected in accordance with the absorption wavelength of the polymerizable compound or photopolymerization initiator.
The amount of irradiation light is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 mW / cm ² or more, more preferably 500 mW / cm ² or more, and still more preferably 1,000 mW / cm ² or more. By using strong irradiation light with the irradiation light amount exceeding 1,000 mW / cm ² , the progress rate of the polymerization reaction is significantly increased, and a more uniform surface layer can be formed.
Examples of the energy of radiation include an electron beam.

<Other processes>
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a photosensitive layer formation process, an intermediate | middle layer formation process, etc. are mentioned.

<Process cartridge>
The process cartridge used in the present invention includes an electrophotographic photosensitive member, a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member using toner, and forms a visible image, a charging unit, and a cleaning unit. The electrophotographic photosensitive member of the present invention is used as the electrophotographic photosensitive member.
The process cartridge includes the electrophotographic photosensitive member of the present invention, and further includes at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit, and an image forming apparatus. It is a device (part) that is detachably attachable.

FIG. 4 shows an example of a process cartridge used in the present invention.
For example, as shown in FIG. 4, the process cartridge includes an electrophotographic photosensitive member 101 and includes a charging unit 112, a developing unit 114, a transfer unit 118, and a cleaning unit 123. In FIG. 4, reference numeral 113 denotes exposure from the exposure means, and 117 denotes a recording medium. As the electrophotographic photosensitive member 101, the electrophotographic photosensitive member of the present invention is used.

  Next, an image forming process using the process cartridge shown in FIG. 4 will be described. As the electrophotographic photosensitive member 101 rotates, an electrostatic latent image corresponding to the exposure image is formed on the surface by charging by the charging unit 112 and exposure 113 by the exposure unit (not shown). The electrostatic latent image is developed with toner by the developing unit 114, and the toner development is transferred to the recording medium 117 by the transfer unit 118 and printed out. Next, the surface of the electrophotographic photosensitive member 101 after the transfer is cleaned by the cleaning unit 123 and further discharged by the charge removing unit (not shown), and the above operation is repeated again.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes an electrophotographic photosensitive member, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a cleaning unit, and other units appropriately selected as necessary. It has.
As the electrophotographic photoreceptor, the electrophotographic photoreceptor of the present invention is used.
The image forming method used in the present invention includes an electrostatic latent image forming step, a developing step, a transfer step, and a cleaning step, and further includes other steps appropriately selected as necessary.

  The image forming method used in the present invention can be suitably implemented by the image forming apparatus used in the present invention, and the electrostatic latent image forming step can be performed by the electrostatic latent image forming unit, and the development The step can be performed by the developing unit, the transfer step can be performed by the transfer unit, the cleaning step can be performed by the cleaning unit, and the other steps can be performed by the other unit. it can.

<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 electrophotographic photosensitive member.
The electrophotographic photoreceptor of the present invention is used as the electrophotographic photoreceptor (sometimes referred to as “electrostatic latent image carrier” or “photoreceptor”).

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

The charging can be performed, for example, by applying a voltage to the surface of the electrophotographic photosensitive member using the charger.
The charger is not particularly limited and can be appropriately selected according to the purpose. And non-contact chargers using corona discharge such as corotrons and corotrons.

The shape of the charging means may take any form such as a magnetic brush or a fur brush in addition to a roller, and can be selected according to the specifications and form of the image forming apparatus. When a magnetic brush is used, the magnetic brush is composed of, for example, various ferrite particles such as Zn-Cu ferrite as a charging means, a nonmagnetic conductive sleeve for supporting the ferrite particle, and a magnet roll included in the nonmagnetic conductive sleeve. . Or, when using a brush, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal or metal oxide is used, and this is wound or attached to a metal or other conductive core. To make a charger.
The charger is not limited to the contact charger as described above. However, since an image forming apparatus in which ozone generated from the charger is reduced is obtained, a contact charger is used. preferable.

The exposure can be performed, for example, by exposing the surface of the electrophotographic photosensitive member imagewise using the exposure device.
The exposure device is not particularly limited as long as the surface of the electrophotographic photosensitive member charged by the charger can be exposed like an image to be formed, and can be appropriately selected according to the purpose. However, 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, an optical backside system that performs imagewise exposure from the backside of the electrophotographic photosensitive member may be employed.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using the toner or developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

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

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

<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 electrophotographic photosensitive member with the transfer charger using the visible image, 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 electrophotographic photosensitive member toward the recording medium. preferable. 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. A PET base or the like can also be used.

