JP2005326783A - Electrophotographic photoreceptor, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of stably obtaining good image quality over a prolonged period of time. <P>SOLUTION: The electrophotographic photoreceptor 10 comprises a conductive substrate 1 and a photosensitive layer 6 disposed on the conductive substrate 1. The conductive substrate 1 comprises a first metal layer 1a and a second metal layer 1b disposed on a surface of the first metal layer 1a on a side closer to the photosensitive layer 6. The first metal layer 1a is based on a first metal showing a predetermined ionization tendency. The second metal layer 1b is based on a second metal showing a smaller ionization tendency than that of the first metal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge.

  The electrophotographic system uses an electrophotographic photosensitive member to perform image forming processes such as charging, exposure, development, and transfer, and because high-speed and high-quality printing is possible, copying machines, laser beam printers, etc. It is widely applied to image forming apparatuses.

As an electrophotographic photoreceptor used in such an image forming apparatus, in recent years, an organic photoreceptor in which a photosensitive layer is formed on a conductive substrate using a photoconductive organic material has become mainstream. In the case of organic photoreceptors, those in which an undercoat layer is provided between a conductive substrate and a photosensitive layer, and those in which a surface layer is provided as an outermost layer are known (see, for example, Patent Document 1). ).
JP-A-9-190004

  The electrophotographic photoreceptor is used repeatedly for a long time once it is mounted on the image forming apparatus. For this reason, there is a demand for extending the life of the electrophotographic photosensitive member.

  However, when the electrophotographic image forming process is repeated using the conventional electrophotographic photosensitive member, image defects such as ghost and fog are likely to occur.

  The present invention has been made in view of such circumstances, and an electrophotographic photosensitive member capable of stably obtaining good image quality over a long period of time, and an image forming apparatus and process using the electrophotographic photosensitive member. To provide a cartridge.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above-mentioned image defects are caused by the alteration of the surface of the conductive layer of the conductive substrate when the conventional electrophotographic photosensitive member is used for a long time. Has been found to occur.

  The alteration of the conductive substrate is caused by ionic components (hydroxide ions, halide ions, etc.) mixed in the photosensitive layer during production of the electrophotographic photosensitive member or moisture in the atmosphere due to ion conduction or the like on the photosensitive layer side of the conductive substrate. The present inventors speculate that this occurs due to accumulation on the surface and reaction (oxidation, corrosion, etc.) with the surface of the conductive substrate. Further, in the image forming process, light stress due to exposure and electrical stress due to inflow of electric charge are applied to the conductive substrate, and these stresses are considered to be factors that promote deterioration of the conductive substrate. Such alteration of the conductive substrate causes a change or non-uniformity in the characteristics (conductivity, etc.) of the substrate even if the degree of the change is relatively light.

  In conventional electrophotographic photoreceptors, the material of the conductive substrate is often selected in consideration of moldability and the like, and for example, aluminum is widely used. Aluminum is generally considered to be corrosion resistant. However, since the electroconductive substrate of the electrophotographic photosensitive member is used under a strong stress as described above and requires high surface characteristics, the corrosion resistance of the conventional aluminum substrate is not always sufficient. I can't say that.

  In order to solve the above problems, an electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the conductive material is a conductive substrate. A first metal layer mainly composed of a first metal having a predetermined ionization tendency, and the first metal provided on a surface of the first metal layer closer to the photosensitive layer; And a second metal layer mainly composed of a second metal exhibiting an ionization tendency smaller than the ionization tendency.

  According to the electrophotographic photosensitive member of the present invention, the conductive base having the first and second metal layers, the main components of which are the first and second metals whose ionization potential satisfies the above condition, is formed, and the second metal By disposing the layer closer to the photosensitive layer, sufficient resistance to ionic components and moisture is imparted. Therefore, even if light stress or electrical stress is applied between the conductive substrate and the photosensitive layer in the presence of an ionic component or moisture, the surface of the conductive substrate on the photosensitive layer side is sufficiently prevented from deteriorating and good. Image quality can be obtained stably over a long period of time.

  The second metal layer according to the present invention is distinguished from the undercoat layer provided between the conductive substrate and the photosensitive layer for the purpose of preventing the inflow of carriers from the conductive substrate to the photosensitive layer. It is. That is, the constituent material of the undercoat layer usually has a blocking property for carriers but does not have a blocking property for ionic components. Therefore, as a matter of course, even if an undercoat layer is provided on the first metal layer instead of the second metal layer, the above-described effect cannot be obtained.

  Moreover, in this invention, it is preferable that the 1st metal mentioned above is aluminum, and the 2nd metal mentioned above is a metal with a smaller ionization tendency than aluminum. Furthermore, the second metal is preferably a metal having a smaller ionization tendency than hydrogen, and is useful if it is at least one selected from gold, silver, copper, palladium, platinum, rhodium, and titanium.

  Thereby, since the corrosion resistance of the second metal layer is further improved, the corrosion of the conductive substrate is more reliably suppressed. Although it is conceivable that the conductive substrate is composed of only the second metal, not only the cost is increased, but, for example, if the conductive substrate is made only of gold, the mechanical strength is insufficient.

  In the present invention, the above-mentioned second metal layer is obtained by applying a dispersion liquid containing fine particles of the second metal having an average particle diameter of 1 to 100 nm on an object to be processed and heat-treating it. preferable. By using the metal fine particles in this way, it becomes possible to form a film at a temperature lower than the melting point inherent to the metal element constituting the metal fine particles, so that a uniform film can be obtained.

  In the present invention, it is preferable to further include an undercoat layer formed between the conductive substrate and the photosensitive layer. This makes it possible to prevent the inflow of charges from the conductive substrate to the photosensitive layer and to suppress fluctuations in the electric resistance value, so that long-term stabilization of good image quality can be realized more reliably. It is also possible to improve the adhesion between the conductive substrate and the photosensitive layer. In this case, the ionic component includes halogen ions, hydroxide ions, and the like contained in the binder resin constituting the undercoat layer.

