JP2005070772A - Method for manufacturing coating liquid for formation of photosensitive layer, electrophotographic photoreceptor using coating liquid, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a coating liquid for formation of a photosensitive layer of an electrophotographic photoreceptor, the liquid having high dispersibility, capable of keeping the dispersed state for a long period, having excellent coating property and inducing no defect in a coating film, to provide an electrophotographic photoreceptor which is produced by using the above coating liquid for formation of a photosensitive layer of an electrophotographic photoreceptor and which produces an image of high picture quality without a defect, to provide an image forming apparatus using the above electrophotographic photoreceptor, and further, to provide a process cartridge using the above electrophotographic photoreceptor. <P>SOLUTION: The method for manufacturing a coating liquid comprising at least a solvent and fine particles for formation of a photosensitive layer of an electrophotographic photoreceptor includes the steps of: incorporating a dispersion medium into the coating liquid for dispersion treatment so as to disperse the fine particles in the solvent into ≤10 μm volume average particle size, and then irradiating the dispersion liquid with ultrasonic waves. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member, which has good dispersibility, can maintain a dispersed state for a long period of time, has excellent coatability, and coating. Method for producing the coating solution in which film defects do not occur, electrophotographic photosensitive member that does not generate an abnormal image using the coating solution for forming a photosensitive layer of the electrophotographic photosensitive member of the present invention, an image forming apparatus, and the image formation The present invention relates to an apparatus process cartridge.

In an image forming apparatus such as a copying machine, a printer, and a facsimile machine using an electrophotographic method, a uniformly charged photoconductor is irradiated with writing light modulated by image data, and the photoconductor is statically applied to the photoconductor. An electrostatic latent image is formed, toner is supplied to the photosensitive member on which the electrostatic latent image is formed by a developing unit, and a toner image is formed on the photosensitive member and developed. The image forming apparatus transfers the toner image on the photoconductor to the transfer paper (recording paper) by the transfer unit, and then fixes the toner transferred on the transfer paper by the fixing unit by heating and pressurizing, and remains on the surface of the photoconductor. The collected toner is collected by a method such as scraping with a cleaning blade at the cleaning unit.
In an image forming apparatus using such an electrophotographic method, it has been known that, by reducing the coefficient of friction on the surface of the photoreceptor, unnecessary toner adhesion can be prevented and an image free of background stains can be obtained. It has been. In addition, a photoreceptor having a small surface friction coefficient can reduce the amount of surface wear and extend the life of the photoreceptor.
In other words, the reason for determining the life of the photoconductor is the wear of the photoconductive layer of the photoconductor. When a certain amount of the photoconductive layer is scraped off, the electrical characteristics of the photoconductor change and an appropriate image forming process can be performed. Disappear. This friction is generated in all the parts where the photoconductor and other image forming units such as the developing unit and the transfer unit are in contact with each other in the image forming process described above. It is possible to reduce the wear generated at the site and improve the life of the photoreceptor.
Furthermore, it is known that by reducing the coefficient of friction on the surface of the photoconductor, the transfer rate when the toner image formed on the photoconductor is transferred to the transfer target is improved. That is, since it is possible to suppress worm-eating prints and to reduce the amount of residual toner after transfer, there are also effects such as a reduction in the amount of waste toner.

As a method for reducing the coefficient of friction on the surface of the photoreceptor, an image forming apparatus having a mechanism for supplying a lubricant to the surface of the photoreceptor has been proposed and put to practical use, as proposed in Patent Document 1. It has become. However, since such a mechanism is provided around the photosensitive member, an increase in size and complexity of the apparatus cannot be avoided, and problems such as an increase in cost and deterioration in maintainability occur. Further, as a different method for reducing the coefficient of friction of the photoreceptor, it has been proposed to add a lubricant that reduces the friction coefficient to the surface layer of the photoreceptor.
For example, as the lubricant, a fluorine atom-containing resin such as polytetrafluoroethylene, a spherical acrylic resin, a polyethylene resin powder, or a metal oxide powder such as silicon oxide or aluminum oxide is known. In particular, a fluorine atom-containing resin containing a large amount of fluorine atoms has a great effect as a lubricant since the surface energy is extremely small. Such a fluorine atom-containing resin is used as crystalline fine particles, and after being dispersed in a binder resin such as an acrylic resin, a polyester resin, a polyurethane resin, or a polycarbonate resin, it is formed as a surface layer or a protective layer of the photoreceptor. Be filmed.

  However, the fluorine atom-containing resin fine particles are likely to have problems in dispersibility and agglomeration. As a method for dispersing the fluorine atom-containing resin fine particles, a high-speed liquid collision dispersion or a dispersion method using a dispersion medium is used. As an example, in Patent Documents 2 and 3, the use of a high-pressure liquid collision dispersion device in a method for producing a coating solution for forming a photosensitive layer of an electrophotographic photoreceptor to which fluorine atom-containing resin tetrafluoroethylene fine particles are added is disclosed in Patent Documents. 4 uses a sand mill with 1 mm glass beads after a high-pressure liquid collision dispersion device in a method for producing a photosensitive layer forming coating solution to which fluorine atom-containing resin tetrafluoroethylene fine particles are added. It is disclosed that a sand mill is used to disperse the fluorine atom-containing resin contained in the outermost layer of the photoreceptor. Certainly, these methods can disperse fine particles under specific conditions. For example, when specific fluorine atom-containing resin fine particles such as PFA are used, or a large amount of fluorine atom-containing resin fine particles are used in the photosensitive layer forming coating solution. In certain examples, such as when it is contained in the case, the disclosed technique may not be effective enough. For this reason, the coating solution for forming the photosensitive layer may not be maintained in a dispersed state for a long period of time, and it is difficult to produce a smooth film from such a coating solution. It had image defects such as image unevenness and pinholes. In addition, it has been unavoidable that problems such as nozzle clogging occur during spray coating.

JP 56-142567 A Japanese Patent Laid-Open No. 06-332219 JP 2000-121212 A Japanese Patent Laid-Open No. 08-184980 Japanese Patent No. 0267778

The object of the present invention is to solve the above-mentioned conventional problems. Therefore, in view of the above-mentioned conventional technology, the object of the present invention is an electron that has good dispersibility, can maintain a dispersed state for a long period of time, has excellent coatability, and does not cause coating film defects. The object is to provide a method for producing a coating solution for forming a photosensitive layer of a photographic photoreceptor.
It is a further object of the present invention to provide an electrophotographic photosensitive member that gives a high-quality image free from defects produced using the coating solution for forming a photosensitive layer of the electrophotographic photosensitive member.
Another object of the present invention is to provide an image forming apparatus using the electrophotographic photosensitive member.
A further object of the present invention is to provide a process cartridge using the electrophotographic photosensitive member.

