JP4262107B2 - Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus, and method of manufacturing electrophotographic photosensitive member - Google Patents

Description

The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member, and a method for manufacturing the electrophotographic photosensitive member .

  The electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process. Further, the surface of the electrophotographic photosensitive member is subjected to electric external force and mechanical external force such as charging, exposure (image exposure), development with toner, transfer to a transfer material (paper, etc.) and cleaning. Durability is also required. Specifically, durability against wear and scratches caused by the contact members rubbing the surface of the electrophotographic photosensitive member during charging, transfer, and cleaning, as well as potential characteristics due to ozone and charged products generated during charging. Durability against deterioration is required. Further, there is a problem that toner adheres to the surface of the electrophotographic photosensitive member due to repeated development and cleaning, and good cleaning properties are also required.

  In order to satisfy the characteristics required for the above-described electrophotographic photosensitive member, various devices have been made on the surface layer of the electrophotographic photosensitive member.

  As one method, an attempt is made to provide a protective layer mainly composed of a resin on the photosensitive layer. For example, Japanese Patent Application Laid-Open No. 56-042863 (Patent Document 1) and Japanese Patent Application Laid-Open No. 53-103741 (Patent Document 2) provide an electrophotographic photosensitive film by providing a protective layer mainly composed of a curable resin. Techniques for improving the hardness and wear resistance of the body surface are disclosed.

  In addition, in order to obtain an excellent output image, the protective layer of the electrophotographic photoreceptor is required not only to have properties such as high hardness and excellent wear resistance but also to have an appropriate volume resistivity of the protective layer. . That is, when the volume resistivity of the protective layer is too low, an electrostatic latent image formed on the surface of the electrophotographic photosensitive member by charging and exposure flows in the surface direction in the protective layer, and blurring or blurring of the image occurs. Problems occur. On the other hand, when the volume resistivity of the protective layer is too high, charging and exposure are repeated, so that charges are accumulated in the protective layer, which increases the so-called residual potential. Is not stable, so the image quality becomes unstable.

In order to solve these problems, for example, in Japanese Patent Application Laid-Open No. 57-030843 (Patent Document 3), the volume resistivity of the protective layer is obtained by adding metal oxide particles as conductive particles to the protective layer. Techniques for controlling are disclosed. The appropriate volume resistivity of the protective layer of the electrophotographic photosensitive member is 1 × 10 ¹⁰ to 1 × 10 ¹⁵ Ω · cm.

  In addition, since the water absorption of the surface of the metal oxide is high and the volume resistivity of the protective layer changes depending on the degree of water absorption, the volume resistivity of the protective layer depends on the environment, and the metal oxide is used as conductive particles. It was difficult to keep the volume resistivity of the protective layer in an appropriate range under any environment only by adding particles.

  In order to solve this problem, for example, in Japanese Patent Application Laid-Open No. 62-295066 (Patent Document 4), metal particles whose water-repellent treatment has improved dispersibility and moisture resistance in a binder resin, A technique for controlling the volume resistivity of a protective layer by providing a protective layer in which metal oxide particles are dispersed is disclosed.

  However, by performing water-repellent treatment, the volume resistivity of the protective layer under low humidity tends to be extremely high compared to the volume resistivity of the protective layer under normal humidity, and the volume resistivity of the protective layer under any environment. It was difficult to keep the rate in the proper range.

With recent higher image quality and higher durability, electrophotographic photoreceptors having higher durability and capable of stably providing excellent images are being studied. In addition, an electrophotographic apparatus that employs a digital electrostatic latent image has been provided, and higher definition and dot reproducibility of the image have been further required.
Japanese Patent Laid-Open No. 56-042863 JP-A-53-103741 Japanese Patent Laid-Open No. 57-030843 JP-A-62-295066

  If the volume resistivity of the surface layer of the electrophotographic photosensitive member is not appropriate, formation of the electrostatic latent image will be insufficient, or the formed electrostatic latent image will be destroyed by blurring, so accurate dot reproduction will be possible. become unable.

  As described above, as the surface layer of the electrophotographic photosensitive member, a protective layer in which metal particles or metal oxide particles whose water repellency treatment has improved the dispersibility and moisture resistance is dispersed is provided in the binder resin. However, the volume resistivity of the protective layer under low humidity tends to be extremely high compared to the volume resistivity of the protective layer under normal humidity, and the volume resistivity of the protective layer should be kept in an appropriate range under any environment. Was difficult.

  In addition, when the water repellent treatment of the conductive particles is not uniform, the volume resistivity of the protective layer becomes non-uniform (uneven), and the density unevenness of the output image and white spots may occur.

The object of the present invention is to provide an electrophotographic photosensitive member containing conductive particles whose surface layer has been subjected to a water repellent treatment using a water repellent treatment agent, so that the environmental variation of the volume resistivity of the surface layer is small and can be protected under any environment. It is possible to maintain the volume resistivity of the layer accurately and appropriately, and there are no image defects such as blurring, blurring, unevenness, and whiteout, and the output image has high definition, dot reproducibility, electrical external force, and mechanical external force. It is an object of the present invention to provide an electrophotographic photosensitive member and a method for producing the same.

  Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

The present invention, support and have a photosensitive layer on the support, and an electrophotographic photosensitive member is a layer containing a surface layer Gashirube conductive particles,
When the conductive particles, a drying loss (mass after drying 2 hours conductive particles outstanding water repellent treatment at 105 ° C. and Md, the mass prior to drying was M, [(M-Md) / M] × 100 and obtained by subjecting the non-water-repellent treated conductive particles having a loss on drying [mass%] of 2 to 7 mass% to a water-repellent treatment using a water-repellent treatment agent. An electrophotographic photosensitive member characterized by being water-repellent treated conductive particles .

Further, the present invention integrally supports the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from the main body of the electrophotographic apparatus. It is a process cartridge characterized by being.
The present invention also provides an electrophotographic apparatus comprising the electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit.
Further, the present invention provides a method for producing an electrophotographic photosensitive member having a support and a photosensitive layer on the support, and the surface layer is a layer containing conductive particles.
Loss on drying (calculated as [(M−Md) / M] × 100, where Md is the mass after drying the non-water-repellent conductive particles at 105 ° C. for 2 hours and M is the mass before drying) Water-repellent treatment using a water-repellent treatment agent to non-water-repellent conductive particles having a loss on drying [mass%] of 2 to 7 mass%. A water repellent treatment step for obtaining particles;
And a surface layer forming step of forming the surface layer using the water-repellent treated conductive particles .

According to the present invention, in an electrophotographic photosensitive member containing conductive particles whose surface layer has been subjected to water repellent treatment using a water repellent treatment agent, the environmental variation of the volume resistivity of the surface layer is small and can be protected under any environment. It is possible to maintain the volume resistivity of the layer accurately and appropriately, and there are no image defects such as blurring, blurring, unevenness, and whiteout, and the output image has high definition, dot reproducibility, electrical external force, and mechanical external force. It is possible to provide an electrophotographic photosensitive member and a method for producing the same , which are compatible with the durability against the above.

  Further, according to the present invention, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member can be provided.

  By adopting the above-described configuration of the present invention, even in an electrophotographic photosensitive member containing conductive particles whose surface layer has been subjected to water-repellent treatment using a water-repellent treatment agent, environmental fluctuation of the volume resistivity of the surface layer is small, It is possible to maintain the volume resistivity of the protective layer accurately and appropriately in any environment, and there is no image defect such as blurring, blurring, unevenness, and whiteout, and the output image has high definition, dot reproducibility, and electrical The reason why both external force and durability against mechanical external force are compatible is presumed as follows.

  That is, when the conductive particles are water-repellent treated with a water-repellent treatment agent, the surface of the conductive particles before the water-repellent treatment is not uniformly treated with the water-repellent treatment agent, that is, a lot of water-repellent treatment is performed. If there is a part and a part that is water-repellent treatment / part that is not water-repellent at all, unevenness in how water-repellent treatment is performed becomes uneven in volume resistivity. Phenomena such as dispersibility changes when dispersing conductive particles occur, causing irregularities in the volume resistivity of the conductive particles themselves and micro irregularities in the volume resistivity of the surface layer containing the conductive particles. The above problem occurs.

  When performing the water repellent treatment with the water repellent treatment agent, if the above conditions of the present invention are not satisfied, the distance between the conductive particles and the water repellent treatment agent is not appropriate, and it is considered that the environmental fluctuation of the volume resistivity increases.

  That is, by adopting the above-described configuration of the present invention, the conductive particles can be uniformly water-repellent treated, and the volumetric resistivity unevenness of the conductive particles themselves or the microscopic unevenness of the volume resistivity of the surface layer containing the conductive particles. Therefore, the above problem can be solved.

  Examples of the conductive particles used in the present invention include metal particles, metal oxide particles, and carbon black.

  Examples of the metal particles include particles such as aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, and those obtained by depositing these metals on the surface of particles such as plastic.

  Examples of the metal oxide particles include zinc oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. Can be mentioned.

  These particles may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.

  In the present invention, metal oxide particles are preferred from the viewpoint of transparency.

  The average particle diameter of the conductive particles used in the present invention is preferably 0.3 μm or less from the viewpoint of the transparency of the surface layer of the electrophotographic photosensitive member and the uniformity of the volume resistivity of the surface layer, in particular 0. More preferably, it is 1 μm or less.

In the present invention, the conductive particles refer to particles having a volume resistivity of 10 ² Ω · cm or less. This “volume resistivity” can be measured as follows.

First, a sample is formed into a disk-shaped pellet having a diameter of 4 cm and a thickness of 0.2 cm by applying a pressure of 100 kg / cm ² . Next, the volume resistivity (Ω · cm) of the disk-shaped pellet is measured using Hiresta AP (manufactured by Mitsubishi Oil Chemical Co., Ltd.).

In the present invention, the conductive particles are preferably metal particles or metal oxide particles, more preferably metal oxide particles, and even more preferably tin oxide particles. The tin oxide particles are preferably tin oxide particles doped with antimony oxide. Of the tin oxides, SnO ₂ is preferable. Of the antimony oxides, Sb ₂ O ₅ is preferable.

  The conductive particles used in the surface layer of the electrophotographic photosensitive member of the present invention are conductive particles that have been subjected to a water repellent treatment using a water repellent treatment agent as described above. The amount is preferably 8 to 30% by mass with respect to the mass of the conductive particles before the water repellent treatment. When the amount is less than 8% by mass, the amount of the water repellent agent covering the surface of the conductive particles is small, and it may be easy to absorb moisture or the volume resistivity may be too low. When it exceeds 30% by mass, the amount of the water-repellent treatment agent covering the surface of the conductive particles is large, and the volume resistivity may be too high.