  Furthermore, in the present invention, a layer containing at least one selected from a fluorine-based resin, a silicone-based resin, and a polyolefin-based resin provided on the surface of the above-described photosensitive layer far from the conductive substrate is further included. You may have. The photosensitive layer of the electrophotographic photoreceptor of the present invention preferably contains at least one selected from halogenated gallium phthalocyanine, halogenated tin phthalocyanine, hydroxygallium phthalocyanine, oxytitanium phthalocyanine, selenium alloy and zinc oxide.

  The image forming apparatus of the present invention includes the above-described electrophotographic photosensitive member of the present invention, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to expose the electrophotographic photosensitive member on the electrophotographic photosensitive member. An exposure device for forming an electrostatic latent image on the surface, a developing device for developing the electrostatic latent image to form a toner image on the electrophotographic photosensitive member, and the toner image on the electrophotographic photosensitive member being transferred. And a transfer device for transferring to a medium. Further, the process cartridge of the present invention comprises the above-described electrophotographic photosensitive member of the present invention, a charging device for charging the electrophotographic photosensitive member, and developing the electrostatic latent image to form a toner image on the electrophotographic photosensitive member. And a developing device to be formed, and at least one selected from a cleaning device that removes toner remaining on the electrophotographic photosensitive member after the transfer step.

  Since the image forming apparatus and the process cartridge of the present invention include the electrophotographic photosensitive member of the present invention, good image quality can be stably obtained over a long period of time. In recent years, an image forming process using a laser with an oscillation wavelength of about 380 to 450 nm has been studied for the purpose of improving the image quality. In this case, since the exposure spot is condensed to about 30 nm, easily influenced. On the other hand, the image forming apparatus of the present invention can realize long-term image quality stabilization by including the electrophotographic photosensitive member of the present invention, and thus is useful for such high-definition image formation.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member capable of stably obtaining good image quality over a long period of time. In addition, an image forming apparatus and a process cartridge using the electrophotographic photosensitive member can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Electrophotographic photoreceptor)
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. As shown in FIG. 1, the electrophotographic photoreceptor 10 includes a conductive substrate 1, an undercoat layer 3 formed on the conductive substrate 1, a photosensitive layer 6 formed on the undercoat layer 13, and a photosensitive layer. And a surface layer (protective layer) 9 formed on the layer 6. The electrophotographic photoreceptor 10 is a function-separated photoreceptor in which the photosensitive layer 6 is separated into a charge generation layer 5 and a charge transport layer 7. And the electroconductive base | substrate 1 in this embodiment has the 1st metal layer 1a and the 2nd metal layer 1b. The second metal layer 1b is formed on the first metal layer 1a.

Hereinafter, each component of the electrophotographic photoreceptor 10 will be described in detail.
First, the conductive substrate 1 will be described. As described above, the conductive substrate 1 has the first metal layer 1a and the second metal layer 1b. As the shape of the conductive substrate, a drum shape, a sheet shape, a plate shape, or the like is preferably used, but is not limited thereto.

  The first metal layer 1a is mainly composed of a metal such as aluminum, nickel, iron, and stainless steel. Further, anodizing treatment, boehmite treatment, honing treatment and the like may be performed for the purpose of preventing charge injection, improving adhesion, preventing interference fringes, and the like. The 2nd metal layer 1b has as a main component the metal which shows an ionization tendency smaller than the ionization tendency of a 1st metal. When the first metal is aluminum, the second metal is preferably a metal having a smaller ionization tendency than aluminum, and more preferably a metal having a smaller ionization tendency than hydrogen. Examples of the second metal include gold, silver, copper, palladium, platinum, rhodium, and titanium, and it is desirable that at least one of these metals is a main component.

  The content of the first metal is 95% by mass or more, preferably 98% by mass or more, more preferably 99% by mass or more, based on the total mass of the metal constituting the first metal layer. Note that the content of the second metal is the same as that of the first metal.

  As a method for forming the second metal layer 1b on the first metal layer 1a, a physical method such as sputtering or vacuum deposition, a chemical method such as plating, a second method having an average particle diameter of 1 to 100 nm is used. Examples thereof include a method (metal nanopaste method) in which a dispersion liquid (paste composition) in which metal fine particles containing metal as a main component are stably dispersed in a solvent is applied on the object to be treated by dipping or the like (heat treatment). Among these, sputtering and vacuum deposition are expensive because they require equipment for making a vacuum. A method such as plating tends to result in a non-uniform film depending on the material composition of the surface of the conductive substrate (for example, a component such as iron added to increase ductility). As described above, the physical method and the chemical method have the above-mentioned problems, but the metal nanopaste method is preferable in that a uniform film can be obtained by a simple method of coating and heating.

  This metal nanopaste method will be described. First, a dispersion is prepared by dispersing fine particles such as gold, silver and copper having an average particle diameter of 1 to 100 nm, preferably 2 to 80 nm in an organic solvent in the presence of an organic compound capable of coordinating with the fine particles. . Such a dispersion is a paste composition in which the surface of metal fine particles is coated with the organic compound described above and is stably dispersed in an organic solvent. Examples of organic compounds capable of coordinating with fine metal particles include amines such as hexylamine and dodecylamine, phenols such as phenol and catechol, alcohols such as hexanol and octanol, and thiols such as octanethiol and dodecanethiol. It is done. Examples of the organic solvent include tetrahydrofuran, toluene, xylene, terpineol, and mineral spirit. The dispersion contains 5 to 200 parts by mass, preferably 7 to 100 parts by mass of the organic compound, and 20 to 300 parts by mass, preferably 30 to 200 parts by mass of the organic solvent, with respect to 100 parts by mass of the metal fine particles. It is preferable to do.

  Next, a dispersion prepared to have a desired concentration is applied onto the object to be processed. The electrophotographic photoreceptor 10 shown in FIG. 1 has a structure in which the conductive substrate 1 is laminated with the first metal layer 1a and the second metal layer 1b as described above. Therefore, in this case, the first metal layer 1a is the object to be processed. As a coating method, a conventionally known method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used.

  Subsequently, the to-be-processed object apply | coated with the dispersion liquid is 100-400 degreeC, Preferably it heat-processes at 150-300 degreeC for 10 to 200 minutes, Preferably it is 20 to 90 minutes, 2nd on the 1st metal layer 1a. The metal layer 1b is formed. The film thickness of the second metal layer is 0.05 to 10 μm, preferably 0.1 to 7 μm.