<Cleaning process and cleaning means>
The cleaning step is a step of removing the toner remaining on the electrophotographic photosensitive member, and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited as long as the toner remaining on the electrophotographic photosensitive member can be removed, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, a static cleaner Examples thereof include an electric brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

<Other processes and other means>
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a fixing process, a static elimination process, a recycling process, a control process, etc. are mentioned.
There is no restriction | limiting in particular as said other means, According to the objective, it can select suitably, For example, a fixing means, a static elimination means, a recycling means, a control means, etc. are mentioned.

-Fixing process and fixing means-
The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing unit, 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.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. 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.
There is no restriction | limiting in particular in the heating in the said heating-pressing means, According to the objective, it can select suitably, 80 to 200 degreeC is preferable.
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.

-Static elimination process and static elimination means-
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be suitably performed by a neutralization unit.
The neutralizing means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralizing bias to the electrophotographic photosensitive member. For example, a neutralizing lamp is preferably used. Can be mentioned.

-Recycling process and recycling means-
The recycling step is a step of recycling the toner removed by 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.

-Control process and control means-
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
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 sequencers and computers.

Next, the image forming apparatus of the present invention will be described with reference to the drawings. FIG. 5 is a schematic view showing an example of the image forming apparatus of the present invention.
In the image forming apparatus of FIG. 5, the electrophotographic photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape.
The charging roller 12, the transfer charger 18, and the separation charger 19 are not particularly limited and may be appropriately selected depending on the purpose. For example, besides the corotron, scorotron, and solid state charger (solid state charger) , Roller-shaped charging means, brush-shaped charging means, and the like.

As the charging means, a non-contact charging system such as corona charging or a contact charging system using a charging means using a roller or a brush is generally used, and any of them can be used effectively in the present invention. Among these, the charging roller 12 can significantly reduce the amount of ozone generated compared to corotron, scorotron, and the like, and is effective in stability during the repeated use of the photoreceptor and prevention of image quality deterioration.
However, since the electrophotographic photosensitive member 1 and the charging roller 12 are in contact with each other, the charging roller is contaminated by repeated use, which affects the photosensitive member and promotes the generation of abnormal images and a decrease in wear resistance. It is a cause. In particular, when a photoconductor having high wear resistance is used, it is difficult to perform reface due to surface wear, and therefore it is necessary to reduce the contamination of the charging roller.

Therefore, as shown in FIG. 6, by providing gap forming members 12a at both ends of the charging roller 12 and disposing them close to the photoreceptor 1 via the gap, contaminants are less likely to adhere to the charging roller 12, Or it becomes easy to remove and it is possible to reduce the influence.
In this case, the gap between the electrophotographic photosensitive member 1 and the charging roller 12 is preferably small. The gap is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 100 μm or less, and more preferably 50 μm or less.
However, by making the charging roller non-contact, discharge may become non-uniform and charging of the photoreceptor may become unstable. Such a problem is caused by maintaining the charging stability by superimposing the alternating current component on the direct current component, thereby making it possible to simultaneously reduce the influence of ozone, the charging roller contamination and the charging effect. .

Examples of the light source such as the exposure means 13 and the charge removal lamp 11 shown in FIG. All luminescent materials such as can be used. Among these, a semiconductor laser (LD) and a light emitting diode (LED) are preferable.
In order to irradiate only light in a desired wavelength range, for example, various 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.
The light source or the like provides the electrophotographic photosensitive member 1 with light by providing processes such as a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation together. However, the exposure of the electrophotographic photosensitive member 1 in the static elimination process has a great influence of fatigue on the electrophotographic photosensitive member 1, and may cause a decrease in charging or an increase in residual potential. Therefore, there is a case where it is possible to eliminate static electricity by applying a reverse bias in the charging process or cleaning process instead of static elimination by exposure, which may be effective from the viewpoint of enhancing the durability of the photoreceptor.

When the electrophotographic photoreceptor 1 is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photoreceptor. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner. A known method is applied to the developing means. Moreover, a well-known method is used also as a static elimination means.
As the transfer means, the above-described charger can be generally used. However, as shown in FIG. 5, a combination of the transfer charger 18 and the separation charger 19 is effective.
Further, the toner image is directly transferred from the electrophotographic photosensitive member 1 to paper using such a transfer unit. In the present invention, the toner image on the photosensitive member is transferred to the intermediate transfer member, and then the intermediate transfer member. The intermediate transfer method for transferring the toner to the paper is more preferable from the viewpoints of high durability and high image quality of the photoreceptor.
Among contaminants adhering to the surface of the photoconductor, discharge substances generated by charging, external additives contained in the toner, etc. easily pick up the influence of humidity and cause abnormal images. Paper dust is one of the causative substances of such abnormal images, and when they adhere to the photoconductor, not only abnormal images are likely to be generated, but also the wear resistance is reduced or biased. There is a tendency to cause wear. Therefore, it is more preferable from the viewpoint of high image quality that the photoconductor and the paper are not in direct contact for the above reason.