  Moreover, as a water-repellent processing agent to be used, a silane coupling agent, a siloxane compound, and a fluorine atom containing compound are preferable. Of the fluorine atom-containing compounds, fluorine atom-containing silane coupling agents, fluorine-modified silicone oils, and fluorine atom-containing surfactants are preferred.

  Specific examples of the fluorine atom-containing silane coupling agent are given below.

  Specific examples of the fluorine-modified silicone oil are given below.

(In the formula (SO-1), n ^so1 and n ^so2 are each independently a positive integer.)
Specific examples of the fluorine atom-containing surfactant will be given below.

In (the formula (SA-1) ~ (SA -25), X sa _{is, -CF 3, -C 4 F 9} , .R represents a monovalent fluorocarbon groups such as -C _{8 F 17} ^sa is An alkylene group, an arylene group or an alkylene arylene group, and when there are a plurality of R ^{sa s in the} formula, they may be the same or different.)
Specific examples of the siloxane compound are given below.

(In the above formula (SX-1), X ^sx represents a hydrogen atom or a methyl group. The plurality of X ^sx may be the same or different, but hydrogen for all of X ^sx (The atomic ratio is 0.1 to 50%, and n ^sx is a positive integer.)
The weight average molecular weight of the siloxane compound having the structure represented by the formula (SX-1) is preferably 200 to 30000.

  The method of water-repellent treatment of conductive particles using a water-repellent treatment agent is roughly classified into two types, a wet method and a dry method. In terms of stability of the treatment reaction and ease of handling, A wet method is preferred. In the case where the conductive particles are subjected to water repellent treatment by a wet method, for example, the following can be performed.

  That is, the conductive particles before the water repellent treatment and the water repellent treatment agent are mixed and dispersed in a solvent, and the water repellent treatment agent is adhered to the surface of the conductive particles. Examples of the dispersion method include a dispersion method using a ball mill, a sand mill, or the like. After dispersion of the conductive particles, the solvent is removed from the dispersion, and the water repellent treatment agent is fixed to the surface of the conductive particles. Moreover, you may heat-process further after this as needed. Further, a catalyst for promoting the reaction may be added to the dispersion. Furthermore, if necessary, the conductive particles after the water repellent treatment may be further pulverized.

In the case where the conductive particles are SnO ₂ particles doped with Sb ₂ O ₅ and the water repellent agent is a fluorine atom-containing silane coupling agent having a structure represented by the above formula (SC-1), This will be described more specifically.

(Water repellent treatment example 1)
The following steps (i) to (vi) are performed.

(I) The loss on drying of the SnO ₂ particles doped with Sb ₂ O ₅ is confirmed. When the loss on drying of the SnO ₂ particles doped with Sb ₂ O ₅ is less than 2% by mass, the loss on drying becomes 2 to 7% by mass by exposing the particles to an atmosphere having a humidity of 60% RH or more. Adjust to. On the other hand, when the loss on drying of the SnO ₂ particles doped with Sb ₂ O ₅ exceeds 7% by mass, the drying loss is adjusted to 2 to 7% by mass using a dryer such as a vacuum dryer. .

(Ii) SnO ₂ particles doped with Sb ₂ O ₅ , toluene and methanol having approximately the same mass as the particles, and 8 to 30% by mass of the above formula (SC-1) with respect to the mass of the particles Fluorine atom-containing silane coupling agent having a structure as described above is put into an ultramixer and sufficiently stirred. The stirred liquid mixture is sent to a continuous bead mill, and dispersed and wet pulverized.

  (Iii) The mixed liquid is recovered from the bead mill with a toluene / methanol mixed solvent having a mass ratio of 1: 1.

  (Iv) Perform vacuum distillation with a vacuum pump while heating.

  (V) Curing is performed at 150 ° C. for 2 hours.

  (Vi) Pulverization is performed with a dry pulverizer to obtain water-repellent conductive particles.

(Water repellent treatment example 2)
In the water repellent treatment example 1, the process of (ii) was changed as follows, and was the same as the water repellent treatment example 1.

That is,
(Ii) Toluene and methanol having substantially the same mass as the SnO ₂ particles doped with Sb ₂ O ₅ are put into an ultramixer, and then 8 to 30% by mass of the above formula (SC-1 based on the mass of the particles) ), A fluorine atom-containing silane coupling agent having a structure represented by the following formula is added, then 2 to 10% by mass of water is added to the mass of the particles, and finally SnO ₂ doped with Sb ₂ O ₅ is added. Put the particles and stir well. The stirred liquid mixture is sent to a continuous bead mill, and dispersed and wet pulverized.

(Water repellent treatment example 3)
In the water repellent treatment example 1, the process of (ii) was changed as follows, and was the same as the water repellent treatment example 1.

That is,
(Ii) Put toluene and methanol of approximately the same mass as the SnO ₂ particles doped with Sb ₂ O ₅ into the ultramixer, then add 2-10% water by weight with respect to the mass of the particles, then , Put SnO ₂ particles doped with Sb ₂ O ₅ and stir well. Next, the fluorine atom containing silane coupling agent which has a structure shown by the said Formula (SC-1) of 8-30 mass% with respect to the mass of this particle | grain is added, and it fully stirs again. The stirred liquid mixture is sent to a continuous bead mill, and dispersed and wet pulverized.

(Water repellent treatment example 4)
In the water repellent treatment example 2, it is the same as the water repellent treatment example 2 except that the step (i) is omitted.