  Next, the undercoat layer 3 will be described. The undercoat layer 3 prevents the injection of charges from the conductive substrate 1 to the photosensitive layer 6 when the photosensitive layer 3 is charged as described above, and the photosensitive layer 6 is integrally formed with the conductive substrate 1. It has a function as an adhesive layer for adhering and holding.

  Examples of materials used for forming the undercoat layer 3 include zirconium chelate compounds, zirconium alkoxide compounds, organic zirconium compounds such as zirconium coupling agents, titanium chelate compounds, titanium alkoxide compounds, organic titanium compounds such as titanate coupling agents, and aluminum. In addition to organoaluminum compounds such as chelate compounds and aluminum coupling agents, antimony alkoxide compounds, germanium alkoxide compounds, indium alkoxide compounds, indium chelate compounds, manganese alkoxide compounds, manganese chelate compounds, tin alkoxide compounds, tin chelate compounds, aluminum silicon alkoxides Compound, aluminum titanium alkoxide compound, aluminum zirconium alkoxy Organometallic compounds such as compounds. Among these, the use of an organic zirconium compound, an organic titanyl compound, or an organoaluminum compound is particularly preferred because a low residual potential and good electrophotographic characteristics can be obtained.

  Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ -Aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, β-3,4- It can be used by containing a silane coupling agent such as epoxycyclohexyltrimethoxysilane.

  Furthermore, conventionally, the undercoat layer 3 is formed by polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, polyimide, casein, gelatin. Polyethylene, polyester, phenol resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, polyacrylic acid and the like can also be used. These mixing ratios can be appropriately set as necessary.

  In the undercoat layer 3, an electron transport pigment can also be mixed / dispersed. Examples of the electron transporting pigment include perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, indigo pigments, quinacridone pigments, and the like described in JP-A-47-30330. And organic pigments such as bisazo pigments and phthalocyanine pigments having electron-withdrawing substituents such as nitroso groups and halogen atoms, and inorganic pigments such as zinc oxide and titanium oxide. Among these pigments, perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, zinc oxide and titanium oxide are preferably used because of their high electron mobility. In addition, the surface of these pigments may be surface-treated with the above-mentioned coupling agent or binder for the purpose of controlling dispersibility and charge transportability. When the amount of the electron transporting pigment is too large, the strength of the undercoat layer 3 is lowered and a coating film defect is generated, so that it is used at 95% by mass or less, preferably 90% by mass or less. As a mixing / dispersing method, a conventional method using a ball mill, a roll mill, a sand mill, an attritor, an ultrasonic wave, or the like is applied. Such mixing / dispersion is carried out in an organic solvent, but any organic solvent that dissolves a fixed metal compound or resin and does not cause gelation or aggregation when an electron transporting pigment is mixed / dispersed. Can be used. Examples of the organic solvent include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene. Usual organic solvents such as chloride, chloroform, chlorobenzene and toluene can be used alone or in admixture of two or more. The thickness of the undercoat layer 3 is generally 0.1 to 30 μm, preferably 0.2 to 25 μm. In addition, as a coating method for forming the undercoat layer 3, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. Can be used. The undercoat layer 3 can be obtained by drying after applying the coating solution. Usually, the drying is performed at a temperature at which the solvent can be evaporated to form a film. In particular, it is preferable to form the undercoat layer 3 because the substrate subjected to the acidic solution treatment and the boehmite treatment tends to have insufficient defect concealing power.

  Next, the charge generation layer 5 will be described. The charge generation layer 5 includes a charge generation material and a binder resin. As the charge generation material, all known materials such as azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, and phthalocyanine pigments can be used. Among these, metal and metal-free phthalocyanine pigments, selenium alloys and zinc oxide fine particles are preferable. Among these, when a semiconductor laser having an oscillation wavelength of 600 to 850 nm is used as an exposure light source, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, JP-A-5-98181. Chlorogallium phthalocyanine disclosed in JP-A-5-140472 and JP-A-5-140473, disclosed in JP-A-4-189873 and JP-A-5-43813. Titanyl phthalocyanine is particularly preferred. Further, when a semiconductor laser having an oscillation wavelength of 350 to 480 nm is used as an exposure light source, fine particles of trigonal selenium and zinc oxide are particularly preferable.

  The binder resin can be selected from a wide range of insulating resins. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Preferred binder resins include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used alone or in admixture of two or more.

  The mixing ratio (mass ratio) of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10. Further, as a method for dispersing them, a usual method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. In this case, it is necessary that the crystal form of the charge generating material does not change due to dispersion. In the present embodiment, the inventor has confirmed that the crystal form does not change before and after dispersion in any of the dispersion methods described above. Furthermore, it is useful that the particle size is 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less during the dispersion. Moreover, as solvents used for these dispersions, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, Usual organic solvents such as tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene can be used alone or in admixture of two or more. The film thickness of the charge generation layer 5 is generally 0.1 to 5 μm, preferably 0.2 to 2.0 μm. In addition, as a coating method for forming the charge generation layer 5, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. Can be used.

Next, the charge transport layer 7 will be described. The charge transport layer 7 is formed containing a charge transport material and a binder resin, or is formed containing a polymer charge transport material. Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds Electron transporting compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore transporting compounds. These charge transport materials can be used alone or in admixture of two or more, but are not limited thereto. From the viewpoint of mobility, a charge transport material having a structure represented by the following general formulas (1) to (3) is preferable.

上記（２）式中、Ｒ^１２、Ｒ^１３は同一でも異なってもよく、水素原子、ハロゲン原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基を示す。Ｒ^１４、Ｒ^１５、Ｒ^１６、Ｒ^１７は同一でも異なってもよく、水素原子、ハロゲン原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基、炭素数１〜２のアルキル基で置換されたアミノ基、置換若しくは未置換のアリール基、又は、−Ｃ(Ｒ^１８)＝Ｃ（Ｒ^１９）(Ｒ^２０)を示す。Ｒ^１８、Ｒ^１９、Ｒ^２０は同一でも異なってもよく、水素原子、置換若しくは未置換のアルキル基、又は、置換若しくは未置換のアリール基を示す。ｂ及びｃはそれぞれ０〜２の整数を示す。

In the above (1), R ¹¹ represents a hydrogen atom or a methyl group. A represents 1 or 2. Ar ¹ and Ar ² represent a substituted or unsubstituted aryl group, and as such a substituent, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or 1 to 1 carbon atoms And a substituted amino group substituted with 3 alkyl groups.