  The above-mentioned problem is (1) “a method for producing a coating solution for forming a photosensitive layer of an electrophotographic photoreceptor comprising at least a solvent and fine particles” according to the present invention. And then, after dispersing the volume average particle size of the fine particles in the solvent to 10 μm or less, the dispersion is irradiated with ultrasonic waves, and a method for producing a photosensitive layer forming coating solution for an electrophotographic photosensitive member (2) “Manufacturing of a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to item (1), wherein the coating solution is used for forming the outermost layer of the electrophotographic photosensitive member.” Method ", (3)" Item (1) or (2), wherein the fine particles are composed of at least one kind of fine particles and are composed of one or more kinds of fluorine atom-containing resin fine particles " Production of a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to the item (4) "The electrophotographic photosensitive member according to any one of items (1) to (3), wherein the dispersion medium is a zirconia ball having a diameter of not less than 0.3 mm and not more than 5 mm. (5) “When dispersing the volume average particle diameter of the fine particles in the solvent to 10 μm or less using the dispersion medium, at least the dispersion medium, the solvent, Any one of the items (1) to (4) is characterized in that a dispersion treatment is performed by applying high-speed vibration at a frequency of 100 to 2000 times to the container containing the fine particles. (1) to (6) above, wherein the ultrasonic wave applied to the dispersion liquid has a frequency of 15 kHz to 60 kHz. As described in any of paragraph (5) Method for producing photosensitive layer forming coating solution for electrophotographic photosensitive member ”, (7)“ The coating solution contains a binder resin, and the volume average particle size of the fine particles in the solvent is dispersed to 10 μm or less. Thereafter, the binder resin is added, and thereafter, ultrasonic waves are applied, and the coating for forming a photosensitive layer of the electrophotographic photosensitive member according to any one of (1) to (6) above (8) "The coating liquid is a coating liquid having a solid content concentration at the time of dispersing fine particles and a solid content concentration at the time of coating, and is diluted to a solid content concentration at the time of coating. And then, ultrasonic waves are irradiated, and this is achieved by the method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to any one of (1) to (7) above. Is done.

  In addition, the above-mentioned problem is solved by (9) “Electrophotographic photosensitive member having one or more photosensitive layers on a conductive support, wherein at least one photosensitive layer is the above-mentioned items (1) to (1). It is achieved by an electrophotographic photoreceptor characterized in that it is formed using a photosensitive layer forming coating solution produced by the production method according to any one of items 8).

  The above-described problem is solved by (10) of the present invention, in an image forming apparatus having at least an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit. And an image forming apparatus characterized in that the electrophotographic photosensitive member is described.

  Still further, the above-described problem is addressed in (11) of the present invention, which comprises at least one of charging means, exposure means, developing means, transfer means, and cleaning means, and the electrophotographic photosensitive member. This is achieved by the “process cartridge for an image forming apparatus” described.

  Furthermore, the above-mentioned problem is produced by the production method according to any one of (12) “(1) to (8)” of the present invention. This is achieved by the “forming coating solution”.

As a result of intensive studies on the above problems, the present inventors have made a method for producing a coating solution for forming a photosensitive layer, which comprises at least a solvent and one or more kinds of fluorine atom-containing resin fine particles and forms the outermost layer of the electrophotographic photosensitive member. In the above, the dispersion liquid is further added to the coating liquid to perform a dispersion treatment, and after dispersing the volume average particle diameter of the fine particles in the solvent to 10 μm or less, the dispersion liquid is irradiated with ultrasonic waves. The present inventors have found that the problem can be solved and have reached the present invention.
Here, the photosensitive layer in this specification is not only a photosensitive layer in a narrow sense, but also charge generation in the case of a subbing layer, a photosensitive layer, a protective layer, and a function-separated type photosensitive member on a support. It also means a layer provided on a support of an electrophotographic photosensitive member such as a layer, a charge transport layer, and an intermediate layer.
A coating solution for forming a photosensitive layer of an electrophotographic photosensitive member produced by such a manufacturing method has good dispersibility, can maintain a dispersed state for a long period of time, and has excellent coatability. No coating film defects occurred.
The reason for this is not clear, but the coating solution for forming a photosensitive layer prepared by dispersing fluorine atom-containing resin fine particles in a solvent using a dispersion medium is not sufficiently refined and dispersed. It has been found that the dispersed state may not be maintained for a long time due to insufficientness. However, by applying a dispersion treatment that applies shear stress with the dispersion media, and then irradiating the dispersion with ultrasound, the fluorine atom-containing resin particles that were not sufficiently refined by the dispersion treatment with the dispersion media were refined by ultrasound. In order to maintain the micronized state, it is presumed that the dispersed state can be maintained for a long time. A ball mill, an attritor, a sand mill, a rade devil, a vibration mill, a planetary ball mill, or the like can be used for dispersion.

  Further, according to the present invention, the dispersion medium has a good dispersibility and a dispersed state by producing a coating solution for forming a photosensitive layer using a zirconia ball having a diameter of φ0.3 mm or more and φ5 mm or less. It is possible to provide a method for producing a coating solution for forming a photosensitive layer that is capable of holding a film for a long period of time, has excellent coating properties, and does not cause defects in the coating film.

  Further, according to the present invention, the volume of fluorine atom-containing resin fine particles in the solvent is obtained by applying high-speed vibration at a frequency of 100 to 2000 times per minute in the container together with the mixture of the solvent and the fine particles. After dispersing the average particle size to 10 μm or less, the dispersion is irradiated with ultrasonic waves having a frequency of 15 kHz or 60 kHz to produce a coating solution for forming a photosensitive layer. It is possible to provide a method for producing a coating solution for forming a photosensitive layer that is capable of holding a film for a long period of time, has excellent coating properties, and does not cause defects in the coating film.

  According to the invention, the photosensitive layer forming coating solution contains a binder resin, and after the fine particles are dispersed in the coating solution to a volume average particle size of 10 μm or less, the binder resin is added to the coating solution. Further, by irradiating the dispersion with ultrasonic waves to prepare a coating solution for forming a photosensitive layer, the dispersion has better dispersibility and can maintain the dispersed state for a longer period of time. A method for producing a layer-forming coating solution is provided.