  The intermediate transfer method is particularly effective for an image forming apparatus capable of full-color printing. A plurality of toner images are once formed on the intermediate transfer member and then transferred to paper at a time to prevent color misregistration. It is easy to control and effective for high image quality. However, in the intermediate transfer method, since four scans are required to obtain one full-color image, the durability of the photosensitive member is a serious problem. Since the image blur hardly occurs even without a drum heater, the photoconductor is easy to use in combination with an intermediate transfer type image forming apparatus, and is particularly effective and useful. There are various materials or shapes such as a drum shape and a belt shape in the intermediate transfer member, but any of them can be used in the present invention. Effective and useful.

The toner developed on the electrophotographic photosensitive member 1 by the developing unit 14 shown in FIG. 5 is transferred to the recording medium 17, but not all is transferred, and the toner remaining on the electrophotographic photosensitive member 1 is not transferred. Also occurs.
Such residual toner is removed from the electrophotographic photosensitive member 1 by the cleaning brush 22 or the cleaning blade 23. The cleaning process may be performed only with a cleaning brush or may be performed in combination with a cleaning blade. As the cleaning brush, known ones such as a fur brush and a mag fur brush are used.
As described above, the cleaning step is a step of removing toner remaining on the electrophotographic photosensitive member 1 after the transfer, but the electrophotographic photosensitive member 1 is repeatedly rubbed by the cleaning blade 23 or the cleaning brush 22 or the like. When the electrophotographic photosensitive member 1 is accelerated in wear or scratched, an abnormal image may be generated.
Further, if the surface of the electrophotographic photosensitive member is contaminated due to poor cleaning, it not only causes an abnormal image, but also significantly reduces the life of the electrophotographic photosensitive member. In particular, in the case of an electrophotographic photosensitive member provided with a surface layer as the outermost surface layer for improving wear resistance, it is difficult to remove contaminants attached to the surface of the photosensitive member. Will be promoted. Therefore, improving the cleaning property of the electrophotographic photoreceptor 1 is very effective for improving the durability and image quality of the photoreceptor.

  As a means for improving the cleaning property of the electrophotographic photosensitive member 1, a method for reducing the coefficient of friction on the surface of the photosensitive member is known. Methods for reducing the coefficient of friction on the surface of the photoreceptor are classified into a method in which various lubricants are contained in the photoreceptor surface and a method in which the lubricant is supplied to the photoreceptor surface from the outside. The former is advantageous for small-diameter photoreceptors because of the high degree of freedom in layout around the engine, but the coefficient of friction increases remarkably with repeated use, and there remains a problem in its sustainability. On the other hand, the latter needs to be provided with a component for supplying a lubricating substance, but is effective for enhancing the durability of the photoreceptor because of high stability of the friction coefficient. Among them, the method of adhering to the photoreceptor during development by incorporating a lubricant into the developer is not restricted by the layout around the engine, and the effect of reducing the friction coefficient on the photoreceptor surface is high. Therefore, it is a very effective means for improving the durability and image quality of the photoreceptor.

There is no restriction | limiting in particular as said lubricity substance, According to the objective, it can select suitably, For example, Lubricating liquids, such as silicone oil and a fluorine oil; Various fluorine-containing resins, such as PTFE, PFA, PVDF; Silicone resin , Polyolefin resins, silicone grease, fluorine grease, paraffin wax, fatty acid esters, fatty acid metal salts such as zinc stearate; graphite, molybdenum disulfide, and the like. Among these, zinc stearate is particularly preferable because it is suitable for inclusion in the toner in powder form and has no adverse effect.
The content of the zinc stearate powder is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 0.5% by mass with respect to the toner, and 0.1% by mass. % To 0.3% by mass is more preferable.

  The electrophotographic photoconductor of the present invention can be applied to a small-diameter photoconductor because it can realize high photosensitivity and high stability. An image forming apparatus in which the photoconductor is used more effectively, or a method thereof, includes a plurality of electrophotographic photoconductors corresponding to each developing unit corresponding to a plurality of colors of toner, thereby performing parallel processing. It is very effectively used in a so-called tandem type image forming apparatus. The tandem image forming apparatus includes at least four color toners of yellow (C), magenta (M), cyan (C), and black (K) required for full-color printing and a developing unit that holds them. Further, by providing at least four electrophotographic photoreceptors corresponding to them, it is possible to perform full-color printing at an extremely high speed as compared with a conventional image forming apparatus capable of full-color printing.