In the above formula (2), R ¹² and R ¹³ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ may be the same or different, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl having 1 to 2 carbon atoms. An amino group substituted with a group, a substituted or unsubstituted aryl group, or —C (R ¹⁸ ) ═C (R ¹⁹ ) (R ²⁰ ) is shown. R ¹⁸ , R ¹⁹ and R ²⁰ may be the same or different and each represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. b and c each represent an integer of 0-2.

In the above formula (3), R ²¹ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH—CH═C. (Ar) ₂ is shown. Ar represents a substituted or unsubstituted aryl group. R ²² and R ²³ may be the same or different, and are an amino group substituted with a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms. Or a substituted or unsubstituted aryl group.

  Further, the binder resin includes polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer. Polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polysilane Polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. These binder resins can be used alone or in admixture of two or more. The blending ratio (mass ratio) of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  A polymer charge transport material can also be used alone. As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane can be used. In particular, the polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 are particularly preferable because they have high charge transport properties. The polymer charge transport material can be used as the charge transport layer 7 by itself, but may be formed by mixing with the binder resin.

  The thickness of the charge transport layer is generally 5 to 50 μm, preferably 10 to 30 μm. As a coating method, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used. Furthermore, as a solvent used for forming the charge transport layer, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, methylene chloride, chloroform and ethylene chloride are used. Usual organic solvents such as halogenated aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran and ethyl ether can be used alone or in admixture of two or more.

Further, additives such as an antioxidant, a light stabilizer, and a heat stabilizer are added to the photosensitive layer 6 for the purpose of preventing deterioration of the photoreceptor due to ozone and oxidizing gas generated in the image forming apparatus or light and heat. Can be added. Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine. In addition, at least one kind of electron accepting substance can be contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of the electron acceptor that can be used for the electrophotographic photoreceptor 10 of the present embodiment include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquino. Dimethane, o-dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid, represented by the following general formula (4) A compound can be mentioned. Of these, benzene derivatives having an electron-withdrawing substituent such as fluorenone-based, quinone-based, Cl, CN, and NO ₂ are particularly preferable. When the charge transport layer is the outermost surface layer, an additive for an electrophotographic photoreceptor represented by the following general formula (4) can be added to this layer.

  Next, the surface layer 9 will be described. The surface layer 9 is a layer provided on the outermost part, and is configured, for example, by containing a conductive material in an appropriate binder resin. The surface layer 9 has a function of preventing chemical changes of the photosensitive layer 18 and the like during charging and increasing the mechanical strength of the photosensitive layer 18.

From such a viewpoint, a high-strength surface layer 9 having resistance to abrasion, scratches, and the like can be provided on the charge transport layer 7. Examples of the high-strength surface layer 9 include those obtained by dispersing conductive fine particles in a binder resin, those obtained by dispersing lubricating fine particles such as fluororesin and acrylic resin in a normal charge transport layer material, silicone, acrylic, etc. Hard coating agents and phenolic resin-based curing materials can be used. Among these, from the viewpoints of strength, electrical characteristics, image quality maintenance, and the like, those made of a siloxane resin having charge transporting properties and having a crosslinked structure are preferable. Among these, a compound having a structure represented by the following general formula (4) is particularly preferable because of excellent strength and stability.
G-D-F (4)

  F in the general formula (4) represents a charge transporting subunit, and is an organic group derived from a compound having photocarrier transport properties. Such compounds include triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, quinone compounds, fluorenone compounds, xanthone compounds, benzophenones. Compounds, cyanovinyl compounds, ethylene compounds, and the like.

  D in the above general formula (4) represents a flexible organic subunit. Such D has a role of directly binding F for imparting charge transporting properties to a three-dimensional inorganic glassy network. In addition, it has a function of imparting appropriate flexibility to the inorganic glassy network having brittleness while improving rigidity as a film.

  G in the general formula (4) represents an inorganic glassy network subgroup. As such G, a reactive silicon group is particularly preferably used. Such silicon groups can cause a cross-linking reaction with each other to form a three-dimensional Si—O—Si bond, that is, an inorganic glassy network.

In addition, the polymerizable compound used in combination with the compound represented by the general formula (4) may have a group capable of binding to a silanol group generated when the compound represented by the general formula (4) is hydrolyzed. There is no particular limitation. Examples of the group capable of binding to the compound represented by the general formula (4) include a group capable of binding to a silanol group generated when the compound represented by the general formula (4) is hydrolyzed. Specifically, groups (hereinafter, referred to as "substituted silicon group") represented by -SiR 21 ^_3-e Q _e, epoxy group, isocyanate group, carboxyl group, hydroxy group, refers to a halogen. Among these, the compound which a substituted silicon group, an epoxy group, and an isocyanate group have is preferable at the point which can obtain stronger mechanical strength. Furthermore, a compound having two or more of these groups in the molecule is preferable because the crosslinked structure of the cured film becomes three-dimensional and can have a stronger mechanical strength.

  For the purpose of adjusting the film formability and flexibility of the film, it may be used by mixing with other coupling agents, fluorine compounds, and fluorine polymers. As such a compound, for example, various silane coupling agents and commercially available silicone hard coat agents can be used.

  As silane coupling agents, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane Dimethyldimethoxysilane or the like can be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (above, manufactured by Shin-Etsu Silicone), AY42-440, AY42-441, AY49-208 (above, Toray Dow Corning) Etc.) can be used. Further, for imparting water repellency and the like, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (hepta) Fluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyl Fluorine-containing compounds such as triethoxysilane may be added. The silane coupling agent can be used in any amount, but the amount of the fluorine-containing compound used is desirably 0.25 or less by mass ratio with respect to the compound not containing fluorine. Beyond this, there may be a problem with the film formability of the crosslinked film.

