JP2020190649A - Method of manufacturing electrophotographic photoreceptor - Google Patents

Abstract

To remove foreign matter from a coating liquid for charge transport layer in manufacturing an electrophotographic photoreceptor, and then to provide a process cartridge having the obtained electrophotographic photoreceptor.SOLUTION: A coating liquid is passed through a ceramic filter which is rotating, or a centrifugal separator to remove foreign matter.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing an electrophotographic photosensitive member. The present invention relates to a process cartridge and an electrophotographic apparatus having an electrophotographic photosensitive member obtained from such a manufacturing method.

As an electrophotographic photosensitive member used in an electrophotographic image forming apparatus, an electrophotographic photosensitive member having a photosensitive layer containing an organic charge generating substance and a charge transporting substance on a support is known.

In the production of the electrophotographic photosensitive member, a dipping coating device and a circulation system for removing foreign matter from the coating liquid in the coating tank and returning the foreign matter to the coating tank are often used. The immersion coating device includes a coating tank that houses the coating liquid and an elevating device that grips the support of the electrophotographic photosensitive member, immerses it in the coating liquid in the coating tank, and pulls it up.

Further, in recent years, with the demand for higher resolution and higher definition of the electrophotographic image forming apparatus, the demand for image defects called white spots and black spots has become stricter.

Specifically, when the support is immersed and coated, foreign matter brought into the coating liquid from the support or the like is introduced. This foreign matter is contained in the coating film and causes an image of poor latent image when forming an electrophotographic image. As a result, a phenomenon called white spots and a phenomenon called black spots that result in poorly charged images occur.

Such foreign matter is often dealt with by providing a filter in a part of the device that circulates the coating liquid.

Patent Document 1 describes that a filter is provided in the path portion to filter unnecessary substances that cause coating defects such as foreign matter defects.

Japanese Unexamined Patent Publication No. 2011-25196

According to the studies by the present inventors, the electrophotographic photosensitive member described in Patent Document 1 does not have sufficient countermeasures against coating film defects for outputting high-resolution and high-definition images, and there is room for improvement. ..

An object of the present invention is a method for producing an electrophotographic photosensitive member that does not cause image defects caused by foreign substances in a paint when outputting a high-resolution and high-definition image, and an electrophotographic photosensitive member obtained thereby. To provide.

Therefore, the present invention
A method for manufacturing an electrophotographic photosensitive member in which a charge transport layer is provided by applying a coating liquid on a support and drying the support.
Provided is a method for producing an electrophotographic photosensitive member, which comprises a step of removing a foreign substance having a particle size of 5 nm or more from the coating liquid by a rotating ceramic filter or a centrifuge.

According to the present invention, there is provided a method for producing an electrophotographic photosensitive member that prevents image defects caused by foreign substances in a paint when outputting a high-resolution and high-definition image, and an electrophotographic photosensitive member obtained thereby. can do.

It is a schematic diagram of the process cartridge which concerns on this embodiment.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

As a result of examination by the present inventors, when a coating liquid having a particularly high viscosity is used, if the pore size of the filter is reduced in order to reduce the size of foreign matter, the flow rate is reduced and the desired liquid passing amount cannot be obtained. I found out.

On the other hand, the present inventor has found that a desired liquid flow rate can be obtained by using a rotary ceramic filter or a centrifuge.

The rotary ceramic filter filters a liquid containing foreign matter in a state where a disk-shaped filter (disc filter) is rotated.

The liquid passes through the holes in the filter and foreign matter is collected there. The remaining liquid collects in the center of the disk-shaped filter and is discharged from there to the outside of the filter. The center has a filtrate flow path connected to the rotation axis of the disk-shaped filter.

Since it has a disk structure, a filtration (flow path) area can be secured. Specifically, the disc has a honeycomb structure. The disc diameter is about φ150 mm and several hundred mm (for example, 300 mm), and the hole diameter can be appropriately selected from, for example, 5 nm to 2000 nm. The ceramic is in the form of a film, for example, TiO2, MgAl2O, ZrO2, Al2O3, or the like. The rotation speed is, for example, about 0 to several thousand rpm (for example, 1000 rpm). Therefore, foreign matter having a particle size of 5 nm or more can be filtered.

By rotating at high speed, the foreign matter adhering to the surface of the filter medium is peeled off by the shearing force, and it is possible to suppress the foreign matter from accumulating on the surface of the filter medium as a cake and prevent an increase in filtration resistance.

