JP2003066634A - Coating device for organic photoreceptor, method for coating and organic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device and a method for coating an organic photoreceptor by which solvent vapor can be discharged as uniformly as possible near a cylindrical conductive base body, a nonhalogen solvent having low saturation vapor pressure at about normal temperature is used, and even when a charge transfer layer of a thick coating film is applied, the solvent can be uniformly discharged, irregularity in the film thickness is avoided and a thin film part at the top of the body is made short, and to provide an organic photoreceptor obtained by the above method for coating. SOLUTION: In the coating device for an organic photoreceptor by dipping a plurality of cylindrical conductive base bodies in a coating liquid at a time and drawing up to form a coating film on each cylindrical conductive base body, the device is equipped with a coating tank which houses the coating liquid for charge transfer layer using a nonhalogen solvent and with a plurality of drying hoods disposed above the coating tank in the positions corresponding to the respective cylindrical conductive base bodies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating device for an organic photoreceptor, a coating method, and an organic photoreceptor manufactured by the coating method. In particular, in the production of an organic photoreceptor, an organic material is formed on the outer peripheral surface of a cylindrical conductive substrate. The present invention relates to a coating device for forming a photosensitive layer, a coating method, and an organic photoconductor manufactured by the coating method.

[0002]

2. Description of the Related Art Heretofore, as a photoconductive material constituting a photosensitive layer of an electrophotographic photosensitive member, inorganic compounds such as selenium, cadmium sulfide and zinc oxide and organic compounds represented by polyvinylcarbazole have been proposed. In the laminated organic photoreceptor in which the photosensitive layer is separated into a charge generating layer and a charge transporting layer, as the charge generating material and the charge transporting material,
Various organic compounds have been proposed and put into practical use as organic photoconductors. Conventionally, as a coating method for such an organic photoreceptor, a dip coating method, a spray coating method, a spin coating method,
Bead coating method, wire bar coating method, blade coating method,
Various coating methods such as a roller coating method, an extrusion coating method, and a curtain coating method are known. Particularly, as a method for forming a uniform photosensitive layer on the outer peripheral surface of a cylindrical conductive substrate, a dip coating method is widely used. Has been.

In recent years, downsizing of devices such as copiers, printers and facsimiles using organic photoconductors has been proposed.
There is a strong demand for weight reduction, and along with this, the diameter of organic photoconductors is being reduced year by year. As a method for producing an organic photoconductor, particularly an organic photoconductor using a small-diameter cylindrical conductive substrate by a dip coating method, from the viewpoint of improving productivity, JP-A-5-88385 and JP-A-6-262113. As described in the publication, a multiple simultaneous dip coating method in which a plurality of cylindrical conductive substrates are simultaneously dipped in a coating solution and pulled up is generally adopted. In particular, if the space between the cylindrical conductive substrates is narrowed, the productivity is further increased, which is advantageous. At that time, the solvent vapor generated from the coating film formed when the cylindrical conductive substrate is pulled up, or the coating tank. Due to the influence of solvent vapor generated from the liquid surface, the touch-drying speed of the coating film formed on the cylindrical conductive substrate is non-uniform between the cylindrical conductive substrates and within one cylindrical conductive substrate. And film thickness unevenness occurs. As a workaround,
As described in JP-A-59-127049, etc., when the cylindrical conductive substrate is not pulled up from the liquid level of the coating tank, air is sent from the outside to the vicinity of the liquid receiving tank, and from the vicinity of the liquid receiving tank. An ON-OFF mechanism in which a solvent vapor discharge port is provided in the vicinity of a liquid receiving tank, as described in JP-A-3-151, etc., in which the solvent vapor concentration is reduced in advance to accelerate the touch drying speed. The unevenness of the film thickness is suppressed by controlling the solvent vapor concentration around the cylindrical conductive substrate at the time of pulling up from the liquid level of the coating tank by connecting to the forced exhaust device provided with.

However, in the above technique, the solvent vapor concentration is low near the air supply port and around the cylindrical conductive substrate in the vicinity of the solvent vapor discharge port connected to the forced evacuation device, but it is high in the distant place. Therefore, it was difficult to make the solvent vapor concentration uniform.