  In order to improve the strength of the film, it is more preferable to use the above-mentioned compounds having two or more substituted silicon groups at the same time. These coating solutions are prepared in the absence of a solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane. Can be used. It is preferable to use a solvent having a boiling point of 100 ° C. or less. Although the usage-amount of a solvent can be set arbitrarily, since it will become easy to precipitate the compound shown by the said General formula (4) when there are too few, it is 0.5 ~ with respect to 1 mass part of compounds shown by the said General formula (4). It is used at 30 parts by weight, preferably 1-20 parts by weight. The reaction temperature and time vary depending on the type of raw material, but it is usually 0 to 100 ° C, preferably 10 to 70 ° C, and particularly preferably 150 to 50 ° C. Although there is no restriction | limiting in particular in reaction time, Since it will become easy to produce gelation when reaction time becomes long, it is preferable to carry out in 10 minutes-100 hours.

  Further, a curing catalyst may be added. Curing catalysts include proton acids such as hydrochloric acid, acetic acid, phosphoric acid and sulfuric acid, bases such as ammonia and triethylamine, organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate and stannous oxalate, tetra-n-butyl Examples thereof include organic titanium compounds such as titanate and tetraisopropyl titanate, organic aluminum compounds such as aluminum tributoxide and aluminum triacetylacetonate, iron salts of organic carboxylic acids, manganese salts, cobalt salts, zinc salts and zirconium salts. Among these, a metal compound is preferable in terms of storage stability, metal acetylacetonate and acetylacetate are more preferable, and aluminum triacetylacetonate is particularly preferable. Although the usage-amount of a curing catalyst can be set arbitrarily, 0.1-20 mass% is preferable with respect to the total mass of the compound which has a substituted silicon group from viewpoints, such as storage stability, an electrical property, and intensity | strength, 0.3- 10 mass% is more preferable. The curing temperature can be arbitrarily set, but is set to 60 ° C. or higher, more preferably 80 ° C. or higher in order to obtain a desired strength. Although hardening time can be arbitrarily set as needed, 10 minutes-5 hours are preferable. It is also effective to stabilize the characteristics after the curing reaction by maintaining a high humidity state. Furthermore, depending on the application, it can be hydrophobized by surface treatment with hexamethyldisilazane, trimethylchlorosilane, or the like.

  When the surface layer 9 is composed of a crosslinked cured film, it is preferable to add an antioxidant for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated in the charger. When the photoconductor 10 has a long life by increasing the mechanical strength of the surface of the photoconductor 10, the photoconductor 10 comes into contact with an oxidizing gas for a long time. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, more preferably 10% by mass or less.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2-hydro Shi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  Also, a resin that dissolves in alcohol can be added for the purpose of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral has been modified with formal or acetoacetal (for example, ESREC B, K, manufactured by Sekisui Chemical Co., Ltd.), polyamide resin, cellulose resin, phenol resin and the like. Among these, polyvinyl acetal resin is particularly preferable in terms of electrical characteristics. The molecular weight of the resin described above is preferably 2,000 to 100,000, more preferably 5,000 to 50,000. If the molecular weight is less than 2,000, the desired effect cannot be obtained. If the molecular weight is more than 100,000, the solubility is lowered and the addition amount is limited, or the film formation is poor at the time of coating. The amount of the resin added is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, and still more preferably 5 to 20% by mass. When the content is less than 1%, it is difficult to obtain a desired effect. When the content is more than 40% by mass, image blurring under high temperature and high humidity tends to occur.

  Further, various fine particles can be added in order to improve the contamination resistance adhesion and lubricity on the surface of the electrophotographic photoreceptor 10. These can be used alone or in admixture of two or more. An example of such fine particles is silicon-containing fine particles. Silicon-containing fine particles are fine particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone fine particles. As the colloidal silica, an acidic or alkaline aqueous dispersion having an average particle diameter of 1 to 100 nm, preferably 10 to 30 nm, or a dispersion dispersed in an organic solvent such as alcohol, ketone, or ester can be used. You may use what is. The solid content of colloidal silica in the outermost surface layer is not particularly limited, but is 0.1 to 50 with respect to the total solid content of the outermost surface layer in terms of film forming properties, electrical characteristics, and strength. % By mass, preferably 0.1 to 30% by mass.

  Examples of the silicone fine particles include silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles that are spherical and have an average particle diameter of 1 to 500 nm, preferably 10 to 100 nm, and commercially available ones can be used. . Silicone fine particles are small particles that are chemically inert and have excellent dispersibility in resins. Furthermore, since sufficient characteristics can be obtained even if the content of the silicone fine particles is small, the surface properties of the electrophotographic photosensitive member 10 can be improved without inhibiting the crosslinking reaction. In other words, the lubricity and water repellency of the surface of the electrophotographic photosensitive member 10 are improved while being uniformly incorporated into a strong cross-linked structure, and good wear resistance and contamination resistance adhesion are maintained over a long period of time. Can do. The content of the silicone fine particles in the outermost surface layer in the electrophotographic photoreceptor 10 of the present embodiment is 0.1 to 30% by mass, preferably 0.5 to 10% by mass with respect to the total solid content of the outermost surface layer. is there.

Other fine particles include fluorine-based fine particles such as tetrafluoroethylene, trifluoride ethylene, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Materials Forum Lecture Proceedings, p89. Fine particles comprising a resin obtained by copolymerizing the above fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO—TiO ₂ , ZnO— Examples thereof include semiconductive metal oxides such as TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO. For the same purpose, an oil such as silicone oil can be added. Examples of the silicone oil include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto. Reactive silicone oils such as modified polysiloxanes and phenol-modified polysiloxanes; cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane; 5-trimethyl-1,3,5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrapheny Cyclic methylphenylcyclosiloxanes such as cyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane; cyclic phenylcyclo such as hexaphenylcyclotrisiloxane Siloxanes; fluorine-containing cyclosiloxanes such as 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane; hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixture, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane And cyclic siloxanes such as vinyl group-containing cyclosiloxanes such as pentavinylpentamethylcyclopentasiloxane.