(Water repellent treatment example 5)
In the water repellent treatment example 3, it is the same as the water repellent treatment example 3 except that the step (i) is omitted.

  That is, as in water repellent treatment examples 4 and 5, in the step (ii), water repellent treatment example 1 is performed by adding 2 to 10% by mass of water to the mass of the conductive particles before the water repellent treatment. Even if the step (i) is omitted, the same effect as that obtained when the step (i) is performed can be obtained.

Regarding the case where the conductive particles are not SnO ₂ particles doped with Sb ₂ O ₅ , and the case where the water repellent treatment agent is not a fluorine atom-containing silane coupling agent having a structure represented by the above formula (SC-1). Alternatively, the water repellent treatment of the conductive particles can be performed in the same manner as described above.

  Next, the configuration of the electrophotographic photosensitive member used in the present invention will be described.

  As described above, the electrophotographic photosensitive member used in the present invention is an electrophotographic photosensitive member having a photosensitive layer on a support.

  The photosensitive layer is separated into a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material even if it is a single layer type photosensitive layer containing the charge transporting material and the charge generating material in the same layer. A laminated type (functional separation type) photosensitive layer may be used, but a laminated type photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. The laminated photosensitive layer has a normal layer type photosensitive layer laminated in the order of the charge generation layer and the charge transport layer from the support side, and a reverse layer type photosensitive layer laminated in the order of the charge transport layer and the charge generation layer from the support side. However, a normal photosensitive layer is preferred from the viewpoint of electrophotographic characteristics.

  When the photosensitive layer is a surface layer of an electrophotographic photosensitive member, when the photosensitive layer is a single layer type photosensitive layer, the single layer type photosensitive layer is a surface layer of the electrophotographic photosensitive member, and the photosensitive layer is a normal layer. In the case of the type photosensitive layer, the charge transport layer is the surface layer of the electrophotographic photoreceptor, and in the case of the reverse layer type photosensitive layer, the charge generation layer is the surface layer of the electrophotographic photoreceptor.

  In the present invention, as described above, the layer serving as the surface layer of the electrophotographic photosensitive member contains conductive particles that have been subjected to water repellent treatment using a water repellent treatment agent. Therefore, when the surface layer of the electrophotographic photosensitive member is a single layer type photosensitive layer, the single layer type photosensitive layer must be a layer containing conductive particles that have been subjected to water repellent treatment using a water repellent treatment agent. Don't be. When the surface layer of the electrophotographic photosensitive member is a charge generation layer, the charge generation layer must be a layer containing conductive particles that have been subjected to a water repellent treatment using a water repellent treatment agent. When the surface layer of the electrophotographic photosensitive member is a charge transport layer, the charge transport layer must be a layer containing conductive particles that have been subjected to water repellent treatment using a water repellent treatment agent.

  In addition to the photosensitive layer described above, a layer (hereinafter also referred to as a protective layer) intended to increase the mechanical strength of the surface of the electrophotographic photosensitive member is provided on the photosensitive layer, and is provided on the electrophotographic photosensitive layer. It may be a body surface layer. From the viewpoint of improving the mechanical durability of the electrophotographic photosensitive member, it is preferable to provide a protective layer. Since the protective layer is a surface layer of the electrophotographic photosensitive member, in the present invention, it must be a layer containing conductive particles that have been subjected to water repellent treatment using a water repellent treatment agent.

  FIG. 1 shows an example of the layer structure of the electrophotographic photosensitive member of the present invention.

  In the electrophotographic photosensitive member having the layer structure shown in FIG. 1A, a photosensitive layer 104 is provided on a support 101, and a water-repellent treatment is performed thereon using a water-repellent treatment agent as a surface layer. A layer 105 containing the conductive particles formed is provided. Further, in the electrophotographic photosensitive member having the layer structure shown in FIG. 1B, a charge generation layer 1041 and a charge transport layer 1042 are provided in this order on a support 101, and further, a repellent layer is formed thereon as a surface layer. A layer (protective layer) 105 containing conductive particles subjected to water repellent treatment using a water treatment agent is provided. Further, as shown in FIG. 1C, a conductive layer 102 and an intermediate layer 103 which will be described later may be provided between the support 101 and the charge generation layer 1041 (photosensitive layer).

  In addition, the electrophotographic photosensitive member having the layer structure shown in FIG. 1D is provided with a charge generation layer 1041 on a support 101, and a charge transport material and a water repellent treatment agent are formed thereon as a surface layer. A layer 105 ′ containing conductive particles subjected to water repellency treatment using is directly provided.

  Hereinafter, as a preferable layer structure of the electrophotographic photoreceptor, an electrophotographic photoreceptor having a charge generation layer, a charge transport layer, and a protective layer in this order on a support will be described as an example.

  As a support body, what is necessary is just to have electroconductivity (conductive support body), for example, metal supports, such as aluminum, an aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have the layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. Also, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, a plastic support having a conductive binder resin, etc. Can also be used. Examples of the shape of the support include a drum shape (cylindrical shape) and a belt shape.

  A conductive layer may be provided between the support and the photosensitive layer (charge generation layer) or an intermediate layer, which will be described later, for the purpose of preventing interference fringes due to scattering of laser light or the like, and for covering scratches on the support. . The conductive layer can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 1 to 40 μm, and more preferably 2 to 20 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown. The intermediate layer can be formed using materials such as casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, and aluminum oxide. The thickness of the intermediate layer is preferably 5 μm or less, and more preferably 0.1 to 3 μm.