FIG. 7 is a schematic view showing another example of the electrophotographic image forming apparatus of the present invention.
The belt-shaped electrophotographic photosensitive member 121 is provided with a photosensitive layer and a surface layer on a support. Driven by driving rollers 122a and 122b, charging by the charger 123, image exposure by the light source 124, development (not shown), transfer using the charger 125, exposure before cleaning by the light source 126, cleaning by the brush 127, and static elimination light source 128 The static elimination by is repeated.

The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and other embodiments are possible. For example, in FIG. 7, the pre-cleaning exposure is performed from the support side of the electrophotographic photosensitive member. However, the exposure may be performed from the photosensitive layer side of the electrophotographic photosensitive member, and irradiation of the static elimination light source may be performed on the electrophotographic photosensitive member. You may carry out from the support body side.
On the other hand, in FIG. 7, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. However, the pre-transfer exposure, the pre-exposure of image exposure, and other known light irradiation processes are provided. It is also possible to irradiate the photographic photoreceptor with light.

FIG. 8 is a schematic diagram showing an example of a tandem full-color image forming apparatus used in the present invention.
In FIG. 8, photoconductors 1C (cyan), 1M (magenta), 1Y (yellow), and 1K (black) are drum-like photoconductors, and these photoconductors 1C, 1M, 1Y, and 1K are illustrated in FIG. 8, charging means 12C, 12M, 12Y, and 12K, developing means 14C, 14M, 14Y, and 14K, and cleaning means 15C, 15M, 15Y, and 15K are arranged at least in the order of rotation.

  The charging means 12C, 12M, 12Y, and 12K constitute a charging means for uniformly charging the surface of the photoreceptor 1. Laser beams 13C, 13M, 13Y, and 13K from an exposure unit (not shown) are irradiated from the back side of the photoreceptor between the charging units 12C, 12M, 12Y, and 12K and the developing units 14C, 14M, 14Y, and 14K. Thus, electrostatic latent images are formed on the photoreceptors 1C, 1M, 1Y, and 1K.

  Then, four image forming elements 10C, 10M, 10Y, and 10K centering on the photoreceptors 1C, 1M, 1Y, and 1K are juxtaposed along a conveyance belt 25 that is a recording medium conveyance unit. The conveyor belt 25 is provided between the developing units 14C, 14M, 14Y, and 14K of the image forming units (elements) 10C, 10M, 10Y, and 10K and the cleaning units 15C, 15M, 15Y, and 15K, and the photoreceptors 1C, 1M, and 15K. Transfer brushes 26 </ b> C, 26 </ b> M, 26 </ b> Y, and 26 </ b> K for applying a transfer bias are disposed on a surface (back surface) that is in contact with 1 </ b> Y and 1 </ b> K and that contacts the back side of the conveyance belt 25 on the photoconductor side. The image forming elements 10C, 10M, 10Y, and 10K have the same configuration except that the color of the toner inside the developing unit is different.

In the tandem full-color image forming apparatus shown in FIG. 8, the image forming operation is performed as follows.
First, in each of the image forming elements 10C, 10M, 10Y, and 10K, the photosensitive members 1C, 1M, 1Y, and 1K rotate in the direction indicated by the arrow in FIG. Next, an electrostatic latent image corresponding to each color image to be created is formed by laser light 13C, 13M, 13Y, and 13K by exposure means (not shown) disposed outside the photosensitive member. .

  Next, the latent image is developed by the developing means 14C, 14M, 14Y, and 14K to form a toner image. Developing means 14C, 14M, 14Y, and 14K are developing means for developing with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. The toner images of the respective colors created on 1Y and 1K are superimposed on the recording medium 17. The recording medium 17 is sent out from the tray by a paper feed roller 24, temporarily stopped by a pair of registration rollers 16, and sent to the transfer conveyance belt 25 in synchronism with the image formation on the photosensitive member. The recording medium 17 held on the conveyor belt 25 is conveyed, and the toner images of each color are transferred at the contact positions (transfer portions) with the photoreceptors 1C, 1M, 1Y, 1K.

The toner image on the photosensitive member is transferred onto the recording medium 17 by an electric field formed by a potential difference between the transfer bias applied to the transfer brushes 26C, 26M, 26Y, and 26K and the photosensitive members 1C, 1M, 1Y, and 1K. The Then, the recording medium 17 on which the four color toner images are superimposed through the four transfer portions is conveyed to the fixing means 27, where the toner is fixed, and is discharged to a discharge portion (not shown). Further, the residual toner that remains on the photoreceptors 1C, 1M, 1Y, and 1K without being transferred by the transfer unit is collected by the cleaning units 15C, 15M, 15Y, and 15K.
In FIG. 8, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the recording medium conveyance direction. However, the order is not limited to this order, and the color order is arbitrarily set. Also, when creating a black-only document, it is effective to provide a mechanism that stops the image forming elements 10C, 10M, and 10Y other than black.