That is, the conventional workaround for the problem that the solvent vapor concentration around the cylindrical conductive substrate becomes non-uniform during dip coating is not sufficient. In the prior art as described above, the solvent vapor concentration on the coated surface of the cylindrical conductive substrate varies depending on the location, which causes unevenness in drying of the coated surface, resulting in uneven coating film thickness.

As a measure for avoiding the non-uniformity of the solvent vapor concentration, for example, as shown in JP-A-8-220786, the solvent vapor is placed in the middle of the recycle pipe and at a position lower than the liquid level of the coating tank. A method has been proposed in which a solvent having a specific gravity higher than that of air and a relatively low saturated vapor pressure is used to uniformize the solvent vapor concentration on the liquid surface of the coating tank by using a coating device provided with an outlet. However, with this method, the drying hood on the coating tank is filled with a solvent with a low saturated vapor pressure, and the drying speed tends to be slow, until touch-drying (becomes non-greasy to the touch with fingers) is reached. In addition, the coating film easily flows, the coating film at the coating tip becomes thin, the leading thin film becomes long, and uneven film thickness easily occurs. In particular,
In the case of coating a charge transport layer having a large coating thickness (thickness containing a large amount of solvent immediately after coating), unevenness in the thickness and increase of the leading thin film are likely to occur before touch-drying is reached.

On the other hand, as a coating solvent for an organic photoreceptor, a halogen solvent has been widely used because of its good solubility of a binder and a charge transporting substance. In recent years, however, a halogen solvent has been feared because of the fear of destroying the global environment. The use of is being regulated more and more year by year. Therefore, dioxolane, dioxane, etc. have been proposed as a solvent instead of the halogen solvent. However, when a large number of simultaneous coatings by a conventional apparatus were performed using these solvents, unevenness in the film thickness and the increase of the leading film thickness were remarkable. It was found. It is considered that this is because these solvents have a low vapor pressure at a normal application temperature and a long drying time until touch drying.

[0008]

Therefore, the present invention has been made for the purpose of solving the above-mentioned problems in the prior art. That is, the object of the present invention is to discharge the solvent vapor generated from the coating film formed when the cylindrical conductive substrate is pulled up and the solvent vapor evaporated from the liquid surface of the coating tank as uniformly as possible around the cylindrical conductive substrate. An organic photoconductor that can uniformly discharge the solvent even when a non-halogen solvent having a low saturated vapor pressure at around room temperature is used and a charge transport layer having a large coating thickness is applied, has a small thickness unevenness, and has a short leading thin film It is to provide a coating device. Another object of the present invention is to provide a method for coating an organic photoconductor, which is capable of forming a photosensitive layer or the like on a cylindrical conductive substrate using the coating apparatus, and the coating method. An object is to provide an organophotoreceptor manufactured by using the method.

[0009]

The above object of the present invention can be achieved by the following constitution.

1. In an organic photoreceptor coating apparatus in which a plurality of cylindrical conductive substrates are simultaneously immersed in a coating liquid and pulled up to form a coating film on the cylindrical conductive substrates, the coating apparatus uses a non-halogen solvent-based charge. An apparatus for coating an organophotoreceptor, comprising: a coating tank containing a transport layer coating solution; and a drying hood on the coating tank corresponding to each of a plurality of cylindrical conductive substrates.

2. In the dry hood, the gap width between the hood and the cylindrical conductive substrate when passing through the cylindrical conductive substrate is set to 1/10 to 1 in terms of the diameter ratio of the cylindrical conductive substrate. 1. The organic photoreceptor coating apparatus according to 1.

3. 3. The organic photoreceptor coating apparatus according to 1 or 2 above, wherein the dry hood has a large number of ventilation holes.

4. One of the ventilation holes has an opening diameter of 0.1 to
The coating device for an organic photosensitive member as described in 3 above, wherein the coating device has a diameter of 10 mmφ.

5. 5. The organic photoreceptor coating apparatus according to 3 or 4 above, wherein the opening area ratio of the entire ventilation holes (with respect to the total area of the dry hood) is 5 to 50%.