  A charge generation layer is provided on the support, the conductive layer, or the intermediate layer.

  Examples of the charge generation material used in the charge generation layer include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, perylene acid anhydride, Perylene pigments such as peryleneimide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, inorganic substances such as selenium, selenium-tellurium and amorphous silicon And quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinone imine dyes, styryl dyes, cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  Examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, Examples include silicone resins, polysulfone resins, styrene-butadiene copolymer resins, alkyd resins, epoxy resins, urea resins, vinyl chloride-vinyl acetate copolymer resins, and the like. These can be used singly or in combination of two or more as a mixture or copolymer.

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons and aromatic compounds.

  The charge generation layer can be formed by applying and drying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent. Examples of the dispersion method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, a roll mill and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.3 to 1: 4 (mass ratio).

  When applying the coating solution for the charge generation layer, for example, a coating method such as a dip coating method (a dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, or a blade coating method is used. be able to.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.05 to 3 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  A charge transport layer is provided on the charge generation layer.

  Examples of the charge transport material used for the charge transport layer include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge transport layer include acrylic resin, styrene resin, polyester resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyphenylene oxide resin, epoxy resin, Examples include polyurethane resins, alkyd resins, and unsaturated resins. In particular, polymethyl methacrylate resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polycarbonate resin, polyarylate resin, diallyl phthalate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The charge transport layer can be formed by applying and drying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the charge transport layer coating solution include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, and chlorobenzene. , Hydrocarbons substituted with halogen atoms such as chloroform and carbon tetrachloride are used.

  When applying the coating solution for the charge transport layer, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like is used. be able to.

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  A protective layer as a surface layer of the electrophotographic photosensitive member is provided on the charge transport layer.

  Examples of the binder resin used for the protective layer include acrylic resin, polyester resin, polycarbonate resin, polystyrene resin, cellulose resin, polyethylene resin, polypropylene resin, polyurethane resin, epoxy resin, silicone resin, and polyvinyl chloride resin. . Among these, curable resins are preferable from the viewpoints of the surface hardness of the electrophotographic photosensitive member, wear resistance, dispersibility of conductive particles, and dispersion stability.

  When a curable resin is used as the binder resin for the protective layer, the protective layer is obtained by dispersing conductive particles that have been subjected to water repellent treatment with a water repellent treatment agent together with the binder resin monomer / oligomer and solvent. It can be formed by applying a layer coating solution and curing it by heat or light.

  The monomer / oligomer curable by heat, light, or the like is, for example, a monomer / oligomer having a functional group that causes a polymerization reaction by energy such as heat or light at the end of the monomer / oligomer. Large molecules having 2 to 20 repeating structural units are oligomers, and one molecule is a monomer.

  Examples of the functional group causing the polymerization reaction include ring-opening polymerization of a group having a carbon-carbon double bond such as acryloyl group, methacryloyl group, vinyl group, and acetophenone group, silanol group, and cyclic ether group. Groups, and those in which two or more kinds of molecules react to cause polymerization, such as phenol + formaldehyde.

The ratio between the binder resin and the conductive particles is related to the volume resistivity of the protective layer, and the volume resistivity of the protective layer is in the range of 10 ¹⁰ to 10 ¹⁵ Ω · cm. It is preferable to determine the proportion of particles.

  In the protective layer, additives such as a coupling agent and an antioxidant may be added for the purpose of improving dispersibility, binding properties, and weather resistance.

  The protective layer may contain fluorine atom-containing resin particles for the purpose of improving the releasability, water repellency and surface lubricity of the surface of the electrophotographic photosensitive member. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these And particles such as a copolymer. One or more of these are appropriately selected and used. Among these fluorine atom-containing resin particles, ethylene tetrafluoride resin particles and vinylidene fluoride resin particles are preferable.

  The proportion of the fluorine atom-containing resin particles in the protective layer is preferably 70% by mass or less, more preferably 10 to 60% by mass, based on the total mass of the protective layer. If the ratio of the fluorine atom-containing resin particles is too high, the mechanical strength of the protective layer may be lowered.

  FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis 2.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3, and then subjected to slit exposure, laser beam scanning exposure, or the like. Exposure light (image exposure light) 4 output from exposure means (not shown) is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed with toner contained in the developer of the developing unit 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it is repeatedly used for image formation. As shown in FIG. 2, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 2, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5 and the cleaning unit 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is used by using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”.

( Reference Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 254 mm was used as a support.

Next, 10 parts of SnO ₂ coated treated barium sulfate (conductive particles), 2 parts of titanium oxide (for volume resistivity adjustment), phenol resin (trade name: Pryofen J-325, manufactured by Dainippon Ink & Chemicals, Inc.) ) 2 parts, 0.001 part of silicone oil (leveling agent) and 16 parts of methanol / 16 parts of methoxypropanol were dispersed for 20 hours in a sand mill using glass beads with a diameter of 1 mm for the conductive layer. A coating solution was prepared.

  This conductive layer coating solution was applied by dip coating on a support and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

  Next, 10 parts of copolymerized polyamide resin (trade name: Amilan CM-8000, manufactured by Toray Industries, Inc.), 30 parts of methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Co., Ltd.) Then, it was dissolved in a mixed solvent of methanol 400 parts / n-butanol 200 parts to prepare an intermediate layer coating solution.