Further, in FIG. 8, the charging means is in contact with the photosensitive member, but by using the charging roller 12 as shown in FIG. 6, an appropriate gap (about 10 μm to 200 μm) can be provided between them. It is preferable from the viewpoint that both wear amounts can be reduced and toner filming to the charging roller can be reduced.
The image forming means as described above may be fixedly incorporated in the copying apparatus, facsimile, or printer, but may be incorporated in the image forming apparatus in the form of a process cartridge.

Since the tandem image forming apparatus can transfer a plurality of toner images at a time, high-speed full-color printing is realized. However, since at least four electrophotographic photosensitive members are required, an increase in the size of the image forming apparatus is unavoidable, and depending on the amount of toner used, there is a difference in the amount of wear of each photosensitive member. There have been many problems such as poor color reproducibility and abnormal images.
On the other hand, the electrophotographic photoreceptor of the present invention can be applied to a photoreceptor having a small diameter by realizing high photosensitivity and high stability, and the influence of residual potential rise, sensitivity deterioration, and the like is reduced. Even if the usage amounts of the four electrophotographic photoreceptors are different, the difference in residual potential and sensitivity over time is small, and it is possible to obtain a full-color image with excellent color reproducibility even after repeated use over a long period of time. .

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
-Production of electrophotographic photoreceptor-
On an aluminum cylinder (JIS 1050) having a length of 340 mm and a diameter of 30 mm, an intermediate layer coating solution having the following composition was applied, followed by drying at 130 ° C. for 20 minutes to form an intermediate layer having an average thickness of 3.5 μm.
Next, on the intermediate layer, a charge generation layer coating solution having the following composition was applied, followed by drying at 130 ° C. for 20 minutes to form a charge generation layer having an average thickness of 0.2 μm.
Next, on the charge generation layer, a charge transport layer coating solution having the following composition was applied, followed by drying at 130 ° C. for 20 minutes to form a charge transport layer having an average thickness of 25 μm.
Next, a surface layer coating solution having the following composition dispersed using an ultrasonic homogenizer was applied onto the charge transport layer, followed by drying at 150 ° C. for 60 minutes to form a surface layer having an average thickness of 1.3 μm. Thus, the electrophotographic photosensitive member of Example 1 was produced. The intermediate layer coating solution, the charge generation layer coating solution, and the charge transport layer coating solution were all applied using a blade coating method, and the surface layer coating solution was applied using a spray coating method.

<Intermediate layer coating solution>
Titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) ... 50 parts by mass Alkyd resin (Beckolite M6401-50, solid content 50% by mass, manufactured by DIC Corporation) 15 parts by mass Melamine resin (L-145-60, solid content 60% by mass, manufactured by DIC Corporation) 8 parts by mass 2-butanone 120 parts by mass

<Charge generation layer coating solution>
・ Asymmetric bisazo pigment represented by the following structural formula: 2.5 parts by mass
・ Polyvinyl butyral (“XYHL”, manufactured by UCC): 0.5 mass part ・ Methyl ethyl ketone: 110 mass part ・ Cyclohexanone: 260 mass part

<Charge transport layer coating solution>
Polycarbonate (Z Polyca, manufactured by Teijin Chemicals Ltd.): 10 parts by mass Charge transport compound represented by the following structural formula: 7 parts by mass
・ Tetrahydrofuran ... 80 parts by mass Silicone oil (KF50-100cs, manufactured by Shin-Etsu Chemical Co., Ltd.) ... 0.002 parts by mass

<Preparation of surface layer coating solution>
The following composition was dispersed under the following conditions using an ultrasonic homogenizer (Sonics & Materials, VC-750) to prepare a surface layer coating solution.
-Dispersion condition-
・ Distributed output: 50%
・ Dispersion time: 3 minutes ・ Pulse control: ON 1 second / OFF 1 second [Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composeran E102, epoxy resin-4 functional silica hybrid) ... 100 parts by mass ・ Clay mineral (Hojun Co., Ltd., Organized Bentonite, Sven NO12S) ... 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 2)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photosensitive member of Example 2 was produced in the same manner as Example 1 except that the composition of the surface layer coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composeran E102B, epoxy resin-4 functional silica hybrid) ... 100 parts by mass 3 parts by mass-Curing agent (Mitsui Chemical Fine Co., Ltd., metaphenylenediamine) ... 12 parts by mass-Methyl ethyl ketone ... 1,400 parts by mass