In addition, although the centrifuge is different from filtration, it is not necessary to consider changes in the size of foreign matter and the filtration performance of the filter medium over time.

By using the rotary ceramic filter and the centrifuge in this way, a desired liquid flow rate can be obtained. More specifically, the amount of liquid passing through can be increased.

The viscosity of the coating liquid is not particularly limited, but when the viscosity is 30 mPa · s or more and 500 mPa · s or less, it is preferable in terms of the takt time for producing the electrophotographic photosensitive member, and more preferably 50 mPa · s or more and 300 mPa · s or less.

This liquid passing may be a flow of liquid when an unused coating liquid (coating liquid that has not undergone immersion coating) is supplied to the coating tank. Alternatively, it may be the flow of the liquid in the circulation system for taking out the coating liquid in the coating tank that has been used once or more and returning it to the coating tank again.

Specifically, the circulation system is a flow path such as a pipe, and the coating liquid may be discharged from the coating tank and returned to the coating tank again. In that case, a filtration device or a centrifuge having a rotary ceramic filter may be connected to the circulation system.

Alternatively, the circulatory system is an aggregate of the coating tank and another device (that is, a filtration device or a centrifuge having a rotary ceramic filter) that is not connected to the coating tank by a pipe, in addition to the flow path. It may be a system in which the coating liquid of the above can be regenerated and returned to the coating tank again.

In the present invention, the coating liquid can be circulated through a flow path such as a pipe or pumped out between the immersion coating device and the filtration device having the rotating ceramic filter connected to the immersion coating device or the centrifuge. Can be circulated.

[Electrophotophotoreceptor]
The electrophotographic photosensitive member of the present invention has a charge transport layer.

The charge transport layer may be a photosensitive layer together with the charge generating layer, and as described in the single-layer type photosensitive layer described later, when the photosensitive layer has a charge generating substance and a charge transporting substance, the photosensitive layer is used. It may be called a charge transport layer.

Examples of the method for producing the electrophotographic photosensitive member of the present invention include a method in which a coating liquid for each layer described later is prepared, applied in the order of desired layers, and dried. The charge transport layer is obtained by dip coating and drying of the coating film, and the coating methods for obtaining other layers include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, and curtain. Examples include coating, wire bar coating, and ring coating.

Hereinafter, each layer will be described.

<Support>
In the present invention, the electrophotographic photosensitive member has a support. In the present invention, the support is preferably a conductive support having conductivity. Further, examples of the shape of the support include a cylindrical shape, a belt shape, and a sheet shape. Above all, a cylindrical support is preferable. Further, the surface of the support may be subjected to an electrochemical treatment such as anodization, a blast treatment, a cutting treatment or the like.

As the material of the support, metal, resin, glass and the like are preferable.

Examples of the metal include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Above all, it is preferable that the support is made of aluminum using aluminum.

Further, the resin or glass may be imparted with conductivity by a treatment such as mixing or coating a conductive material.

<Conductive layer>
In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, it is possible to conceal scratches and irregularities on the surface of the support and control the reflection of light on the surface of the support.

The conductive layer preferably contains conductive particles and a resin.

Examples of the material of the conductive particles include metal oxides, metals, and carbon black.

Examples of the metal oxide include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of the metal include aluminum, nickel, iron, nichrome, copper, zinc, silver and the like.

Among these, it is preferable to use a metal oxide as the conductive particles, and it is more preferable to use titanium oxide, tin oxide, and zinc oxide.

When a metal oxide is used as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof.

Further, the conductive particles may have a laminated structure having core material particles and a coating layer covering the particles. Examples of the core material particles include titanium oxide, barium sulfate, zinc oxide and the like. Examples of the coating layer include metal oxides such as tin oxide.

When a metal oxide is used as the conductive particles, the volume average particle diameter thereof is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin.

Further, the conductive layer may further contain a hiding agent such as silicone oil, resin particles, and titanium oxide.

The average film thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

The conductive layer can be formed by preparing a coating liquid for a conductive layer containing each of the above-mentioned materials and a solvent, forming the coating film, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like. Examples of the dispersion method for dispersing the conductive particles in the coating liquid for the conductive layer include a method using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.

<Underlay layer>
In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing the undercoat layer, a charge injection blocking function can be imparted.

The undercoat layer preferably contains a resin. Further, an undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

Resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, and polyamide resin. , Polyamic acid resin, polyimide resin, polyamideimide resin, cellulose resin and the like.