  Further, according to the present invention, the photosensitive layer forming coating solution is a coating solution in which the solid content concentration at the time of fine particle dispersion differs from the solid content concentration at the time of coating, and is diluted to the solid content concentration at the time of coating. Then, by irradiating with ultrasonic waves, a method for producing a coating solution for forming a photosensitive layer, which has better dispersibility and can maintain the dispersed state for a longer period of time, is provided.

  According to the present invention, in the electrophotographic photosensitive member having one or more photosensitive layers on the conductive support, at least one photosensitive layer is a coating for forming a photosensitive layer of the electrophotographic photosensitive member of the present invention. An electrophotographic photosensitive member that provides a high-quality image without defects by being formed using a working solution is provided.

  According to the present invention, in an image forming apparatus having at least an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit, by using the electrophotographic photosensitive member of the present invention, high image quality without defects can be obtained. An image forming apparatus that provides an image is provided.

  The present invention also provides a process cartridge for an image forming apparatus comprising at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit and the electrophotographic photosensitive member of the present invention. . As a result, the electrophotographic photosensitive member that gives a high-quality image free from defects and other process members can be easily replaced in a short time, so that the time required for maintenance can be shortened and the cost can be reduced. At the same time, since the process member and the electrophotographic photosensitive member are integrated, advantages such as improvement in the accuracy of the mounting position can be obtained.

  The present invention relates to a method for producing a coating solution for forming an outermost photosensitive layer of an electrophotographic photoreceptor, comprising at least a solvent and one or more kinds of fluorine atom-containing resin fine particles, and the coating solution further comprises φ0.3 mm or more. Dispersion treatment is performed by adding a dispersion medium composed of zirconia balls of φ5 mm or less and applying high-speed vibration at a frequency of 100 to 2000 times per minute, so that the volume average particle size of the fine particles in the solvent is 10 μm or less. After dispersion, the dispersion is irradiated with ultrasonic waves having a frequency of 15 kHz or more and 60 kHz or less, so that the dispersibility is good and the dispersed state can be maintained for a long time. The coating solution for forming a protective layer that contributes to the reduction of production costs can be suppressed because it has excellent coating properties and no coating film defects. It is subjected. Furthermore, an electrophotographic photosensitive member that provides a high-quality image free of image defects produced using the protective layer-forming coating solution, an image forming apparatus using the same, and a process cartridge for the image forming apparatus are provided. It has an excellent effect.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member of the present invention, showing an electrophotographic photosensitive member having a structure in which a photosensitive layer is provided on a conductive substrate. 2, 3 and 4 each show a configuration example of another electrophotographic photosensitive member according to the present invention. FIG. 2 shows a function-separated type electrophotographic photoreceptor in which the photosensitive layer is composed of a charge generation layer (CGL) and a charge transport layer (CTL), and FIG. 3 shows a conductive substrate and a function-separated type photoconductor. 2 shows an electrophotographic photosensitive member in which an undercoat layer is inserted between the layers CGL and CTL. FIG. 4 shows an electrophotographic photosensitive member in which a protective layer is further formed on the photosensitive layer of the type shown in FIG. The electrophotographic photosensitive member according to the present invention may have other layers other than the above as long as it has at least a photosensitive layer on a conductive support, and the type of the photosensitive layer. May be combined arbitrarily.

The conductive support used in the electrophotographic photosensitive member in the present invention includes a conductor or an insulator subjected to a conductive treatment, for example, a metal such as Al, Ni, Fe, Cu, Au, or an alloy thereof, polyester A thin film made of a metal such as Al, Ag, Au or a conductive material such as In ₂ O ₃ or SnO ₂ on an insulating substrate such as polycarbonate, polyimide or glass, carbon black, graphite, aluminum, A resin substrate in which metal powder such as copper or nickel, conductive glass powder or the like is uniformly dispersed to impart conductivity to the resin, paper subjected to conductive treatment, or the like can be used. The shape of the conductive support is not particularly limited, and any of a plate shape, a drum shape, and a belt shape can be used. However, when a belt-like support is used, it is necessary to provide a driving roller and a driven roller inside. While the equipment becomes complicated and large, there are advantages such as increased flexibility in layout. However, when forming a protective layer, there is a possibility that cracks called cracks may occur on the surface due to insufficient flexibility of the protective layer, which may cause granular background stains. It is done. For this reason, a drum-like member having high rigidity is preferably used as the support.

  If necessary, an undercoat layer may be provided between the conductive support and the photosensitive layer. Such an undercoat layer is provided for the purpose of improving adhesiveness, preventing moire, improving the coatability of the upper layer, and reducing residual potential. The undercoat layer generally comprises a resin as a main component, but these resins are resins having a high solubility resistance to general organic solvents in consideration of applying a photosensitive layer thereon using a solvent. It is desirable that Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resins, alkyd-melamine resins, and epoxy resins. Examples thereof include curable resins that form a three-dimensional network structure. Further, fine powders such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like, or metal sulfides and metal nitrides may be added. These undercoat layers can be formed by a common coating method using an appropriate solvent.

Further, as the undercoat layer, a metal oxide layer formed by using, for example, a sol-gel method using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like is also useful.
In addition, as the undercoat layer, an anodized layer of Al ₂ O ₃ , an organic material such as polyparaxylylene (parylene), or an inorganic material such as SnO ₂ , TiO ₂ , ITO, or CeO ₂ is used. It may be provided by a vacuum thin film manufacturing method.
The thickness of the undercoat layer is suitably about 0.1 to 5 μm.

  As the kind of the photosensitive layer used in the electrophotographic photosensitive member of the present invention, any of Se type, OPC type and the like can be applied. Examples of inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, and selenium-arsenic compounds. In particular, environmentally friendly and inexpensive OPC is good. Of these, the OPC system will be briefly described below.

  The photosensitive layer in the present invention may be either a single layer type or a laminated type, but here, a laminated type will be described. First, the charge generation layer will be described.

The charge generation layer is a layer mainly composed of a charge generation material, and a binder resin may be used as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Examples of inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, and selenium-arsenic compounds.
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Goido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Polyacrylamide or the like is used. These binder resins can be used alone or as a mixture of two or more.
Moreover, you may add a charge transport substance as needed. In addition to the binder resin described above, a polymer charge transporting material is also preferably used as the binder resin for the charge generation layer.

As a method for forming the charge generation layer, a vacuum thin film preparation method and a casting method from a solution dispersion system can be largely mentioned.
Examples of the former method include a glow discharge polymerization method, a vacuum deposition method, a CVD method, a sputtering method, a reactive sputtering method, an ion plating method, and an accelerated ion injection method. This vacuum thin film manufacturing method can satisfactorily form the inorganic material or organic material described above.
In addition, in order to provide the charge generation layer by the latter casting method, a ball mill using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone together with a binder resin, if necessary, the inorganic or organic charge generation material described above, It can be formed by dispersing with an attritor, sand mill or the like, and applying the solution after diluting the dispersion appropriately. The application can be performed using a commonly used method such as a dip coating method, spray coating, or bead coating.