(Example 3)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photosensitive member of Example 3 was produced in the same manner as Example 1 except that the composition of the surface layer coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composelan E103A, epoxy resin-3 functional silica hybrid) ... 100 parts by mass ・ Clay mineral (Hojun Co., Ltd., Organized bentonite, Sven NO12S) ... 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 4)
-Production of electrophotographic photoreceptor-
In Example 1, the electrophotographic photoreceptor of Example 4 was produced in the same manner as in Example 1 except that the composition of the surface layer coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composeran E103D, epoxy resin-3 functional silica hybrid) ... 100 parts by mass ・ Clay mineral (Hojun Co., Ltd., organic bentonite, Sven NO12S) ... 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 5)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photoreceptor of Example 5 was produced in the same manner as in Example 1 except that the composition of the surface layer coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composelan E201, epoxy resin-3 functional silica hybrid) ... 50 parts by mass ・ Clay mineral (Hojun Co., Ltd., Organized Bentonite, Sven NO12S) ... 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 6)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photosensitive member of Example 6 was produced in the same manner as in Example 1 except that the composition of the surface coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Industries, Composeran E202C, epoxy resin-4 functional silica hybrid) ... 50 parts by mass 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 7)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photosensitive member of Example 7 was produced in the same manner as Example 1 except that the composition of the surface layer coating solution was changed as follows.
[Composition of surface layer coating solution]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composelan E202C, epoxy resin-4 functional silica hybrid) ... 50 parts by mass Clay mineral (Coop Chemical Co., Ltd., lipophilic smectite, SEN) ... 3 parts by mass ・ Curing agent (manufactured by Shin Nippon Chemical Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass (JER Co., EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass Methyl ethyl ketone ... 1,400 parts by mass

(Example 8)
-Production of electrophotographic photoreceptor-
In Example 1, the surface layer coating liquid was dispersed in the following composition excluding the curing agent and the accelerator, and the same as in Example 1 except that the curing agent and the accelerator having the following composition were added after the dispersion was completed. Thus, an electrophotographic photosensitive member of Example 8 was produced.
[Composition of surface layer coating solution during dispersion]
・ Organic-inorganic hybrid material (Arakawa Chemical Co., Ltd., Composelan E102, Epoxy resin-4 functional silica hybrid) ... 100 parts by mass 3 parts by mass ・ Methyl ethyl ketone ... 1,400 parts by mass [curing agent and accelerator added after dispersion is completed]
・ Curing agent (manufactured by Shin Nippon Rika Co., Ltd., Ricacid MH-700, 4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 (mass ratio)) 23 parts by mass ・ Accelerator (JER Corporation) EMI24, 2-ethyl-4 (5) -methylimidazole) ... 4 parts by mass

Example 9
-Production of electrophotographic photoreceptor-
An electrophotographic photosensitive member of Example 9 was produced in the same manner as in Example 1 except that the average thickness of the surface layer was 0.3 μm in Example 1.

(Example 10)
-Production of electrophotographic photoreceptor-
An electrophotographic photosensitive member of Example 10 was produced in the same manner as in Example 1 except that the average thickness of the surface layer was 0.5 μm in Example 1.

(Example 11)
-Production of electrophotographic photoreceptor-
An electrophotographic photosensitive member of Example 11 was produced in the same manner as in Example 1 except that the average thickness of the surface layer was 2 μm in Example 1.

(Example 12)
-Production of electrophotographic photoreceptor-
An electrophotographic photosensitive member of Example 12 was produced in the same manner as in Example 1 except that the average thickness of the surface layer was 3 μm in Example 1.

(Example 13)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photosensitive member of Example 13 was produced in the same manner as Example 1 except that the average thickness of the surface layer was 5 μm.

(Example 14)
-Production of electrophotographic photoreceptor-
In Example 1 above <Preparation of surface layer coating solution>, except that the surface layer coating solution was prepared by dispersing by stirring using a magnetic stirrer and stirrer without using an ultrasonic homogenizer. Similarly, an electrophotographic photosensitive member of Example 14 was produced.

(Comparative Example 1)
-Production of electrophotographic photoreceptor-
An electrophotographic photosensitive member of Comparative Example 1 was produced in the same manner as in Example 1, except that the surface layer was not provided and the average thickness of the charge transport layer was 27 μm.

(Comparative Example 2)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photoreceptor of Comparative Example 2 was produced in the same manner as in Example 1 except that the organic-inorganic hybrid material was removed from the composition of the surface layer coating solution.