  This intermediate layer coating solution was dip-coated on the conductive layer and dried in hot air at 90 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.66 μm.

  Next, a crystalline oxytitanium phthalocyanine (charge) having strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. (Generating material) 3.24 parts, 2 parts of butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts of cyclohexanone were dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm. Next, 90 parts of ethyl acetate was added to prepare a coating solution for charge generation layer.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried in hot air at 82 ° C. for 15 minutes to form a charge generation layer having a thickness of 0.18 μm.

  Next, 7 parts of a compound (charge transport material) having a structure represented by the following formula:

Further, 10 parts of bisphenol Z-type polycarbonate (trade name: Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is dissolved in a mixed solvent of 40 parts of monochlorobenzene / 30 parts of dichloromethane to prepare a coating solution for a charge transport layer. did.

  This charge transport layer coating solution was dip coated on the charge generation layer and dried at 110 ° C. for 60 minutes to form a charge transport layer having a thickness of 18 μm.

Next, SnO ₂ particles doped with Sb ₂ O ₅ subjected to water repellent treatment according to water repellent treatment example 4 (conductive particles, average particle size: 0.02 μm, having a structure represented by the above formula (SC-1)) The proportion of fluorine atom-containing silane coupling agent is 13% by mass with respect to the mass of the particles, the proportion of water is 4% by mass with respect to the mass of the particles) and 120 parts of acrylic having a structure represented by the following formula: 43.2 parts of resin monomer,

Then, 210 parts of ethanol was dispersed with a sand mill apparatus for 90 hours to obtain a dispersion.

  40.8 parts of ethylene tetrafluoride resin particles (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) are added to this dispersion, and the mixture is further dispersed for 2 hours with a sand mill device. 6.48 parts of diethylthioxanthone (photopolymerization initiator) and 2.16 parts of 4,4′-bis (diethylamino) benzophenone (initiator aid) were added and dissolved to prepare a coating solution for a protective layer.

This protective layer coating solution is dip coated on the charge transport layer, irradiated with UV light at a light intensity of 1.20 × 10 ⁻⁵ W / m ² for 30 seconds with a metal halide lamp, photocured, and then 120 The film was dried with hot air at 1 ° C. for 1 hour and 40 minutes to form a protective layer having a thickness of 6 μm.

  In this way, an electrophotographic photoreceptor having a protective layer as a surface layer was produced.

  Separately from the electrophotographic photoreceptor, the following sample (protective layer volume resistivity measurement sample) was prepared, and the volume resistivity of the protective layer was measured as follows.

  First, a plurality of samples were prepared in which a protective layer having a thickness (T) of 4 μm was provided on a comb-type gold electrode having an interelectrode distance (D) of 180 μm and a length (L) of 5.9 cm.

  Next, the sample is left overnight in a 23 ° C./5.5% RH environment, a 23 ° C./50% RH environment, and a 28.5 ° C./70% RH environment. A current value I [A] was measured with a pA (picoampere) meter when a DC voltage V [V] of 100 V was applied between them. The volume resistivity ρv is derived from the following equation. The results are shown in Table 1.

(In the above formula, T [cm] × L [cm] is the cross-sectional area of the sample, and D [cm] is the length of the sample)
Regarding the environmental variation rate evaluation (R _L / _RN evaluation and R _N / _RH evaluation) of the volume resistivity in Table 1, the volume resistivity under the environment of 23 ° C./5.5% RH is expressed as R _L , 23 ° C. / the volume resistivity under 50% RH environment _R N, when the volume resistivity under 28.5 ° C. / 70% RH environment and _{R H,} which is R L / _{R N} and _R N / _{R H.}

  The produced electrophotographic photosensitive member is allowed to stand overnight in a 23 ° C./5.5% RH environment, a 23 ° C./50% RH environment, and a 28.5 ° C./70% RH environment. It was mounted on a printer (trade name: LBP-EX, manufactured by Canon Inc., configuration shown in FIG. 2), and the surface potential (bright part potential Vl) was measured. After measuring the initial surface potential, endurance test that repeats 20,000 sheets passing through and printing is performed, and the output image is evaluated, and A (from there is no image defect such as blurring, blurring, unevenness, whiteout), Ranking was performed in the order of B (there is a slight image defect such as blur, blur, unevenness, white spot) and C (there is an image defect such as blur, blur, unevenness, white spot).

  The results are shown in Table 1.

( Reference Example 2)
In Reference Example 1, a sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as Reference Example 1 except that the following points were changed. The results are shown in Table 1.

-Conductive particles in protective layer The water-repellent treatment of the conductive particles was changed from the water-repellent treatment example 4 to the water-repellent treatment example 5. Further, the water repellent treatment agent is changed from a fluorine atom-containing silane coupling agent having a structure represented by the above formula (SC-1) to a siloxane compound having a structure represented by the above formula (SX-1) (average of n ^sx 21 and the ratio of hydrogen atoms to all of X ^sx was changed to 43.5%). The ratio of the siloxane compound having the structure represented by the formula (SX-1) is 20% by mass with respect to the mass of the conductive particles before the water repellent treatment, and the ratio of water is the mass of the conductive particles before the water repellent treatment. The content was 7% by mass.

(Example 3)
In Reference Example 1, a sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as Reference Example 1 except that the following points were changed. The results are shown in Table 1.