  The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

The charge transport layer is a layer intended to hold a charged charge and to couple the charge generated and separated in the charge generation layer by exposure to the charged charge that has been held. In order to achieve the purpose of holding the charged charge, it is required that the electric resistance is high. Further, in order to achieve the purpose of obtaining a high surface potential with the charged charge that has been held, it is required that the dielectric constant is small and the charge mobility is good.
The charge transport layer for satisfying these requirements is composed of a charge transport material and a binder resin used as necessary. Such a charge transport layer can be formed by dissolving or dispersing these charge transport materials and a binder resin in an appropriate solvent, and applying and drying them. If necessary, an appropriate amount of additives such as a plasticizer, an antioxidant, and a leveling agent can be added to the charge transport layer in addition to the charge transport material and the binder resin.

Examples of the charge transport material include a hole transport material and an electron transport material.
Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4-one, 1,3,7-tri Examples thereof include electron accepting substances such as nitrodibenzothiophene-5,5-dioxide. These electron transport materials can be used alone or as a mixture of two or more.
Examples of the hole transporting material include the electron donating materials shown below and are used favorably. For example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline , Phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These hole transport materials can be used alone or as a mixture of two or more.
Further, the polymer charge transporting material may have the following structure.

(A) Polymer having carbazole ring For example, poly-N-vinylcarbazole, JP-A-50-82056, JP-A-54-9632, JP-A-54-11737, JP-A-4-175337 And the compounds described in JP-A-4-183719 and JP-A-6-234841.
(B) Polymer having a hydrazone structure For example, JP-A-57-78402, JP-A-61-20953, JP-A-61-296358, JP-A-1-134456, JP-A-1-134456 179164, JP-A-3-180851, JP-A-3-180852, JP-A-3-50555, JP-A-5-310904, JP-A-6-234840, and the like. Is done.
(C) Polysilylene polymer For example, JP-A-63-285552, JP-A-1-88461, JP-A-4-264130, JP-A-4-264131, JP-A-4-264132, Examples thereof include compounds described in Kaihei 4-264133 and JP-A-4-289867.
(D) Polymer having a triarylamine structure For example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-134457, JP-A-2-282264, JP-A-2- Examples include compounds described in JP-A-304456, JP-A-4-133605, JP-A-4-133066, JP-A-5-40350, and JP-A-5-202135.
(E) Other polymers For example, formaldehyde condensation polymer of nitropyrene, JP-A-51-73888, JP-A-56-150749, JP-A-6-234836, JP-A-6-234837 The described compounds and the like are exemplified.

  The polymer having an electron donating group used in the present invention is not limited to the above-mentioned polymer, but also a copolymer of a known monomer, a block polymer, a graft polymer, a star polymer, It is also possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A-3-109406.

  Further, examples of polycarbonates, polyurethanes, polyesters, and polyethers having a triarylamine structure that are further useful as the polymer charge transporting material used in the present invention include, for example, JP-A 64-1728 and JP-A 64- No. 13061, JP-A 64-19049, JP-A-4-11627, JP-A-4-225014, JP-A-4-230767, JP-A-4-320420, JP-A-5-232727 No. 7, JP-A-7-56374, JP-A-9-127713, JP-A-9-222740, JP-A-9-265197, JP-A-9-211877, JP-A-9-304956. And the like.

Furthermore, as a binder resin that can be used in combination with the charge transport layer, for example, polycarbonate, polyester, methacrylic resin, acrylic resin, polyethylene, vinyl chloride, vinyl acetate, polystyrene, phenol resin, epoxy resin, polyurethane, polyvinylidene chloride, alkyd resin, Silicone resin, polyvinyl carbazole, polyvinyl butyral, polyvinyl formal, polyacrylate, polyacrylamide, phenoxy resin, and the like are used. These binder resins can be used alone or as a mixture of two or more.
The film thickness of the charge transport layer is suitably about 5 to 100 μm. However, due to the recent demand for higher image quality, it has been attempted to make the charge transport layer thinner and achieve higher image quality of 1200 dpi or more. For this purpose, a thickness of about 5 to 30 μm is more preferable.

Additives such as other antioxidants and plasticizers used for rubbers, plastics, fats and the like may be added to the charge transport layer in the present invention.
Furthermore, a leveling agent may be added in the charge transport layer. Examples of such leveling agents include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain, and the amount used is 100 parts by weight of binder resin. From 0 to 1 part by weight is appropriate.
As the coating method, a commonly used method such as a dip coating method, spray coating, or bead coating method can be used.

  Further, when the charge transport layer is the outermost layer of the photoreceptor and the coating liquid for forming the charge transport layer is composed of at least a solvent and one or more kinds of fluorine atom-containing resin fine particles, as shown in the present invention. The dispersion medium is contained in the coating liquid and vibrated at high speed to disperse the volume average particle size of the fine particles in the solvent to 10 μm or less. Since it is possible to maintain the dispersed state for a long time, the quality is stable, the service life is long, the coating property is excellent, and the occurrence of defective products can be suppressed because there are no defects in the coating film. Thus, it is possible to provide a coating liquid for forming a charge transport layer of an electrophotographic photosensitive member that contributes to a reduction in production cost.

  As the material of the dispersion medium that can be used in the present invention, it is preferable to use zirconia balls because impurities may be mixed in the coating liquid due to wear of the medium. The diameter of the dispersion medium is preferably φ0.3 mm or more and φ5 mm or less. When media with a diameter of less than 0.3 mm is used, the productivity when separating from the dispersion after dispersion is greatly reduced. When a medium exceeding φ5 mm is used, the dispersion force is reduced, and fine dispersion may not be performed. Thus, it is possible to provide a coating liquid having better dispersibility within the above range. When the dispersion medium is contained in the coating liquid and vibrated at high speed, the applied frequency is 100 times or more and 2000 times or less per minute, and A: in the longitudinal direction with respect to the container containing the coating liquid Preferably, the vibration is performed by any one of vibration, B: vibration in the horizontal direction, C: vibration combined with the vertical direction and horizontal direction, D: vibration that draws a circle, and A to D. By vibrating by such means, the effect of the present invention becomes more remarkable, and it becomes possible to provide a coating liquid having better dispersibility.