  A siloxane-based resin having a charge transporting property and having a cross-linked structure has excellent mechanical strength and sufficient photoelectric characteristics, and is therefore used as the charge transport layer 7 of the multilayer photoreceptor according to the present embodiment. You can also In that case, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used. However, when a desired film thickness cannot be obtained by a single application, the desired film thickness can be obtained by applying a plurality of times. When performing multiple times of repeated application, the heat treatment may be performed at each application, or may be performed after being applied multiple times.

  The compound represented by the general formula (4) is most preferably contained in the outermost surface layer 9 of these photoreceptors. Under the present circumstances, content of the compound shown by General formula (4) is 0.01-20 mass% with respect to the total mass of the material which forms the outermost surface layer 9, Preferably it is 0.02-15 mass%, More preferably Is 0.03 to 10% by mass. By setting it as this content rate, it comes to be excellent in film forming property, an electrical property, and lubricity. Further, the compound represented by the general formula (4) is preferably used by mixing with other charge transporting materials. Under the present circumstances, content of the compound shown by the said General formula (4) is 0.01-30 mass% with respect to all the charge transport materials contained in the outermost surface layer 9, Preferably it is 0.02-20 mass%, More preferably, it is 0.03-15 mass%. By setting it as this content rate, it comes to be excellent in an electrical property.

  Furthermore, the surface layer 9 of the electrophotographic photoreceptor 10, the blade member surface described later, and various members can be applied or immersed in an aqueous dispersion of a modified resin containing a fluorine-based resin as an essential component. This is preferable because torque can be further reduced and transfer efficiency can be improved. Examples of the fluororesin include tetrafluoroethylene homopolymers, copolymers of tetrafluoroethylene and olefins, fluorine-containing olefins, perfluoroolefins, fluoroalkyl vinyl ethers, vinylidene fluoride homopolymers, or vinylidene fluoride. Copolymers with olefins, fluorine-containing olefins, perfluoroolefins, fluoroalkyl vinyl ethers, homopolymers of chlorotrifluoroethylene, or copolymers of chlorotrifluoroethylene with olefins, fluorine-containing olefins, perfluoroolefins, fluoroalkyl vinyl ethers, etc. Etc. Among these, tetrafluoroethylene homopolymer or copolymer is particularly preferable. It is also preferable to use a mixture of a tetrafluoroethylene homopolymer and various copolymers in a mass ratio of 95: 5 to 10:90.

  The modified resin containing a fluorine-based resin as an essential component is used as an aqueous dispersion, and the aqueous dispersion may further contain a wax and / or silicone. It is preferable to contain wax and / or silicone because penetration of the fluorine-based resin into the blade can be promoted. Here, examples of the wax include paraffin wax, microcrystalline wax, and perotratam. Examples of silicone include silicone oil, silicone grease, oil compound, and silicone varnish. An aqueous dispersion of a modified resin containing a fluorine-based resin as an essential component includes a fluorine-based or other nonionic, cationic, anionic or amphoteric surfactant, a pH adjuster, a solvent, a polyhydric alcohol, if necessary. A softener, a viscosity modifier, a light stabilizer, an antioxidant and the like can also be mixed.

  The penetration layer can be formed by immersing the blade member in an aqueous dispersion of a modified resin containing a fluorine-based resin as an essential component. In order to promote penetration of the fluorine-based resin into the blade member. Further, it can be carried out under reduced pressure. The pressure at this time is 0.9 atm or less, preferably 0.8 atm or less, more preferably 0.7 atm or less. In addition, heating the aqueous dispersion to 40 ° C. or higher, preferably 50 ° C. or higher is effective in promoting penetration. Furthermore, it is effective to perform the treatment at 0.1 atm or higher, preferably 0.2 atm or higher, more preferably 0.3 atm or higher, and pressure reduction, pressurization, and heat treatment may be combined. Moreover, after making it adhere to a blade member by spraying or the apply | coating method, it heats to 40 degreeC or more, Preferably it is 50 degreeC or more, and you may form a osmosis | permeation layer. Further, after attaching an aqueous dispersion of a modified resin containing a fluorine-based resin as an essential component, wiping or washing can be performed before heat drying or after heat drying.

  The electrophotographic photoreceptor 10 is not limited to the above configuration. For example, the photosensitive layer 6 of the electrophotographic photoreceptor 10 may be a single-layer type photosensitive layer 6 as shown in FIG. This single-layer type photosensitive layer 6 is configured to contain the above-described charge generating substance and binder resin. As the binder resin, the same resins as those used for the charge generation layer 5 and the charge transport layer 7 described above can be used. The content of the charge generating substance in the single-layer type photosensitive layer 6 is about 10 to 85% by mass, preferably 20 to 50% by mass. A charge transport material or a polymer charge transport material may be added to the single-layer type photosensitive layer 6 for the purpose of improving the photoelectric characteristics. The addition amount is preferably 5 to 50% by mass. Moreover, you may add the compound shown by the said General formula (4). The solvent and coating method used for coating can be the same as described above. The film thickness is preferably about 5 to 50 μm, more preferably 10 to 440 μm.

  Further, in the electrophotographic photoreceptor 10, the stacking order of the charge generation layer 5 and the charge transport layer 7 may be reversed, and the undercoat layer 3 and / or the surface layer 9 may not exist. Further, if the second metal layer 1b is formed on the side closest to the photosensitive layer 6, the conductive substrate 1 has one or two or more between the first metal layer 1a and the second metal layer 1b. The metal layer may be further included.

(Image forming device)
FIG. 3 is a schematic configuration diagram showing the first embodiment of the image forming apparatus of the present invention. The image forming apparatus 100 shown in FIG. 3 includes the electrophotographic photoreceptor 10 described above. The electrophotographic photosensitive member 10 can be rotated in the direction of arrow A at a predetermined rotation speed by a driving device (not shown).

  A charger 14 for charging the outer peripheral surface of the electrophotographic photosensitive member 10 is provided substantially above the electrophotographic photosensitive member 10. As the charging method, a conventionally known corotron, a non-contact method using a scorotron, or the like can be preferably used. Furthermore, when the surface layer 9 has a high mechanical strength as described above, particularly excellent durability can be exhibited even when contact charging with a large stress on the electrophotographic photosensitive member 10 is used. An exposure device (for example, a laser optical system or an LED array) 16 is disposed substantially above the charger 14.