(Comparative Example 3)
-Production of electrophotographic photoreceptor-
In Example 1, an electrophotographic photoreceptor of Comparative Example 3 was produced in the same manner as in Example 1 except that the clay mineral was removed from the composition of the surface layer coating solution.

<Evaluation>
The produced electrophotographic photosensitive members of Examples 1 to 14 and Comparative Examples 1 to 3 are mounted on a process cartridge as shown in FIG. 4, and a tandem type full color image forming apparatus as shown in FIG. 8 (manufactured by Ricoh Co., Ltd., imagio). MPC3000), the exposure light source is a 655 nm semiconductor laser (image writing by a polygon mirror), a scorotron charger is used as a charging means, a transfer belt is used as a transfer means, and a 655 nm LED is used as a static elimination light source. went. The results are shown in Table 1.

<< Measurement of surface potential of unexposed part and exposed part of photoreceptor >>
The process conditions before the test were set as follows, and the surface potential of the unexposed part and the exposed part of the electrophotographic photosensitive member were measured. As a measuring method, a surface potential meter (Model 344, manufactured by Trek Japan Co., Ltd.) is mounted at the developing unit position of the tandem type full color image forming apparatus as shown in FIG. The surface area potential of the unexposed area and the surface area of the exposed area at the development position were measured.
-Pre-test process conditions-
-Electrostatic photosensitive member charging potential (unexposed portion potential): -700 V
・ Development bias: -500V

<< Afterimage >>
The A4 size chart in which the character part and halftone part shown in FIG. evaluated.
〔Evaluation criteria〕
A: Extremely good B: Good C: Normal D: Somewhat inferior E: Very inferior

The above evaluation was performed before and after exposure to NOx gas shown under the following conditions. These results are shown in Table 1.
-NOx gas exposure conditions-
・ Equipment: NOx exposure test equipment manufactured by Dailek ・ Nitric oxide concentration: 50 ppm
・ Nitrogen dioxide concentration: 50ppm
・ Temperature: 35 ℃
・ Relative humidity: 55%
・ Exposure period: 3 days

<Real machine accelerated fatigue evaluation>
The produced electrophotographic photosensitive members of Examples 1 to 14 and Comparative Examples 1 and 3 are mounted on the process cartridge shown in FIG. 4 and a tandem full-color image forming apparatus as shown in FIG. 8 (image Ricoh Co., Ltd., imagio MPC3000). The following evaluation was performed using a 655 nm semiconductor laser (image writing by a polygon mirror) as an exposure light source, a scorotron charger as a charging means, a transfer belt as a transfer means, and a 655 nm LED as a static elimination light source. The results are shown in Table 2.
The process conditions before the test were set as follows. As a sheet passing condition, a chart with a writing rate of 6% (characters equivalent to 6% as an image area is written on the entire A4 size surface), the contact pressure of the cleaning blade and the electrophotographic photosensitive member is used. The applied bias to the charging means and the amount of light of the semiconductor laser were set so that the amount of passing charge of the toner was twice the pre-test process conditions, and continuous 30,000 sheets were printed.
-Pre-test process conditions-
Photoconductor charging potential (unexposed portion potential): -700V
・ Development bias: -500V

<Measurement of unexposed surface potential and exposed surface potential of electrophotographic photoreceptor>
The unexposed portion surface potential and the exposed portion surface potential of the electrophotographic photosensitive member before and after printing 30,000 sheets were measured. As a measuring method, a surface potential meter (Model 344, manufactured by Trek Japan Co., Ltd.) is mounted at the developing unit position of the image forming apparatus shown in FIG. The bias was fixed, and the unexposed surface potential and the exposed surface potential at the development position were measured.

<Abrasion amount of photoreceptor>
The difference (wear amount) in the film thickness of the electrophotographic photosensitive member before and after all tests was measured. Except for 5 cm at both ends in the longitudinal direction of the electrophotographic photosensitive member, the film thickness of the electrophotographic photosensitive member was measured at an interval of 1 cm by FISCHERSCOPE MMS manufactured by Fischer Instruments Co., Ltd., and the average value was taken as the film thickness.