6. 6. The organophotoreceptor coating apparatus according to any one of 1 to 5 above, wherein the non-halogen solvent is a cyclic ether.

7. 7. The organophotoreceptor coating apparatus according to any one of 1 to 6 above, wherein the cyclic ether is at least one selected from dioxolane, dioxane, and tetrahydrofuran.

8. Using the coating apparatus according to any one of 1 to 7 above, a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution and pulled up to form a charge transport layer on the cylindrical conductive substrate. A method for applying an organic photoreceptor characterized by the above.

9. The coating thickness of the charge transport layer is 30 to 3
9. The method for applying an organic photoreceptor as described in 8 above, wherein the coating method is 00 μm.

10. An organic photoreceptor prepared by using the method for applying an organic photoreceptor as described in 8 or 9 above.

The present invention will be described in detail below. FIG. 1 shows a schematic configuration of an example of the multiple simultaneous dip coating apparatus of the present invention, showing a state in which a cylindrical conductive substrate is being pulled up from a coating liquid. In FIG. 1, a solvent vapor storage chamber 11 for preventing the influence of an external air flow is provided on the coating tank 6, and an individual drying hood 14 is provided above the solvent vapor storage chamber 11. ing. When the cylindrical conductive substrate is pulled up from the coating tank 6, the cylindrical conductive substrate enters the solvent vapor reservoir chamber 14 where the coating film releases a large amount of solvent vapor and is sent to an individual drying hood 14 to be dried. In the present invention, it is preferable to provide the discharge port 12 between the solvent vapor storage chamber 11 and the drying hood 14. By providing the outlet 12,
Even when a solvent having a high saturated vapor pressure is used as the coating liquid, the solvent vapor concentration in the solvent vapor reservoir chamber 11 can be maintained uniform throughout, and uneven touch-drying of the coating film does not occur.

Here, the solvent vapor reservoir covers the coating tank,
This is a room for temporarily stagnating the solvent vapor generated from the coating liquid or coating film and maintaining an atmosphere with a uniform solvent vapor concentration. The outlet is formed between the solvent vapor reservoir and the drying hood so as to surround the cylindrical conductive substrate when the coated substrate is pulled up. The dry hood has a structure surrounding the cylindrical conductive substrate.

On the other hand, the coating liquid 1 is pumped from the coating liquid tank 2 through the supply pipe 3 by the pump 4, and is supplied into the coating tank 6 through the filter 5. A mesh 15 is inserted in the lower part of the coating tank 6 in order to obtain uniform coating liquid flow velocity in the tank. The coating liquid supplied into the coating tank 6 overflows and is collected in the coating liquid receiving tank 7 provided at the lower end of the solvent vapor reservoir 11 at the upper part of the coating tank 6 to be recycled.
And is collected in the coating liquid tank 2. When performing dip coating using this dip coating device, the cylindrical conductive substrate 9
Is immersed in the coating tank 6 and then, when it is pulled up, the coating solution is circulated by a circulation means so as to always overflow in order to keep the coating tank liquid surface 10 constant.

Conventionally, when a large number of cylindrical conductive substrates are coated at the same time, the drying hood provided on the coating tank 6 also serves as the solvent vapor reservoir chamber as shown in FIG. An apparatus having a structure in the middle of the recycle pipe 8, that is, a structure in which all of a large number of substrates are surrounded by a large dry hood 14 (hereinafter also referred to as a large dry hood) has been used, but in this structure, the dry hood 14 is used. It was difficult to uniformly reduce the solvent vapor concentration in the solution, and it was difficult to uniformly reduce the solvent vapor concentration around each substrate, which tended to cause unevenness of the film thickness and increase of the leading thin film. In particular, when a charge transport layer of a thick coating film was formed using a cyclic ether solvent such as dioxolane, dioxane and tetrahydrofuran, this tendency was remarkable.

In the present invention, as shown in FIG. 1, the solvent vapor reservoir chamber and the drying hood are separated, and the drying hood is provided for each individual cylindrical conductive substrate, so that the drying conditions between the cylindrical conductive substrates are uniform. And, by uniformly lowering the solvent vapor concentration in the dry hood, by using a cyclic ether solvent having a relatively slow drying rate such as dioxolane, dioxane and tetrahydrofuran, even if the charge transport layer of a thick coating film is applied, It is possible to prevent the unevenness of the film thickness and the increase of the leading thin film, and reduce the characteristic variations among the respective photoconductors.