  A developing device 18 is disposed on the side of the electrophotographic photosensitive member 10. The developing device 18 includes a roller-shaped container that is rotatably arranged. Four containers are formed inside the container, and developing units 18Y, 18M, 18C, and 18K are provided in each container. Each of the developing units 18Y, 18M, 18C, and 18K includes a developing roller 20, and stores therein yellow (Y), magenta (M), cyan (C), and black (K) toners.

  Further, an endless intermediate transfer belt 24 is disposed substantially below the electrophotographic photoreceptor 10. The intermediate transfer belt 24 is wound around rollers 26, 28, and 30, and is disposed so that the outer peripheral surface is in contact with the outer peripheral surface of the electrophotographic photosensitive member 10. The rollers 26 to 30 are rotated by the driving force of a motor (not shown) being transmitted, and rotate the intermediate transfer belt 24 in the direction of arrow B.

  A transfer device 32 is disposed on the opposite side of the electrophotographic photosensitive member 10 across the intermediate transfer belt 24. The toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 10 is transferred to the image forming surface of the intermediate transfer belt 24 by the transfer device 32.

  A tray 34 is disposed below the intermediate transfer belt 24, and a large number of sheets P as recording materials are accommodated in the tray 34 in a stacked state. A take-out roller 36 is disposed obliquely above and to the left of the tray 34, and a roller pair 38 and a roller 40 are arranged in this order on the downstream side in the take-out direction of the paper P by the take-out roller 36. The uppermost recording paper in the stacked state is taken out of the tray 34 by the rotation of the take-out roller 36 and is conveyed by the roller pair 38 and the roller 40.

  A transfer device 42 is disposed on the opposite side of the roller 30 with the intermediate transfer belt 24 in between. The paper P conveyed by the roller pair 38 and the roller 40 is sent between the intermediate transfer belt 24 and the transfer device 42, and the toner image formed on the image forming surface of the intermediate transfer belt 24 is transferred by the transfer device 42. . A fixing device 44 having a pair of fixing rollers is arranged downstream of the transfer device 42 in the conveyance direction of the paper P. The paper P on which the toner image is transferred is transferred to the paper P by the fixing device 44. After being fused and fixed, the sheet is discharged out of the image forming apparatus 10 and placed on a discharge tray (not shown).

  Further, on the opposite side of the developing device 18 across the electrophotographic photosensitive member 10, there is a function of removing the outer peripheral surface of the electrophotographic photosensitive member 10 and a function of removing unnecessary toner remaining on the outer peripheral surface. -A cleaner 22 is arranged. When the toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 12 is transferred to the intermediate transfer belt 24, the region carrying the transferred toner image on the outer peripheral surface of the electrophotographic photosensitive member 12 is neutralized. -It is cleaned by the cleaner 22.

  In the image forming apparatus 100 shown in FIG. 3, a full color image is formed during the rotation process in which the electrophotographic photoreceptor 10 rotates four times. That is, while the electrophotographic photosensitive member 10 is rotated four times, the charger 14 continues to charge the outer peripheral surface of the electrophotographic photosensitive member 10, the static eliminator / cleaner 22 continues to discharge the outer peripheral surface, and the exposure device 16 should be formed. The electrophotographic photosensitive member 10 is rotated once by scanning the outer peripheral surface of the electrophotographic photosensitive member 10 with a laser beam modulated according to any of Y, M, C, and K image data representing a color image. Each time, the image data used for modulation of the laser beam is repeated while switching. Further, the developing device 18 operates the developing device corresponding to the outer peripheral surface in a state where any of the developing rollers 20 of the developing devices 18Y, 18M, 18C, and 18K corresponds to the outer peripheral surface of the electrophotographic photosensitive member 10. The electrostatic latent image formed on the outer peripheral surface of the electrophotographic photosensitive member 10 is developed to a specific color, and a toner image of the specific color is formed on the outer peripheral surface of the electrophotographic photosensitive member 10. Each time the body 10 rotates once, the process is repeated while rotating the container so that the developing unit used for developing the electrostatic latent image is switched.

  As a result, every time the electrophotographic photosensitive member 10 rotates, toner images of Y, M, C, and K are sequentially formed on the outer peripheral surface of the electrophotographic photosensitive member 10 so as to overlap each other. When the electrophotographic photosensitive member 10 is rotated four times, a full-color toner image is formed on the outer peripheral surface of the electrophotographic photosensitive member 12.

  FIG. 4 is a schematic configuration diagram showing a second embodiment of the image forming apparatus of the present invention. The image forming apparatus 200 is an intermediate transfer type image forming apparatus. In the housing 220, four electrophotographic photosensitive members 201a to 201d (for example, 201a is yellow, 201b is magenta, 201c is cyan, and 201d is black). Are formed in parallel with each other along the intermediate transfer belt 209. Here, the electrophotographic photoreceptors 201a to 201d mounted on the image forming apparatus 200 are the above-described electrophotographic photoreceptors of the present embodiment.

  Each of the electrophotographic photoreceptors 201a to 201d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 202a to 202d, the developing devices 204a to 204d, and the primary transfer roll 210a along the rotation direction. To 210d and cleaning blades 215a to 215d are arranged. In addition, the present inventor has obtained the knowledge that, when the cleaning blades 215a to 215d are set in the doctor direction, they are surprisingly effective in preventing the occurrence of ghosts. Each of the developing devices 204a to 204d can be supplied with toner of four colors, yellow, magenta, cyan, and black, stored in the toner cartridges 205a to 205d. Further, the primary transfer rolls 210a to 210d are in contact with the electrophotographic photosensitive members 201a to 201d via the intermediate transfer belt 209, respectively.

  Further, a laser light source (exposure device) 203 is disposed at a predetermined position in the housing 220. The laser light emitted from the laser light source 203 can be applied to the surfaces of the charged electrophotographic photosensitive members 201a to 201d. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 201a to 201d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 209 in an overlapping manner.