-Conductive particles in the protective layer The water-repellent treatment of the conductive particles was changed from the water-repellent treatment example 4 to the water-repellent treatment example 1. The SnO ₂ particles doped with Sb ₂ O ₅ were exposed to an atmosphere of 80% humidity for 8 hours before the water repellent treatment to adjust the loss on drying to 4% by mass. The ratio of the fluorine atom-containing silane coupling agent having the structure represented by the above formula (SC-1) was 13% by mass with respect to the mass of the conductive particles before the water repellent treatment.

(Example 4)
In Example 3, electrophotography was carried out in the same manner as in Example 3 except that the loss on drying was adjusted to 2% by mass by changing the time during which the conductive particles before the water repellent treatment were exposed to an atmosphere of 80% humidity. Samples for measuring the volume resistivity of the photoreceptor and the protective layer were prepared and evaluated. The results are shown in Table 1.

(Example 5)
In Example 3, electrophotography was performed in the same manner as in Example 3 except that the loss on drying was adjusted to 7% by mass by changing the time during which the conductive particles before the water repellent treatment were exposed to an atmosphere having a humidity of 80% RH. Samples for measuring the volume resistivity of the photoreceptor and the protective layer were prepared and evaluated. The results are shown in Table 1.

( Reference Example 6)
In Reference Example 1, a sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as Reference Example 1 except that the following points were changed. The results are shown in Table 1.

・ Conductive particles in the protective layer
Instead of 120 parts of the conductive particles used in Reference Example 1, SnO ₂ particles doped with Sb ₂ O ₅ subjected to water repellent treatment according to water repellent treatment example 4 (conductive particles, average particle size: 0.02 μm, above) 40 parts by weight of the fluorine atom-containing silane coupling agent having the structure represented by the formula (SC-1) is 13% by mass with respect to the mass of the particles, and the ratio of water is 4% by mass with respect to the mass of the particles And SnO ₂ particles doped with Sb ₂ O ₅ subjected to water repellent treatment according to the water repellent treatment example 4 (conductive particles, average particle size: 0.02 μm, the water repellent treatment agent is represented by the above formula (SX-1). (The average of n ^sx is 21, and the ratio of hydrogen atoms to the total of X ^sx is 43.5%), the ratio of the siloxane compound is 25% by mass with respect to the mass of the particles, water Is 5% by mass with respect to the mass of the particles And 80 parts in combination.

( Reference Example 7)
Reference Example 1 except that the ratio of the fluorine atom-containing silane coupling agent used in the water-repellent treatment of the conductive particles in Reference Example 1 was changed to 8% by mass with respect to the mass of the conductive particles before the water-repellent treatment. In the same manner as described above, an electrophotographic photosensitive member and a protective layer volume resistivity measurement sample were prepared and evaluated. The results are shown in Table 1.

( Reference Example 8)
Reference Example 1 except that the ratio of the fluorine atom-containing silane coupling agent used in the water-repellent treatment of the conductive particles in Reference Example 1 was changed to 30% by mass with respect to the mass of the conductive particles before the water-repellent treatment. In the same manner as described above, an electrophotographic photosensitive member and a protective layer volume resistivity measurement sample were prepared and evaluated. The results are shown in Table 1.

( Reference Example 9)
In Reference Example 1, electrophotography was performed in the same manner as in Reference Example 1, except that the ratio of water used for the water repellent treatment of the conductive particles was changed to 2% by mass with respect to the mass of the conductive particles before the water repellent treatment. Samples for measuring the volume resistivity of the photoreceptor and the protective layer were prepared and evaluated. The results are shown in Table 1.

( Reference Example 10)
In Reference Example 1, electrophotography was performed in the same manner as in Reference Example 1, except that the ratio of water used for the water repellent treatment of the conductive particles was changed to 10% by mass with respect to the mass of the conductive particles before the water repellent treatment. Samples for measuring the volume resistivity of the photoreceptor and the protective layer were prepared and evaluated. The results are shown in Table 1.

(Example 11)
In Reference Example 1, a sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as Reference Example 1 except that the following points were changed. The results are shown in Table 1.

-Conductive particles in protective layer The water-repellent treatment of the conductive particles was changed from the water-repellent treatment example 4 to the water-repellent treatment example 2. The ratio of the fluorine atom-containing silane coupling agent having the structure represented by the formula (SC-1) is 13% by mass with respect to the mass of the conductive particles before the water-repellent treatment, and the ratio of water is the ratio before the water-repellent treatment. It was 4 mass% with respect to the mass of electroconductive particle. Further, SnO ₂ particles doped with Sb ₂ O ₅ were exposed to an atmosphere of 80% humidity for 8 hours before the water repellent treatment to adjust the loss on drying to 4% by mass.

Example 12
In Reference Example 1, a sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as Reference Example 1 except that the following points were changed. The results are shown in Table 1.

-Conductive particles in the protective layer The water-repellent treatment of the conductive particles was changed from the water-repellent treatment example 4 to the water-repellent treatment example 3. The ratio of the fluorine atom-containing silane coupling agent having the structure represented by the formula (SC-1) is 13% by mass with respect to the mass of the conductive particles before the water-repellent treatment, and the ratio of water is the ratio before the water-repellent treatment. It was 4 mass% with respect to the mass of electroconductive particle. Further, SnO ₂ particles doped with Sb ₂ O ₅ were exposed to an atmosphere of 80% humidity for 8 hours before the water repellent treatment to adjust the loss on drying to 4% by mass.