The dry hood preferably has a cylindrical shape sufficient to allow the cylindrical conductive substrate to pass therethrough.
That is, the gap width (H in FIG. 1) between the hood of the dry hood and the cylindrical conductive substrate is 1/1 in terms of the diameter ratio of the cylindrical conductive substrate.
It is preferable to set it to 0-1. The diameter ratio is 1/10
When the ratio is less than 1, the dry hood and the substrate are likely to come into contact with each other when passing through the cylindrical conductive substrate, and a trouble such as scraping of the coating film is likely to occur. On the other hand, even if the diameter ratio is larger than 1, the device becomes large in size. Therefore, it does not contribute to the improvement of productivity. The opening diameter of each ventilation hole is preferably 0.1 to 10 mm. 0.1 mm
If it is less than 10, solvent vapor tends to stay in the dry hood, and 10
If it is larger than mm, the inside of the dry hood is easily disturbed by the outside air.

It is also preferable that the dry hood has a large number of ventilation holes. The overall opening area ratio of the ventilation holes (with respect to the total area of the dry hood) is preferably 5 to 50%. If it is less than 5%, solvent vapor tends to stay in the dry hood, and if it is more than 50%, the environment inside the dry hood is easily disturbed by the outside air.

The length of the dry hood is 5 cm to 300 c.
m is preferred. When it is less than 5 cm, the effect of the dry hood is small, and the effect of preventing the occurrence of uneven film thickness is small. While 300
Even if it is larger than cm, the effect commensurate with the increase in size of the device cannot be obtained.

In the present invention, it is preferable to have a solvent vapor storage chamber below the drying hood and above the coating tank, but the distance from the coating liquid surface of the drying hood is preferably between 1 cm and 100 cm. That is, if it is less than 1 cm, the space of the solvent vapor storage chamber becomes narrow, and the coating film immediately after coating cannot be stabilized.
Further, even if it is larger than 100 cm, the effect commensurate with the increase in size of the apparatus cannot be obtained.

Further, in the present invention, it is preferable to provide an exhaust port between the solvent vapor reservoir chamber and the drying hood. That is, by providing an outlet just above the solvent vapor reservoir chamber, the solvent vapor is not directly sucked into the drying hood that follows it, so that the concentration of solvent vapor in the drying hood can be lowered and the finger of the coating film can be reduced. Touch drying can be accelerated, and even in the case of a charge transport layer coating film using a cyclic ether solvent having a relatively low drying speed, it is possible to prevent unevenness in film thickness and increase of the leading thin film. still,
The above-mentioned cyclic ether solvent is most preferable as the non-halogen solvent for the charge transport layer of the present invention, but a mixed solvent of the cyclic ether and another non-halogen solvent can also be preferably used. For example, a good effect can be obtained by mixing a cyclic ether solvent and an alcohol solvent, a ketone solvent, an aromatic solvent, or the like.

The discharge port 12 is preferably installed with a gap width of 0.1 to 10 mm between the solvent vapor storage chamber and the drying hood. If it is less than 0.1 mm, the amount of solvent vapor discharged is not sufficient, and if it is 10 mm or more, the amount of solvent vapor discharged is sufficient,
The solvent vapor storage chamber is easily affected by the flow of external air, and the solvent vapor concentration uniformity in the solvent vapor storage chamber is easily disturbed.

The upper lid portion of the solvent vapor storage chamber is provided with an opening (hole) necessary for passing the cylindrical conductive substrate. The opening is preferably circular like the cylindrical conductive substrate.

The drying condition of the dry hood is preferably natural drying. Since the coating film in the drying hood is in a state immediately after coating, if the drying air is forcedly fed, the film thickness unevenness and the leading thin film are increased.