The polymerizable functional group of the monomer having a polymerizable functional group includes an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group and a thiol group. Examples thereof include a carboxylic acid anhydride group and a carbon-carbon double bond group.

Further, the undercoat layer may further contain an electron transporting substance, a metal oxide, a metal, a conductive polymer and the like for the purpose of enhancing the electrical characteristics. Among these, it is preferable to use an electron transporting substance and a metal oxide.

Examples of the electron transporting substance include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halide compounds, silol compounds, and boron-containing compounds. .. An undercoat layer may be formed as a cured film by using an electron transporting substance having a polymerizable functional group as the electron transporting substance and copolymerizing it with the above-mentioned monomer having a polymerizable functional group.

Examples of the metal oxide include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide and the like. Examples of the metal include gold, silver and aluminum.

Further, the undercoat layer may further contain an additive.

The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

The undercoat layer can be formed by preparing a coating liquid for an undercoat layer containing each of the above-mentioned materials and solvents, forming this coating film, and drying and / or curing. Examples of the solvent used for the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

<Photosensitive layer>
The photosensitive layer of the electrophotographic photosensitive member is mainly classified into (1) a laminated photosensitive layer and (2) a single-layer photosensitive layer. (1) The laminated photosensitive layer has a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. (2) The single-layer type photosensitive layer has a photosensitive layer containing both a charge generating substance and a charge transporting substance.

(1) Laminated Photosensitive Layer The laminated photosensitive layer has a charge generation layer and a charge transport layer.

(1-1) Charge generating layer The charge generating layer preferably contains a charge generating substance and a resin.

Examples of the charge generating substance include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, phthalocyanine pigments and the like. Among these, azo pigments and phthalocyanine pigments are preferable. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferable.

The content of the charge generating substance in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, and more preferably 60% by mass or more and 80% by mass or less with respect to the total mass of the charge generating layer. preferable.

As the resin, polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin , Polyvinyl chloride resin and the like. Among these, polyvinyl butyral resin is more preferable.

Further, the charge generation layer may further contain additives such as an antioxidant and an ultraviolet absorber. Specific examples thereof include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

The average film thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

The charge generation layer can be formed by preparing a coating liquid for a charge generation layer containing each of the above-mentioned materials and a solvent, forming the coating film, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

(1-2) Charge Transport Layer The charge transport layer preferably contains a charge transport substance and a resin.

Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Be done. Among these, triarylamine compounds and benzidine compounds are preferable.

Further, the charge transporting substance may contain a plurality of types together. Hereinafter, specific examples of the charge transporting substance will be shown.

The content of the charge transporting substance in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less, based on the total mass of the charge transport layer. preferable.

Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin and the like. Among these, polycarbonate resin and polyester resin are preferable. As the polyester resin, a polyarylate resin is particularly preferable.

The content ratio (mass ratio) of the charge transporting substance and the resin is preferably 4: 10 to 20:10, more preferably 5: 10 to 12:10.

Further, the charge transport layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and an abrasion resistance improving agent. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. And so on.

The average film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

The charge transport layer can be formed by preparing a coating liquid for a charge transport layer containing each of the above-mentioned materials and a solvent, forming the coating film, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferable.

(2) Single-layer type photosensitive layer The single-layer type photosensitive layer is formed by preparing a coating liquid for a photosensitive layer containing a charge generating substance, a charge transporting substance, a resin and a solvent, forming this coating film, and drying the coating film. can do. The charge generating substance, the charge transporting substance, and the resin are the same as the examples of the materials in the above "(1) Laminated photosensitive layer".

<Protective layer>
In the present invention, a protective layer may be provided on the photosensitive layer. Durability can be improved by providing a protective layer.

The protective layer preferably contains conductive particles and / or a charge transporting substance and a resin.

Examples of the conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having a group derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferable.

Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, epoxy resin and the like. Of these, polycarbonate resin, polyester resin, and acrylic resin are preferable.

Further, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction at that time include a thermal polymerization reaction, a photopolymerization reaction, and a radiation polymerization reaction. Examples of the polymerizable functional group contained in the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. As the monomer having a polymerizable functional group, a material having a charge transporting ability may be used.

The protective layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slipper-imparting agent, and an abrasion resistance improver. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles. And so on.

The average film thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and preferably 1 μm or more and 7 μm or less.