(Comparative Example 1)
In Example 3, an electrophotographic photosensitive member and a sample for measuring volume resistivity of a protective layer were prepared and evaluated in the same manner as in Example 3 except that the drying loss of the conductive particles before water repellent treatment was 1% by mass. did. The results are shown in Table 1.

(Comparative Example 2)
In Example 11, the loss on drying of the conductive particles before water repellent treatment was 1% by mass, and the proportion of water used for the water repellent treatment of the conductive particles was based on the mass of the conductive particles before water repellent treatment. A sample for measuring an electrophotographic photoreceptor and a protective layer volume resistivity was prepared and evaluated in the same manner as in Example 11 except that the content was 12% by mass. The results are shown in Table 1.

(Comparative Example 3)
In Comparative Example 2, an electrophotographic photosensitive member and a protective layer volume resistivity measurement sample were prepared and evaluated in the same manner as in Comparative Example 2, except that the drying loss of the conductive particles before water repellent treatment was 8% by mass. did. The results are shown in Table 1.

As described above, according to the present invention, in an electrophotographic photosensitive member containing conductive particles whose surface layer has been subjected to a water repellent treatment using a water repellent treatment agent, environmental fluctuations in the volume resistivity of the surface layer are small, It is possible to maintain the volume resistivity of the protective layer accurately and appropriately in the environment, and there is no image defect such as blurring, blurring, unevenness, and whiteout, and the output image has high definition, dot reproducibility, and electrical external force. Further, it is possible to provide an electrophotographic photosensitive member that is compatible with durability against mechanical external force and a method for manufacturing the same .

  Further, according to the present invention, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member can be provided.

It is a figure which shows the example of the layer structure of the electrophotographic photoreceptor of this invention. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 102 Conductive layer 103 Intermediate layer 104 Photosensitive layer 1041 Charge generation layer 1042 Charge transport layer 105 Layer containing conductive particles subjected to water repellent treatment using water repellent treatment agent 105 'Charge transport material and water repellent treatment agent 1 containing electroconductive particles that have been subjected to water repellency treatment by using 1 electrophotographic photosensitive member 2 shaft 3 charging means 4 exposure light 5 developing means 6 transfer means 7 cleaning means 8 fixing means 9 process cartridge 10 guide means

Claims (15)

In an electrophotographic photosensitive member having a support and a photosensitive layer on the support, and the surface layer being a layer containing conductive particles,
When the conductive particles lose weight on drying (Md is the mass after drying the non-water-repellent conductive particles at 105 ° C. for 2 hours, and M is the mass before drying, [(M−Md) / M] × 100 and obtained by subjecting the non-water-repellent treated conductive particles having a drying loss [mass%] of 2 to 7 mass% to water-repellent treatment using a water-repellent treatment agent. An electrophotographic photosensitive member characterized by being water-repellent treated conductive particles. The electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a 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 according to claim 1 , a charging unit, an exposure unit, a developing unit, and a transfer unit. In a method for producing an electrophotographic photosensitive member having a support and a photosensitive layer on the support, and the surface layer being a layer containing conductive particles,
Loss on drying (calculated as [(M−Md) / M] × 100, where Md is the mass after drying the non-water-repellent conductive particles at 105 ° C. for 2 hours and M is the mass before drying) Water-repellent treatment using a water-repellent treatment agent to non-water-repellent conductive particles having a loss on drying [mass%] of 2 to 7 mass%. A water repellent treatment step for obtaining particles;
And a surface layer forming step of forming the surface layer using the water repellent conductive particles. A method for producing an electrophotographic photoreceptor, comprising: Prior to the water-repellent treatment step, the non-water-repellent conductive particles having a loss on drying of 2 to 7% by mass are obtained by exposing the non-water-repellent conductive particles to an atmosphere having a humidity of 60% RH or more. The method for producing an electrophotographic photosensitive member according to claim 4 , further comprising a step. 6. The electrophotographic photosensitive member according to claim 4 , wherein a mass of the water-repellent treatment agent used in the water-repellent treatment step is 8 to 30 mass% with respect to a mass of the non-water-repellent conductive particles. Method. The method for producing an electrophotographic photosensitive member according to any one of claims 4 to 6 , wherein the water repellent treatment in the water repellent treatment step is a water repellent treatment by a wet method. The method for producing an electrophotographic photosensitive member according to any one of claims 4 to 7 , wherein the conductive particles are metal particles or metal oxide particles. The method for producing an electrophotographic photosensitive member according to claim 8 , wherein the metal oxide particles are tin oxide particles. The method for producing an electrophotographic photosensitive member according to claim 8 , wherein the metal oxide particles are tin oxide particles doped with antimony oxide. The method for producing an electrophotographic photosensitive member according to claim 10 , wherein the antimony oxide is Sb ₂ O ₅ . The tin oxide, method for producing an electrophotographic photosensitive member according to any one of claims 9-11 is SnO _2. The method for producing an electrophotographic photosensitive member according to any one of claims 4 to 12 , wherein the water repellent treatment agent is a silane coupling agent. The method for producing an electrophotographic photosensitive member according to any one of claims 4 to 12 , wherein the water repellent agent is a siloxane compound or a fluorine atom-containing compound. The electron according to any one of claims 4 to 12 , wherein the water repellent treatment agent is at least one selected from the group consisting of a fluorine atom-containing silane coupling agent, a fluorine-modified silicone oil, and a fluorine atom-containing surfactant. A method for producing a photographic photoreceptor.

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