Further, in order to form a coating film on the outer peripheral surfaces of a plurality of cylindrical conductive substrates at the same time, it is preferable that the coating and drying conditions of the respective substrates are made uniform, and the coating positions of the cylindrical conductive substrates are arranged at each other. An arrangement method that does not make a difference is preferable. As a method for arranging such a substrate, the method for arranging the four-layer simultaneous coating apparatus shown in FIG. 3 is preferable.

In the present invention, the organic photoconductor is an electrophotographic photoconductor having an organic compound having one of the charge generating function and the charge transporting function, which are indispensable for the construction of the electrophotographic photoconductor. This means that it includes all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or an organic charge transporting material and a photoreceptor composed of a polymer complex having a charge generating function and a charge transporting function.

The organic photoreceptor of the present invention has a charge generation layer and a charge transport layer on a cylindrical conductive substrate, but a layer structure in which an intermediate layer is provided between the cylindrical conductive substrate and the charge generation layer is more preferable. Hereinafter, the layer structure of the organic photoreceptor preferably used in the present invention will be described.

Cylindrical Conductive Substrate The cylindrical conductive substrate means a cylindrical substrate required to form an image endlessly by rotating and has a straightness of 0.1 mm or less and a shake of 0.1 mm or less. Conductive substrates in the range are preferred. When the circularity and the shake range are exceeded, good image formation becomes difficult.

As the conductive material, a metal drum of aluminum, nickel or the like, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. As a conductive substrate, the specific resistance is 1 at room temperature.
It is preferably 0 ³ Ωcm or less.

The electroconductive substrate used in the present invention may have a surface on which a sealed alumite film is formed. Alumite treatment is usually, for example, chromic acid,
It is carried out in an acidic bath of sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing in sulfuric acid gives the most favorable results. In the case of anodizing treatment in sulfuric acid,
It is preferable that the sulfuric acid concentration is 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is about 20 V, but the present invention is not limited thereto. The average thickness of the anodized film is usually 20μ.
m or less, and particularly preferably 10 μm or less.

Intermediate layer In the present invention, a resin layer formed by the reaction of an organic resin or an organometallic compound between the conductive substrate and the photosensitive layer,
Alternatively, it is preferable to provide an intermediate layer in which semiconductor particles such as titanium oxide are dispersed in an organic resin. By providing such an intermediate layer, it is possible to prevent entry of free charges from the conductive substrate. The thickness of the intermediate layer is preferably 0.1 to 20 μm.

Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention may be a single-layer photosensitive layer structure in which one layer has a charge generating function and a charge transporting function on the intermediate layer, but it is more preferable that the photosensitive layer is photosensitive. It is preferable that the function of the layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, the charge generation layer (C
GL) and a charge transport layer (CTL) thereon. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging. The most preferable photosensitive layer structure of the present invention is a negatively charged photosensitive member structure having the above-mentioned function separation structure.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below. Charge Generation Layer The charge generation layer contains a charge generation material (CGM). If necessary, a binder resin and other additives may be contained as other substances.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azurenium pigment or the like can be used. Among these, CGM that can minimize the increase in residual potential with repeated use
Has a steric structure and a potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specific examples thereof include a phthalocyanine pigment and a perylene pigment CGM having a specific crystal structure. For example, the Bragg angle 2θ with respect to Cu-Kα rays
CGMs such as titanyl phthalocyanine having a maximum peak at 27.2 ° and benzimidazole perylene having a maximum peak at 22.4 at 27.2 have almost no deterioration due to repeated use, and the residual potential increase can be reduced.

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is a formal resin, a butyral resin, a silicone resin, a silicone-modified butyral resin, or a phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The dry film thickness of the charge generation layer is preferably 0.01 μm to 2 μm.

Charge Transport Layer The charge transport layer of the present invention means a layer containing at least a charge transport substance. As long as the charge-transporting substance has a function of transporting holes or electrons generated from the charge-generating substance, any known or new organic compound can be used.

The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing CTM to form a film.
Other substances may optionally contain additives such as antioxidants.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, CTM that can minimize the increase in residual potential due to repeated use has high mobility and has a characteristic that the difference in ionization potential with CGM to be combined is 0.5 (eV) or less, and preferably 0. It is 0.25 (eV) or less.