  In the present invention, when preparing the coating liquid for forming the charge transport layer, the frequency of the ultrasonic wave applied to the dispersion is preferably 10 kHz or more and 100 kHz or less in order to disperse the fine particles. When the frequency is lower than 10 kHz, the cavitation strength is weakened, the dispersion ability is lowered, and the ultrasonic effect may not be sufficiently obtained. On the other hand, when the frequency is higher than 100 kHz, the coagulation effect is strongly expressed, so that a sufficient dispersion effect may not be obtained. Furthermore, a preferable frequency range is 15 kHz or more and 60 kHz. In this range, the dispersion effect due to the ultrasonic wave is exhibited, and the aggregating action is not strongly expressed. The ultrasonic irradiation time is preferably 1 minute or longer, and generally 60 minutes or shorter, although it depends on the composition of the dispersion. If it is 1 minute or less, it is not preferable that the effect of the present invention is not observed, but if it is 60 minutes or more, adverse effects such as a decrease in the molecular weight of the binder resin contained in the coating liquid may occur.

  In the present invention, the coating liquid for forming a charge transport layer contains a binder resin, but dispersion by a dispersion medium has an adverse effect such as lowering the molecular weight of the binder resin due to the dispersion force, so It is preferable that the binder resin is not contained at the time when the volume average particle size is dispersed to 10 μm or less in the solvent by liquid collision dispersion. In addition, if the binder resin is added after irradiating the dispersion with ultrasonic waves to produce the charge transport layer forming coating solution, the dispersion state may be adversely affected. It is preferable to add.

  In the present invention, the photosensitive layer forming coating solution is a coating solution in which the solid content concentration at the time of fine particle dispersion differs from the solid content concentration at the time of coating, and after being diluted to the solid content concentration at the time of coating, Is preferably irradiated. If the coating liquid is diluted after being irradiated with ultrasonic waves, the dispersed coating liquid is impacted, so that it may be impossible to maintain the dispersed state for a long period of time.

In addition, when the charge transport layer is the outermost layer, the photoreceptor of the present invention may contain a filler as fine particles in the charge transport layer.
Filler materials include organic filler materials and inorganic filler materials. Examples of the organic filler material include fluorine atom-containing resin fine powder such as polytetrafluoroethylene, silicone resin powder, and a-carbon powder. Examples of the inorganic filler material include copper, tin, aluminum, and indium. Metal powder, silica, tin oxide, zinc oxide, titanium oxide, alumina, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony-doped tin oxide, tin-doped indium oxide and other metal oxides, tin fluoride Metal fluorides such as calcium fluoride and aluminum fluoride, and inorganic materials such as potassium titanate and boron nitride.

Since the filler made of an inorganic pigment has a higher hardness than the filler made of an organic material, the wear resistance of the outermost layer of the photoreceptor can be further improved. However, generally, when the wear resistance of the latent image carrier is improved, the surface portion of the latent image carrier is hardly worn, but the surface portion is caused by reactive gases such as ozone and NOx generated during charging. It is known that the resistance is lowered, the electrostatic charge on the surface portion is gradually not retained, and the electrostatic charge moves toward the surface. As a result, the electrostatic latent image is blurred and an abnormal image called image blur or image flow that occurs when the electrostatic latent image is developed with toner or the like occurs. Therefore, the filler used in the present invention preferably has a high resistance of 10 ¹⁰ Ωcm or more. By using such a filler, it is possible to suppress the resistance of the outermost layer of the latent image carrier from being lowered, and to significantly suppress the occurrence of the abnormal image.

Among these fillers, silica, titanium oxide, and alumina can be used effectively. Further, since these filler materials are cheaper and easier to obtain than other metal oxide fine particles, it is possible to reduce the manufacturing cost of the latent image carrier.
Among these, α-type alumina, which has a hexagonal close-packed structure with high insulation, high thermal stability, and high wear resistance, is particularly useful in terms of suppressing image blur and improving wear resistance. . Such filler materials may be used alone or in admixture of two or more.
These filler materials can be dispersed by using an appropriate disperser together with a charge transport substance, a binder resin, a solvent, etc., but by using the dispersion method shown in the present invention, a filler-containing charge transport layer having good dispersibility can be formed. The coating liquid can be produced. The average primary particle size of the filler is 0.05 to 1.0 μm, preferably 0.1 to 0.3 μm.
If the average primary particle size of the filler is too smaller than 0.05 μm, the wear resistance may be insufficient. On the other hand, if the average primary particle diameter of the filler is too larger than 1.0 μm, the optical writing light applied to the latent image carrier is scattered by the filler, resulting in a decrease in transmittance, resulting in image blurring and character thickening. Sometimes.

  The filler concentration in the surface layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoreceptor, but is preferably 5 to 60% by weight. In addition, these fillers can be contained in the entire charge transport layer, but since the exposed area potential may be high, the outermost surface side of the charge transport layer has the highest filler content, and the conductive support It is preferable that the filler concentration is gradually increased from the conductive support side to the surface side, for example, by providing a filler concentration gradient so that the body side is lowered, or by forming a plurality of charge transport layers.

Next, the case where the photosensitive layer has a single layer structure will be described.
When a single-layer photosensitive layer is provided by a casting method, in many cases, such a single-layer photosensitive layer is obtained by dissolving or dispersing a charge generating substance, a low molecular weight molecule, and a polymer charge transporting substance in an appropriate solvent, and applying and drying the solution. Can be formed. As the charge generating substance and the charge transporting substance, the materials described above can be used.
In addition, a plasticizer can be added to the single-layer photosensitive layer as necessary. Furthermore, as the binder resin that can be used as necessary, the binder resins mentioned above for the charge transport layer can be used as they are. In addition, the binder resin mentioned in the charge generation layer may be mixed and used.

Further, when the single-layer photosensitive layer is the outermost layer of the photoreceptor and the single-layer photosensitive layer forming coating solution is composed of at least a solvent and one or more kinds of fluorine atom-containing resin fine particles, it is shown in the present invention. As described above, the dispersion medium is contained in the coating solution and vibrated at a high speed so that the volume average particle diameter of the fine particles in the solvent is dispersed to 10 μm or less, and then the dispersibility is good by the production method of irradiating ultrasonic waves. This coating solution can be produced. This makes it possible to maintain a dispersed state for a long period of time in the same manner as the above-described coating solution for forming a charge transport layer, and has excellent coating properties and does not cause defects in the coating film. A coating solution for forming a single-layer photosensitive layer can be provided.
The film thickness of the single-layer photoreceptor is suitably about 5 to 100 μm.