The protective layer can be formed by preparing a coating liquid for a protective layer containing each of the above-mentioned materials and solvents, forming this coating film, and drying and / or curing. Examples of the solvent used for the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[Process cartridge, electrophotographic equipment]
The process cartridge of the present invention integrally supports the electrophotographic photosensitive member described above and at least one means selected from the group consisting of charging means, developing means, transfer means and cleaning means, and is an electrophotographic apparatus. It is characterized by being removable from the main body.

Further, the electrophotographic apparatus of the present invention is characterized by having the electrophotographic photosensitive member, charging means, exposure means, developing means and transfer means described above.

FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge 11 provided with an electrophotographic photosensitive member.

Reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven at a predetermined peripheral speed in the direction of an arrow about a shaft 2. The surface of the electrophotographic photosensitive member 1 is charged to a predetermined positive or negative potential by the charging means 3. Although the roller charging method using the roller type charging member is shown in the figure, a charging method such as a corona charging method, a proximity charging method, or an injection charging method may be adopted. The surface of the charged electrophotographic photosensitive member 1 is irradiated with exposure light 4 from an exposure means (not shown), and an electrostatic latent image corresponding to the target image information is formed. The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed with the toner contained in the developing means 5, and the toner image is formed on the surface of the electrophotographic photosensitive member 1. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred to the transfer material 7 by the transfer means 6. The transfer material 7 to which the toner image is transferred is conveyed to the fixing means 8, undergoes the toner image fixing process, and is printed out of the electrophotographic apparatus. The electrophotographic apparatus may have a cleaning means 9 for removing deposits such as toner remaining on the surface of the electrophotographic photosensitive member 1 after transfer. Further, a so-called cleanerless system may be used in which the above-mentioned deposits are removed by a developing means or the like without separately providing a cleaning means. The electrophotographic apparatus may have a static elimination mechanism for statically eliminating the surface of the electrophotographic photosensitive member 1 with preexposure light 10 from a preexposure means (not shown). Further, in order to attach / detach the process cartridge of the present invention to / from the main body of the electrophotographic apparatus, a guide means 12 such as a rail may be provided.

The electrophotographic photosensitive member of the present invention can be used in a laser beam printer, an LED printer, a copier, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the description of the following examples, the term "part" is based on mass unless otherwise specified.

<Manufacturing of electrophotographic photosensitive member>
An aluminum cylinder (JIS-A3003, aluminum alloy, length 257 mm) having a diameter of 24 mm was used as a support (conductive support).

Next, 214 parts of titanium oxide (TiO ₂ ) particles coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles, and 132 parts of phenol resin as a binder material (trade name: Pryofen J-325, DIC, resin solid content: 60% by mass), 98 parts of 1-methoxy-2-propanol as a solvent was placed in a sand mill using 450 parts of glass beads with a diameter of 0.8 mm, rotation speed: 2000 rpm, dispersion treatment time: A dispersion treatment was carried out under the conditions of a set temperature of cooling water of 18 ° C. for 4.5 hours to obtain a dispersion liquid.

At this time, after removing the glass beads with a mesh (opening: 150 μm), filtration was performed using a filter having a pore diameter of 5 um to obtain a dispersion liquid.

Further, silicone resin particles (trade name: Tospearl 120, manufactured by Momentive Performance Materials Japan LLC, average particle size 2 μm) were added to the dispersion liquid as a surface roughness imparting material. The amount of the silicone resin particles added at this time was set to be 10% by mass with respect to the total mass of the metal oxide particles and the binder material in the dispersion liquid after removing the glass beads. Further, silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning) as a leveling agent is dispersed so as to be 0.01% by mass with respect to the total mass of the metal oxide particles and the binder material in the dispersion liquid. A coating liquid for a conductive layer was prepared by adding to the liquid and stirring.

The coating liquid for the conductive layer was immersed and coated on the support, and the obtained coating film was dried at 150 ° C. for 30 minutes and thermoset to form a conductive layer having a film thickness of 30 μm.

Next, N-methoxymethylated 6-nylon resin: 15 parts of Tredin EF-30T (manufactured by Nagase ChemteX) and copolymerized nylon resin: 5 parts of Amylan CM8000 (manufactured by Toray) in 220 parts of methanol and 110 parts of 1-butanol. A coating solution for the undercoat layer was prepared by dissolving in a mixed solvent.

At this time, a 1 um filter (trade name: U-Tech, manufactured by Asahi Kasei) was used for the circulation machine for the undercoat layer.