The ionization potentials of CGM and CTM are measured by a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) are polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-
Examples include polymer organic semiconductors such as N-vinylcarbazole.

The most preferred binder for these CTLs is a polycarbonate resin. Polycarbonate resin is most preferable in improving dispersibility of CTM and electrophotographic characteristics. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The dry film thickness of the charge transport layer is preferably 10 to 40 μm.

Protective Layer The organic photoreceptor of the present invention may be provided with a protective layer forming a surface layer having a low surface energy. For example, a protective layer of a siloxane-based resin layer, a protective layer containing a fluorine-based resin, or the like may be provided on the photosensitive layer.

In the above, the most preferable layer constitution of the photosensitive member of the present invention is exemplified, but in the present invention, a photosensitive member layer constitution other than the above may be adopted.

The coating solution for producing each layer constituting the organic photoreceptor of the present invention requires a solvent capable of dissolving the components of each layer. The present invention is characterized by using a non-halogen solvent as the solvent for the charge transport layer, but it is preferable to use a non-halogen solvent for each of the other layers. Examples of these non-halogen solvents include various solvents such as alcohols and ketones, but dioxolane, dioxane and tetrahydrofuran are particularly preferable as the coating liquid solvent for the charge transport layer of the present invention. These solvents have excellent solubility of the known charge generating substance and the binder resin of the charge generating layer,
It is also extremely excellent in terms of environmental load on the global environment.

Further, the coating apparatus or the coating method of the present invention can be suitably applied to the formation of the undercoat layer and the charge generation layer of the organic photoreceptor. However, particularly when the coating method of the present invention is applied to the charge transport layer in which the coating film thickness exceeds 100 μm and the unevenness of the film thickness and the occurrence of the leading thin film are large, good results are obtained.

As described above, the charge transport layer is formed on a large number of cylindrical conductive substrates using the apparatus of the present invention, so that the solvent can be dried while keeping the condition of touch-drying immediately after dip coating even between the individual substrates. Can be discharged out of the system. As a result, the coating film thickness (coating film thickness including the solvent immediately after coating) was 30 to 300 μm.
Even in the charge transport layer of m, the unevenness of the film thickness can be reduced.

The saturated vapor pressure at room temperature is 1.3 to 40 kP.
Even if a cyclic ether solvent such as dioxolane, dioxane, or tetrahydrofuran having a relatively low drying rate of a is used, the effect of improving the unevenness in film thickness can be maintained.

[0056]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 An intermediate layer was formed on a cylindrical conductive substrate as follows.

Polyamide resin CM8000 (manufactured by Toray)
1 part by mass and 10 parts by mass of methanol were added to the same container and dissolved and dispersed to prepare an intermediate layer coating liquid 1. The intermediate layer coating solution was applied to the independent dry hood of FIG. 1 (each dry hood has a large number of vent holes of 3 mmφ, and the opening area ratio of the vent holes is 25
%) And a cylindrical aluminum substrate (1.0 mmt × 30 mmφ × 340 m)
m). The coating liquid temperature at that time was 24 ° C. The speed of pulling up the aluminum substrate from the coating solution is 4
It was set to 80 mm / min. As the position of the outlet 12,
1m gap width between the solvent vapor reservoir and the drying hood shown in Fig. 1.
It is installed at m. The outlet is 10c from the liquid level of the coating tank.
It is formed with a circle of 50 mm at a height of m. The coating liquid circulation flow rate was 5 L / min, and the diameter of the recycle pipe 8 was 150 mmφ. Each coated substrate was air-dried through a 15 cm dry hood, then placed in a drier at 70 ° C.
In 10 minutes, it heat-dried and formed the 0.1-micrometer-thick intermediate | middle layer.