  In the photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer. Materials used for the protective layer include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, aryl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, Polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, polyarylate, AS resin, butadiene-styrene copolymer, polyurethane, polychlorinated Examples thereof include resins such as vinyl, polyvinylidene chloride, and epoxy resin.

Further, when the protective layer is used, the protective layer is the outermost layer, and the case where the protective layer forming coating liquid is composed of at least a solvent and one or more kinds of fluorine atom-containing resin fine particles is shown in the present invention. In this way, the dispersion medium is contained in the coating solution and vibrated at high speed to disperse the volume average particle size of the fine particles in the solvent to 10 μm or less, and then the dispersibility is good by a production method in which ultrasonic waves are applied. The coating liquid can be produced. This makes it possible to maintain a dispersed state for a long period of time in the same manner as the above-described coating solution for forming a charge transport layer, and has excellent coating properties and does not cause defects in the coating film. A coating liquid for forming a protective layer can be provided.
Further, the protective layer may contain a filler material as one of the fine particles in order to impart further wear resistance. As the filler, those described above can be used, and these filler materials can be used alone or in combination of two or more.
In addition, the inclusion of a charge transport material in the protective layer is very useful for suppressing the electrical characteristics of the photoreceptor, particularly the deterioration of the photosensitivity during repeated use and the increase in residual potential. This is because the charge can be smoothly transferred to the surface of the photosensitive member by providing the protective layer with charge transportability. As such a charge transporting substance, the charge transporting substance used in the charge transporting layer mentioned above can be used.

Furthermore, various additives may be added to the protective layer of the electrophotographic photoreceptor according to the present invention for the purpose of improving adhesiveness, smoothness, and chemical stability.
The protective layer according to the present invention is formed on the photosensitive layer using a conventional coating method such as dip coating, spray coating, blade coating, knife coating or the like. In particular, dip coating and spray coating are advantageous in terms of mass productivity and coating film quality.
The film thickness of the protective layer is suitably in the range of 0.1 to 10 μm.

The image forming apparatus of the present invention will be described with reference to the drawings.
FIG. 5 is a schematic view for explaining the image forming apparatus of the present invention. Note that the following modifications also belong to the category of the present invention.
As shown in FIG. 5, the image forming apparatus using the electrophotographic photosensitive member according to the present invention includes a drum-shaped photosensitive member (1), a charging charger (3), and a pre-transfer charger (7). And a transfer charger (10), a separation charger (11), a pre-cleaning charger (13), and the like. The shape of the photoreceptor (1) is not limited to a drum shape, and may be, for example, a sheet shape or an endless belt shape. As various chargers, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller can be used.
As the transfer means, the above charger can be generally used, but a combination of a transfer charger and a separation charger as shown in the figure is effective.

Further, light sources such as an image exposure unit (5) and a charge removal lamp (2) include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), and electroluminescence (EL). ) And other luminescent materials can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.
Such a light source or the like can irradiate the photosensitive member with light by providing a transfer step, a static elimination step, a cleaning step, or a pre-exposure step in combination with light irradiation in addition to the steps shown in FIG. .

  The toner developed on the photoreceptor (1) by the developing unit (6) is transferred to the transfer paper (9), but not all is transferred, and the toner is not transferred onto the photoreceptor (1). Remains. Such toner is removed from the photoreceptor by the cleaning brush (14) and the blade (15). Cleaning may be performed by a cleaning brush or a blade alone, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

  When the electrophotographic photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. 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. As this developing means, a known method is applied, and a known method is also used as the charge eliminating means.

  FIG. 6 shows an example of another process using the image forming apparatus according to the present invention. In FIG. 6, a photoconductor (22) has the electrophotographic photoconductor produced in the present invention, is driven by a driving roller (23), is charged by a charging charger (20), and is supplied by a light source (21). Image exposure, development (not shown), transfer using a charger (25), cleaning with a brush (26), and static elimination with a light source (27) are repeated.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.

The process cartridge of the present invention uses the photoreceptor of the present invention, and comprises at least one of charging means, exposure means, developing means, transfer means, and cleaning means, and an electrophotographic photoreceptor, and an image. The process cartridge is detachable from the main body of the forming apparatus.
In FIG. 7, (30) is a photosensitive member, (31) is a charging charger as a charging unit, (32) is a cleaning brush as a cleaning unit, (33) is an image exposure unit where the image exposure unit is in contact, (34) Indicates a developing roller as developing means.
In the present invention, a plurality of components such as the above-described photoreceptor (30), charging means (31), developing means (34), and cleaning means (32) are integrally combined as a process cartridge. The process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  In the image forming apparatus having the process cartridge of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging unit, and then receives image exposure light from an image exposing unit such as slit exposure or laser beam scanning exposure. An electrostatic latent image is sequentially formed on the peripheral surface of the body, and the formed electrostatic latent image is then developed with toner by a developing unit, and the developed toner image is transferred between the photosensitive member and the transfer unit from the paper feeding unit. Then, the image is sequentially transferred to the transfer material fed in synchronization with the rotation of the photosensitive member by the transfer means. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor after the image transfer is cleaned by removing toner remaining after transfer by a cleaning unit, and after being further neutralized, it is repeatedly used for image formation.

(Example 1)
15 parts by weight of alkyd resin (Beckolite M6401-50 (manufactured by Dainippon Ink and Chemicals)), 10 parts by weight of melamine resin (Super Becamine G-821-60 (manufactured by Dainippon Ink and Chemicals)) and 150 parts by weight of methyl ethyl ketone 90 parts by weight of titanium oxide powder (Typale CR-EL (manufactured by Ishihara Sangyo Co., Ltd.)) was added thereto and dispersed for 12 hours by a ball mill to prepare an undercoat layer coating solution.
This was coated on a cylindrical aluminum substrate having a diameter of 30 mm by a dip coating method and dried at 130 ° C. for 20 minutes to form an undercoat layer having a thickness of 3.5 μm.
Next, 4 parts by weight of polyvinyl butyral resin (XYHL (manufactured by UCC)) was dissolved in 150 parts by weight of cyclohexanone, which is shown in the following structural formula (1).

  10 parts by weight was added to the bisazo pigment and dispersed for 48 hours by a ball mill, and further 210 parts by weight of cyclohexanone was added and dispersed for 3 hours. This was taken out into a container and diluted with cyclohexanone so that the solid content was 1.5% by weight. The charge generation layer coating solution thus obtained was applied onto the intermediate layer and dried at 130 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, in 100 parts by weight of tetrahydrofuran, 10 parts by weight of bisphenol Z-type polycarbonate resin and 0.002 parts by weight of silicone oil (KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)) are dissolved. A charge transport layer coating solution was prepared by adding 10 parts by weight of the charge transport material. The charge transport layer coating solution thus obtained was applied onto the charge generation layer by a dip coating method and then dried at 110 ° C. for 20 minutes to form a charge transport layer having a thickness of 20 μm.