The coating liquid for the undercoat layer is immersed and coated on the conductive layer to form a coating film, and the obtained coating film is dried at a temperature of 100 ° C. for 10 minutes to form an undercoat layer having a film thickness of 0.65 μm. did.

Next, the Bragg angles (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction were 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and A crystalline hydroxygallium phthalocyanine crystal (charge generator) having a peak at 28.3 ° was prepared. 10 parts of this hydroxygallium phthalocyanine crystal, 0.1 part of the compound represented by the structural formula (A), 5 parts of polyvinyl butyral (trade name: Eslek BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone in diameter. It was placed in a sand mill using 0.8 mm glass beads and dispersed for 1.5 hours. Next, 250 parts of ethyl acetate was added thereto to prepare a coating liquid for a charge generation layer.

This coating liquid for the charge generating layer is immersed and coated on the undercoat layer to form a coating film, and the obtained coating film is dried at 100 ° C. for 10 minutes to form a charge generating layer having a film thickness of 0.15 μm. Was formed.

(Example 1)
Next, four parts each of the compound represented by the structural formula (CTM-1) and the compound represented by the structural formula (CTM-2), and bisphenol Z type polycarbonate (trade name: PCZ-400, Mitsubishi Gas Chemical Company) A coating liquid for a charge transport layer was prepared by dissolving 10 parts (manufactured by Co., Ltd.) in a mixed solvent of 40 parts of dimethoxymethane and 60 parts of chlorobenzene.

At this time, filtration was performed using a rotary ceramic filter (trade name: Dynafilter, manufactured by Koki Holdings Co., Ltd.) having a pore diameter (average pore diameter) of a ceramic (Al2O3) film of 500 nm.

The coating liquid for the charge transport layer was immersed and coated on the charge generation layer, and the obtained coating film was dried at 120 ° C. for 35 minutes to form a charge transport layer having a film thickness of 18 μm.

In this way, an electrophotographic photosensitive member having a support, a conductive layer, an undercoat layer, a charge generation layer, and a charge transport layer in this order was produced.

(Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the structural formula (CTM-1) was changed to the structural formula (CTM-4).

(Example 3)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the structural formula (CTM-2) was changed to the structural formula (CTM-3).

(Example 4)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the 500 nm rotary ceramic filter was changed to a centrifuge (trade name: CHB209, manufactured by Alfa Laval).

Centrifugation conditions are as follows: rotation speed 6000 rpm, flow rate 200 L / H
(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the rotary ceramic filter was not used in Example 1.

[Evaluation]
As an evaluation device, a laser printer manufactured by Hewlett-Packard Co., Ltd. (Color LaserJet Enterpress M552 modified machine) was used. The manufactured electrophotographic photosensitive member was attached to the process cartridge for black color, the process cartridge was attached to the station of the black process cartridge, and an image was output.

The evaluation was performed in an environment of a temperature of 30 ° C. and a humidity of 80% RH. First, on A4 size plain paper, one solid white image and one solid black image were continuously output in this order, and then 5000 sheets of paper passing test (printing rate 1%) were performed and solid. Image output was continuously performed in the order of one white image and one solid black image.

The evaluation confirmed the presence or absence of white spots and black spots, and the results are shown in Table 1.

1 Electrophotographic photosensitive member 2 axes 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means

Claims (6)

A method for manufacturing an electrophotographic photosensitive member in which a charge transport layer is provided by applying a coating liquid on a support and drying the support.
A method for producing an electrophotographic photosensitive member, which comprises a step of removing foreign substances having a particle size of 5 nm or more from the coating liquid by a rotating ceramic filter or a centrifuge. The coating is to immerse the support in the coating liquid of the immersion coating device and pull it up.
The production of the electrophotographic photosensitive member according to claim 1, wherein the coating liquid is circulated between the dipping coating device and the rotating ceramic filter or the centrifuge connected to the dipping coating device. Method. The method for producing an electrophotographic photosensitive member according to claim 1 or 2, wherein the viscosity of the coating liquid is 30 mPa · s or more and 500 mPa · s or less. An electrophotographic photosensitive member produced by the method according to any one of claims 1 to 3. The electrophotographic photosensitive member according to claim 4 and at least one means selected from the group consisting of charging means, developing means, transfer means and cleaning means are integrally supported and detachable from the main body of the electrophotographic apparatus. A process cartridge characterized by that. An electrophotographic apparatus comprising the electrophotographic photosensitive member, charging means, exposure means, developing means and transfer means according to claim 4.

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