<Dirt on the skin>
After printing 30,000 sheets, one white image was output, and the presence or absence of dirt on the background portion of the electrophotographic photosensitive member was visually observed, and evaluated according to the following four criteria.
〔Evaluation criteria〕
◎: Extremely good ○: Good △: Slightly inferior ×: Very bad

<Color color reproducibility (color balance)>
After printing 30,000 sheets, an ISO / JIS-SCID image N1 (portrait) was output, and color color reproducibility was evaluated in the following four stages.
〔Evaluation criteria〕
◎: Extremely good ○: Good △: Slightly inferior ×: Very bad

From the results of Table 2, Examples 1 to 14 show extremely stable electrical characteristics even after printing 30,000 sheets, have good image characteristics such as background stains and color balance, and have a small amount of wear on the surface layer. I understood.
From the above results, in the examples, good results were obtained, the electrical characteristics were extremely stable, the mechanical durability was high, the afterimage did not occur due to the influence of the oxidizing gas, and the results were extremely high. It has been found that an electrophotographic photoreceptor having reliability can be obtained.

As an aspect of this invention, it is as follows, for example.
<1> A support, and a photosensitive layer and a surface layer on the support,
The electrophotographic photoreceptor, wherein the surface layer contains an organic-inorganic hybrid material and a clay mineral.
<2> The electrophotographic photosensitive member according to <1>, wherein the organic-inorganic hybrid material is an epoxy resin-silica hybrid material.
<3> The electrophotographic photosensitive member according to any one of <1> to <2>, wherein the organic-inorganic hybrid material is an epoxy resin-4 functional silica hybrid material.
<4> The electrophotographic photoreceptor according to any one of <1> to <3>, wherein the clay mineral is an organic bentonite that has been organically treated with an organic agent.
<5> The electrophotographic photosensitive member according to any one of <1> to <4>, wherein the surface layer contains a curing agent, and the curing agent is an acid anhydride.
<6> The electrophotographic photosensitive member according to any one of <1> to <5>, wherein the surface layer has an average thickness of 0.5 μm to 3 μm.
<7> The method for producing an electrophotographic photosensitive member according to any one of <1> to <6>,
An electrophotography comprising a surface layer forming step of forming a surface layer by applying a surface layer coating solution obtained by dispersing a clay mineral, an organic-inorganic hybrid material, and a curing agent in a solvent onto the photosensitive layer. This is a method for producing a photoreceptor.
<8> The method for producing an electrophotographic photosensitive member according to <7>, wherein the dispersion in the surface layer coating solution is performed using an ultrasonic homogenizer.
<9> an electrophotographic photoreceptor;
An electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image to a recording medium;
Cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member from the surface of the electrophotographic photosensitive member after transfer,
An electrophotographic photosensitive member according to any one of <1> to <6>, wherein the electrophotographic photosensitive member is an image forming apparatus.
<10> An electrophotographic photosensitive member, a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member using a toner to form a visible image, a charging unit, a cleaning unit, a transfer unit, and a neutralizing unit A process cartridge having at least one means selected from
A process cartridge, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of <1> to <6>.

DESCRIPTION OF SYMBOLS 1, 1C, 1M, 1Y, 1K Electrophotographic photosensitive member 101 Electrophotographic photosensitive member 201 Electrophotographic photosensitive member 202 Support body 203 Charge generation layer 204 Charge transport layer 205 Surface layer 206 Intermediate layer 207 Single-layer photosensitive layer

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 JP 2004-302450 A JP 2005-107490 A JP 2006-71856 A Japanese Patent No. 4785648 JP 2000-66425 A JP 2006-99028 A JP 2006-11014 A JP 2006-208996 A JP 2003-76237 A

Claims (9)

A support, and a photosensitive layer and a surface layer on the support;
The electrophotographic photoreceptor, wherein the surface layer contains an organic-inorganic hybrid material and a clay mineral.   The electrophotographic photosensitive member according to claim 1, wherein the organic-inorganic hybrid material is an epoxy resin-silica hybrid material.   The electrophotographic photosensitive member according to claim 1, wherein the organic-inorganic hybrid material is an epoxy resin-4 functional silica hybrid material.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the clay mineral is an organic bentonite that has been organically treated with an organic agent.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer contains a curing agent, and the curing agent is an acid anhydride.   The electrophotographic photosensitive member according to claim 1, wherein the average thickness of the surface layer is 0.5 μm to 3 μm. A method for producing an electrophotographic photosensitive member according to any one of claims 1 to 6,
An electrophotography comprising a surface layer forming step of forming a surface layer by applying a surface layer coating solution obtained by dispersing a clay mineral, an organic-inorganic hybrid material, and a curing agent in a solvent onto the photosensitive layer. A method for producing a photoreceptor.   The method for producing an electrophotographic photosensitive member according to claim 7, wherein the dispersion in the surface layer coating solution is performed using an ultrasonic homogenizer. An electrophotographic photoreceptor;
An electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image to a recording medium;
Cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member from the surface of the electrophotographic photosensitive member after transfer,
An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1.