  Perfluoroalkoxy resin fine particles (PFA fine particles) 20 parts by weight, 30 wt% fluorine block copolymer liquid (Modiper F210: manufactured by NOF Corporation + solvent: methyl ethyl ketone, xylene) 6 with respect to 70 parts by weight of tetrahydrofuran and 20 parts by weight of cyclohexanone 6 The mixture added with parts by weight was dispersed by applying vibration of 1000 times per minute using a φ1 mm zirconia ball in the vertical direction to the container for 120 minutes. This was used as the dispersion liquid of Example 1. On the other hand, when the volume average particle diameter was measured by a centrifugal particle size distribution measuring device (manufactured by Horiba, Ltd., ultra centrifugal automatic particle size distribution measuring device CAPA-700), it was 3.15 μm. 20 parts by weight of the dispersion was taken, and 120 parts by weight of a bisphenol Z type polycarbonate resin solution having a concentration of 2.0 wt% using 25 parts by weight of tetrahydrofuran and 40 parts by weight of cyclohexanone as a solvent was added to obtain a diluted dispersion. The diluted dispersion was irradiated with ultrasonic waves having a frequency of 28 kHz and 500 w for 10 minutes in an ultrasonic cleaning apparatus to obtain a protective layer coating liquid of Example 1. After the protective layer coating solution of Example 1 was left standing for 1 week, the volume average particle size was determined. The protective layer coating solution of Example 1 is applied onto the charge transport layer by a spray coating method, and then dried at 150 ° C. for 30 minutes to form a protective layer having a thickness of 5 μm. The electrophotographic photoreceptor for Example 1 Was made.

(Example 2)
A dispersion of Example 2 was prepared in the same manner as in Example 1 except that φ2 mm zirconia balls were used as media, and the average particle diameter was measured to be 3.93 μm. The coating liquid of Example 2 was produced from the dispersion liquid of Example 3 in the same manner as in Example 1, and the volume average particle diameter was determined in the same manner as in Example 1. Using the coating liquid of Example 2, an electrophotographic photoreceptor for Example 2 was produced in the same manner as Example 1.

(Example 3)
A dispersion of Example 3 was prepared in the same manner as in Example 1 except that φ6 mm zirconia balls were used as media, and the average particle size was 4.31 μm. The coating liquid of Example 3 was produced from the dispersion liquid of Example 3 in the same manner as in Example 1, and the volume average particle diameter was determined in the same manner as in Example 1. Using the coating liquid of Example 3, an electrophotographic photosensitive member for Example 3 was produced in the same manner as Example 1.

Example 4
The dispersion of Example 4 was prepared in the same manner as in Example 1 except that the frequency was changed to 1000 times per minute instead of 100 times per minute, and the average particle size was 3.89 μm. The coating liquid of Example 4 was produced from the dispersion liquid of Example 4 in the same manner as in Example 1, and the volume average particle diameter was determined in the same manner as in Example 1. Using the coating liquid of Example 4, an electrophotographic photosensitive member for Example 4 was produced in the same manner as Example 1.

(Example 5)
A dispersion of Example 5 was prepared in the same manner as in Example 1 except that the frequency was changed to 1000 times per minute instead of 1000 times per minute, and the average particle size was measured to be 4.22 μm. The coating liquid of Example 5 was produced from the dispersion liquid of Example 5 in the same manner as in Example 1, and the volume average particle diameter was determined in the same manner as in Example 1. Using the coating liquid of Example 5, an electrophotographic photosensitive member for Example 5 was produced in the same manner as Example 1.

(Example 6)
The dispersion liquid of Example 6 was produced in the same manner as in Example 1, and the average particle diameter was measured to be 3.27 μm. A protective layer coating liquid of Example 6 was prepared from the dispersion liquid of Example 6 in the same manner as in Example 1 except that the ultrasonic conditions for irradiation were changed to frequencies of 10 kHz and 500 W instead of the frequencies of 28 kHz and 500 w, The volume average particle diameter was determined in the same manner as in Example 1. An electrophotographic photoreceptor for Example 6 was produced in the same manner as Example 1 using the protective layer coating solution of Example 6.

(Example 7)
The dispersion liquid of Example 7 was produced in the same manner as in Example 1, and the average particle size was 3.19 μm. A protective layer coating solution of Example 7 was prepared from the dispersion of Example 7 in the same manner as in Example 1 except that the irradiated ultrasonic waves were changed to frequencies of 100 kHz and 500 W instead of the frequencies of 28 kHz and 500 W. The volume average particle diameter was determined in the same manner as in Example 1. An electrophotographic photosensitive member for Example 7 was produced in the same manner as Example 1 using the protective layer coating solution of Example 7.

(Example 8)
Example 1 except that the bisphenol Z type polycarbonate resin was added to the dispersion after the PFA fine particles were dispersed in the solvent, but the PFA fine particles were dispersed in the solvent after the bisphenol Z type polycarbonate resin was added to the solvent. A dispersion of Example 8 was prepared in the same manner as described above, and the average particle size was measured to be 3.65 μm. The protective layer coating solution of Example 8 was prepared from the dispersion of Example 8 in the same manner as in Example 1, and the volume average particle size was determined in the same manner as in Example 1. An electrophotographic photoreceptor for Example 8 was produced in the same manner as in Example 1 using the protective layer coating solution of Example 8.

Example 9
A dispersion of Example 9 was prepared in the same manner as in Example 1, and the average particle size was measured to be 3.37 μm. To irradiate a dispersion obtained by adding 120 parts by weight of a bisphenol Z-type polycarbonate resin solution having a concentration of 2.0 wt% using 25 parts by weight of tetrahydrofuran and 40 parts by weight of cyclohexanone as a solvent, to prepare a protective layer coating solution Instead, ultrasonic waves were applied to a dispersion obtained by adding 87.5 parts by weight of a bisphenol Z-type polycarbonate resin solution having a concentration of 4.0 wt% using 25 parts by weight of tetrahydrofuran and 7.5 parts by weight of cyclohexanone as a solvent. A protective layer coating solution of Example 9 was prepared from the dispersion of Example 9 in the same manner as in Example 1 except that 5 parts by weight was added to prepare a protective layer coating solution. The particle size was determined. An electrophotographic photoreceptor for Example 9 was produced in the same manner as in Example 1 using the protective layer coating solution of Example 9.