Next, 60 parts by mass of Y-type titanyl phthalocyanine and a silicone-modified butyral resin (manufactured by Shin-Etsu Chemical Co., Ltd.)
700 parts by mass and 2-butanone 2000 parts by mass are mixed,
It was dispersed for 10 hours using a sand mill to prepare a charge generation layer coating liquid. This coating solution was subjected to the above-mentioned operation by using a four simultaneous dip coating apparatus having independent dry hoods (each drying hood has a large number of vent holes of 3 mmφ and the opening area ratio of the vent holes is 25%) in FIG. It was applied onto the aluminum substrate on which the intermediate layer obtained in Example 1 was formed, and dried at 70 ° C. for 10 minutes to form a charge generation layer having a film thickness of 0.2 μm. The speed of pulling up the aluminum substrate from the coating solution was 240 mm / min. The coating liquid temperature at that time is 24
℃ was made. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor storage chamber and the drying hood shown in FIG. The outlet is 50 cm at a height of 10 cm from the surface of the coating tank.
It is formed by a circle of mm. The circulating flow rate of the coating solution is 5
L / min, the diameter of the recycle tube 8 was 150 mmφ.

On the above-mentioned charge generation layer, four simultaneous immersions having independent dry hoods of FIG. 1 (each dry hood has a large number of vent holes of 3 mmφ and the opening area ratio of the vent holes is 25%) The charge transport layer was applied using an applicator. Charge transport material [N- (4-methylphenyl) -N- {4-
225 parts by mass of (β-phenylstyryl) phenyl} -p-toluidine], 300 parts by mass of polycarbonate (viscosity average molecular weight 20,000), 6 parts by mass of antioxidant (Exemplary compound 1-3), and 2000 parts by mass of dioxolane are mixed. Then, it was dissolved to prepare a charge transport layer coating solution. This coating liquid was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a coating film thickness of 95 μm and a dry film thickness of 20 μm.
The speed of pulling up the aluminum substrate from the coating solution is 240
mm / min. The coating liquid temperature at that time was 24 ° C. As the position of the discharge port 12, a gap width of 1 mm is installed between the solvent vapor storage chamber and the drying hood shown in FIG.
The discharge port is formed as a circle of 50 mm at a height of 10 cm from the liquid level of the coating tank. The coating liquid circulation flow rate is 1 L / m.
In, the diameter of the recycling pipe was 100 mmφ.
The coated aluminum substrate was air-dried via a 15 cm dry hood and then placed in a dryer at 90 ° C.
It was heated and dried for 60 minutes to form a charge transport layer, and an organic photosensitive drum was produced. Table 1 shows the film thickness unevenness values of the four films at that time. Here, the film thickness unevenness value is the maximum value and the minimum value of the film thickness values of 4 points (90 ° intervals) in the circumferential direction at each of 20 mm, 50 mm, 160 mm and 300 mm from the upper end of the coating film, for a total of 16 points. It is the difference. The results are shown in Table 1.

Comparative Example 1 For comparison, a cylindrical dry conductive substrate was prepared under the same conditions as in Example 1 except that the large dry hood shown in FIG. 2 (the discharge port was in the middle of the recycling pipe) was used. The coating operation of the intermediate layer, the charge generation layer, and the charge transport layer was performed. The results are shown in Table 1.
Shown in.

[0062]

[Table 1]

Example 2 Except that the distance between the discharge ports 12 was set to 8 mm and the solvent for the charge transport layer coating solution was changed from dioxolane to dioxane.
Table 1 shows the results of coating the charge transport layer on the charge generation layer under the same conditions as in Example 1.

Example 3 The charge transport layer was formed on the charge generation layer under the same conditions as in Example 1 except that the distance between the discharge ports 12 was 0.2 mm and the solvent for the charge transport layer coating solution was changed from dioxolane to tetrahydrofuran. The layers were applied. The results are shown in Table 1.

Further, the leading thin film of each of the photoconductors of Examples 1 to 3 and Comparative Example 1 was evaluated. The results are shown in Table 2. * Evaluation of the leading thin film An arbitrary straight line is selected along the drum axis of the cylindrical photoreceptor. The film thickness of the photosensitive layer is measured at regular intervals of 10 mm from the leading portion of the coating on the straight line, and a photosensitive layer film thickness profile as shown in FIG. 4 is created. The length L of the leading thin film is defined as the length a from the drum tip of the photoconductor to the intersection of the tangent of the leading portion thickness rise and the extension of the saturated thickness. The length of the leading thin film was measured for each photoconductor, and the results are shown in Table 2.
The film thickness measuring device is a photodetection type film thickness measuring device MCPD-100.
0 (instantaneous multi-photometric detector: Otsuka Electronics Co., Ltd.) was used.