(Comparative Example 1)
A dispersion of Comparative Example 1 was prepared in the same manner as in Example 1, and the average particle diameter was measured to be 3.26 μm. A protective layer coating solution of Comparative Example 1 was prepared from the dispersion of Comparative Example 1 in the same manner as in Example 1 except that the ultrasonic wave was not irradiated, and the volume average particle size was determined in the same manner as in Example 1. . An electrophotographic photosensitive member for Comparative Example 1 was produced in the same manner as Example 1 using the protective layer coating solution of Comparative Example 1.

(Comparative Example 2)
A dispersion liquid of Comparative Example 2 was produced in the same manner as in Example 1 except that dispersion with a dispersion medium was not performed, and the average particle diameter was measured to be 22.36 μm. The protective layer coating solution of Comparative Example 2 was prepared from the dispersion of Comparative Example 2 in the same manner as in Example 1, and the volume average particle size was determined in the same manner as in Example 1. An electrophotographic photosensitive member for Comparative Example 2 was produced in the same manner as Example 1 using the protective layer coating solution of Comparative Example 2.

(Comparative Example 3)
In the same manner as in Example 1, except that a vibration of 1000 times per minute using a φ1 mm zirconia ball was added and dispersed for 120 minutes, and a vibration of 100 times per minute was applied and dispersed using a φ10 mm zirconia ball for 1 minute. A dispersion liquid of Comparative Example 3 was prepared, and the average particle diameter was measured to be 16.72 μm. The protective layer coating solution of Comparative Example 3 was prepared from the dispersion of Comparative Example 3 in the same manner as in Example 1, and the volume average particle size was determined in the same manner as in Example 1. An electrophotographic photosensitive member for Comparative Example 2 was produced in the same manner as Example 1 using the protective layer coating solution of Comparative Example 3.

The obtained electrophotographic photoreceptors 1 to 9 and comparative electrophotographic photoreceptors 1 to 3 are mounted on a remodeled Ipsio Color 8100 manufactured by Ricoh, and a total of 20,000 sheets are continuously printed. The image after printing 20,000 sheets was evaluated. For printing, a test image having an A4 size and an image area ratio of 5% was output by writing equivalent to 600 dpi.
Table 1 summarizes the average particle diameter measurements of the protective layer coating solutions 1 to 9 and the comparative protective layer coating solution, and the image evaluation results of the electrophotographic photosensitive members 1 to 9 and the comparative electrophotographic photosensitive member.

  The protective layer coating liquids of Examples 1 to 9 were free from defects such as nozzle clogging during spray coating, and the coating properties were good. On the other hand, the protective layer coating solutions of Comparative Examples 1 to 3 were clogged with nozzles during spray coating, and it was impossible to stably perform coating. Moreover, when the protective layer coating liquids of Comparative Examples 1 to 3 were internally circulated, the PFA fine particles were stuck in the piping, resulting in a problem that the solid content concentration of the coating liquid was lowered.

  In the present invention, in the case of a subbing layer, a photosensitive layer, a protective layer, and a function-separated type photosensitive member on a support, on the support of an electrophotographic photosensitive member such as a charge generation layer, a charge transport layer, and an intermediate layer. It can utilize for all layers, such as a layer provided.

1 is a schematic cross-sectional view of an electrophotographic photosensitive member of the present invention. FIG. 5 is a schematic cross-sectional view showing a configuration example of another electrophotographic photosensitive member in the present invention. FIG. 5 is a schematic cross-sectional view showing a configuration example of another electrophotographic photosensitive member in the present invention. FIG. 5 is a schematic cross-sectional view showing a configuration example of another electrophotographic photosensitive member in the present invention. 1 is a schematic diagram for explaining an image forming apparatus of the present invention. It is the figure which showed the example of another process using the image forming apparatus by this invention. It is the figure which showed the example of the shape of the process cartridge regarding this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 20 Charger charger 21 Image exposure unit 22 Photoconductor 23 Driving roller 24 Tension roller 25 Transfer charger 26 Cleaning brush 27 Static elimination light source 28 Driven roller 30 Photoconductor 31 Charging means (charging charger)
32 Cleaning means (cleaning brush)
33 Image exposure unit 34 Developing means (developing roller)

Claims (12)

  A method for producing a coating solution for forming a photosensitive layer of an electrophotographic photoreceptor comprising at least a solvent and fine particles, the dispersion comprising a dispersion medium in the coating solution, and a volume average of the fine particles in the solvent A method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member, wherein the dispersion is irradiated with ultrasonic waves after the particle size is dispersed to 10 μm or less.   2. The method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to claim 1, wherein the coating solution is used for forming an outermost layer of the electrophotographic photosensitive member.   3. The coating for forming a photosensitive layer of an electrophotographic photoreceptor according to claim 1, wherein the fine particles are composed of at least one kind of fine particles and one or more kinds of fluorine atom-containing resin fine particles. Manufacturing method for working fluid.   The method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the dispersion medium is a zirconia ball having a diameter of 0.3 mm or more and 5 mm or less.   When the dispersion medium is used to disperse the volume average particle diameter of the fine particles in the solvent to 10 μm or less, at least in a container containing the dispersion medium, the solvent, and the fine particles at a frequency of 100 to 2000 times per minute. 5. The method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to claim 1, wherein the dispersion treatment is performed by applying the following high-speed vibration.   The method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the ultrasonic wave applied to the dispersion liquid has a frequency of 15 kHz to 60 kHz.   The coating liquid contains a binder resin, and after dispersing the volume average particle diameter of the fine particles in the solvent to 10 μm or less, the binder resin is added, and then, ultrasonic waves are irradiated. A method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to any one of claims 1 to 6.   The coating solution is a coating solution in which the solid content concentration at the time of fine particle dispersion and the solid content concentration at the time of coating are different, and after being diluted to the solid content concentration at the time of coating, it is irradiated with ultrasonic waves. The method for producing a coating solution for forming a photosensitive layer of an electrophotographic photosensitive member according to any one of claims 1 to 7.   9. An electrophotographic photosensitive member having one or more photosensitive layers on a conductive support, wherein at least one photosensitive layer is produced by the production method according to any one of claims 1 to 8. An electrophotographic photosensitive member formed using a coating solution.   An image forming apparatus comprising at least an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 9. .   The process cartridge for an image forming apparatus according to claim 10, comprising at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, and an electrophotographic photosensitive member. A coating solution for forming a photosensitive layer of an electrophotographic photosensitive member, which is produced by the production method according to claim 1.

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