[0066]

[Table 2]

As can be seen from Tables 1 and 2, a coating device in which an independent hood corresponding to a plurality of cylindrical conductive substrates is provided on a coating tank in which a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution. The organic photoconductor having an intermediate layer, a charge generation layer, and a charge transport layer formed by using is significantly improved in both thickness unevenness and length of the leading thin film as compared with the case of using a comparative large dry hood. Is found to have been done.

[0068]

As is apparent from the above-mentioned embodiments, the use of the organic photoreceptor coating apparatus and coating method of the present invention
The photosensitive layer formed on each cylindrical conductive substrate can have a small thickness unevenness, and the length of the leading thin film can be made small. Therefore, it is possible to provide a cylindrical organic photosensitive member with good performance. Is.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an example of a multiple simultaneous dip coating apparatus of the present invention.

FIG. 2 is a diagram of a coating device using a large-sized dry hood.

FIG. 3 is a diagram of an arraying method of four simultaneous coating devices.

FIG. 4 is a view showing a film thickness profile of a photosensitive layer.

[Explanation of symbols]

1 coating liquid 2 Coating liquid tank 3 supply piping 4 pumps 5 filters 6 coating tanks 7 Coating liquid receiving tank 8 recycling pipes 9 Cylindrical conductive substrate 10 Liquid level of coating tank (overflow surface) 11 Solvent vapor reservoir 12 outlet 14 Dry hood 15 mesh

Continued front page    F-term (reference) 2H068 EA14 EA16                 4D075 AB02 AB33 AB36 AB52 AB56                       AB60 CA48 DA15 DA20 DB01                       DB07 DB18 DB31 DC19 DC24                       EA07 EA45 EB14 EB15 EB16                       EB19 EB22 EB32 EB33 EB35                       EB36 EB38 EB39 EB43 EC30                 4F040 AA07 AB06 AC01 BA42 CC09                       CC13 DB27                 4F042 AA03 AA06 AA10 BA03 BA25                       CA01 CB02 CB20 DE01 DE09

Claims (10)

[Claims] 1. An organic photoreceptor coating apparatus in which a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution and pulled up to form a coating film on the cylindrical conductive substrates, wherein the coating apparatus is a non-halogen compound. An apparatus for coating an organic photoreceptor, comprising: a coating tank containing a coating liquid for a charge transport layer using a solvent; and a drying hood corresponding to each of a plurality of cylindrical conductive substrates on the coating tank. 2. The dry hood is configured such that a gap width between the hood and the cylindrical conductive substrate when passing through the cylindrical conductive substrate is 1/10 to 1 in terms of a diameter ratio of the cylindrical conductive substrate. The coating device for an organic photoreceptor according to claim 1. 3. The apparatus for coating an organic photoconductor according to claim 1, wherein the drying hood has a large number of ventilation holes. 4. One of the ventilation holes has an opening diameter of 0.1 to 1.
The coating device for an organic photoreceptor according to claim 3, wherein the coating device has a diameter of 0 mmφ. 5. The apparatus for coating an organic photoconductor according to claim 3, wherein an opening area ratio of the entire ventilation holes (to an area of the entire drying hood) is 5 to 50%. 6. The apparatus for coating an organophotoreceptor according to claim 1, wherein the non-halogen solvent is a cyclic ether. 7. The organophotoreceptor coating apparatus according to claim 1, wherein the cyclic ether is at least one selected from dioxolane, dioxane, and tetrahydrofuran. 8. Using the coating apparatus according to claim 1, a plurality of cylindrical conductive substrates are simultaneously immersed in a coating solution and then pulled up to form a charge on the cylindrical conductive substrate. A method for coating an organic photoreceptor, which comprises forming a transport layer. 9. The coating thickness of the charge transport layer is 30 to 30.
The coating method for an organic photoreceptor according to claim 8, wherein the coating thickness is 0 μm. 10. An organic photoconductor manufactured by using the method for coating an organic photoconductor according to claim 8.