  The intermediate transfer belt 209 is supported with a predetermined tension by a drive roll 206, a backup roll 208, and a tension roll 207, and can rotate without causing deflection due to the rotation of these rolls. The secondary transfer roll 213 is disposed so as to contact the backup roll 208 via the intermediate transfer belt 209. The intermediate transfer belt 209 that has passed between the backup roll 208 and the secondary transfer roll 213 is cleaned by, for example, a cleaning blade 216 disposed in the vicinity of the drive roll 206 and then repeatedly used for the next image forming process. Is done.

  Further, a tray (transfer medium tray) 211 is provided at a predetermined position in the housing 220, and the transfer medium 230 such as paper in the tray 211 is transferred by the transfer roll 212 to the intermediate transfer belt 209 and the secondary transfer roll. Then, the sheet is sequentially transferred between the two fixing rolls 214 that are in contact with each other and between the two fixing rolls 214 and then discharged to the outside of the housing 220.

  In the above description, the case where the intermediate transfer belt 209 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 209 or a drum shape. Also good. When a belt-shaped configuration such as the intermediate transfer belt 209 is adopted as the intermediate transfer member, generally the thickness of the belt is preferably 50 to 500 μm, more preferably 60 to 150 μm. Note that the thickness of the belt can be appropriately selected according to the hardness of the material. When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  The transfer medium is not particularly limited as long as it is a medium that transfers a toner image formed on the electrophotographic photoreceptor 10. For example, when transferring directly from the electrophotographic photoreceptor 10 to paper or the like, paper or the like is a transfer medium, and when an intermediate transfer body is used, the intermediate transfer body is a transfer medium.

  In addition, the image forming apparatuses 100 and 200 preferably have a mechanism capable of supplying only the toner alone when the electrophotographic photosensitive member 10 is used for 200,000 cycles or more, 250,000 cycles, or 300,000 cycles or more. .

  Further, it is preferable to appropriately control the wear amount and surface roughness of the electrophotographic photoreceptor 10. As the means, the blade members 215a to 215d are brought into contact with the electrophotographic photosensitive member 10, the contact pressure and angle thereof are adjusted, the material of the protective layer 9 is made suitable, the control by the material of the blade members 215a to 215d, the polishing roll And adjustment by combined use with a brush member, strength control by the material of the protective layer 9 of the electrophotographic photoreceptor 10, and control by adding inorganic fine particles such as aluminum oxide, cerium oxide, and barium sulfate to the toner. By combining these controls, it is possible to control within an appropriate range.

  As an appropriate range of the wear rate, when the wear rate is 0.1 nm or less per 1,000 revolutions, contaminants on the surface of the electrophotographic photosensitive member 10 cannot be sufficiently removed, so that an image flow is likely to occur particularly under high temperature and high humidity. . Further, since the wear is large at 100 nm or more, it is difficult to extend the life. Further, if the surface roughness Rz exceeds 2 μm, the toner slips through and causes image quality defects. Therefore, the wear rate is preferably 0.1 to 80 nm per 1,000 revolutions, and the surface roughness Rz is preferably 2 μm or less.

  Further, the toner used in the exemplary embodiment is not particularly limited by the manufacturing method. Examples of the toner production method include a kneading and pulverizing method in which a binder resin, a colorant, a release agent, and a charge control agent as necessary are kneaded, pulverized, and classified. To change the shape by mechanical impact force or thermal energy, emulsion polymerization of a polymerizable monomer of the binder resin, and the formed dispersion, colorant, release agent, and charge control agent as required The emulsion polymerization aggregation method to obtain toner particles by mixing and agglomerating and heat-fusing with a dispersion liquid, a polymerizable monomer and a colorant, a release agent, and a charge control if necessary Suspension polymerization method in which a solution such as an agent is suspended in an aqueous solvent for polymerization, a binder resin and a colorant, a release agent, and if necessary, a solution such as a charge control agent is suspended in an aqueous solvent for granulation The dissolution suspension method can be used.

  In addition, a known method such as a method in which the toner obtained by the above production method is used as a core, and agglomerated particles are further adhered and heat-fused to have a core-shell structure can be used. Furthermore, from the viewpoint of shape control and particle size distribution control, a suspension polymerization method, an emulsion polymerization aggregation method and a dissolution suspension method which are produced with an aqueous solvent are preferable, and an emulsion polymerization aggregation method is particularly preferable. The toner base material includes a binder resin, a colorant, and a release agent. If necessary, silica or a charge control agent may be used. A toner base material having an average particle diameter of 2 to 12 μm, preferably 3 to 9 μm can be used. Further, by using a toner having an average shape index (ML2 / A) of 100 to 150, an image with high development, transferability and high image quality can be obtained.

(Process cartridge)
Next, a process cartridge equipped with the electrophotographic photosensitive member of the present invention will be described. FIG. 5 is a schematic diagram showing a basic configuration of a preferred embodiment of the process cartridge of the present invention.
In the process cartridge 300, the above-described electrophotographic photoreceptor 10, the exposure device 310, the developing device 311, the cleaning device 313, and the charging device 318 are mounted in a case 320 and combined and integrated using a rail 316. The process cartridge 300 is detachable from an image forming apparatus main body including a transfer device 312, a fixing device 315, and other components (not shown), and constitutes the image forming apparatus together with the image forming apparatus main body. To do.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

(Example 1)
Dispersion containing ultrafine silver particles (trade name: Independently dispersed ultrafine nano-metal ink, average particle diameter of silver fine particles 7 nm, manufactured by Vacuum Metallurgy Co., Ltd.) on a pipe of 84 mm diameter made of JIS A 3003 standard aluminum alloy ) Was applied by dip coating, followed by heat treatment at 200 ° C. for 1 hour to form a silver thin film having a thickness of about 2 μm. The specific resistance of the obtained conductive substrate was 8 × 10 ⁻⁷ Ω · cm.

Next, 100 parts by mass of zinc oxide (SMZ-017N, manufactured by Teika) and 500 parts by mass of toluene were mixed with stirring, 2 parts by mass of a silane coupling agent (A1100, manufactured by Nihon Unicar Company) was added, and the mixture was stirred for 5 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 2 hours. As a result of analyzing the surface-treated zinc oxide by fluorescent X-ray, the Si element strength was 1.8 × 10 ⁻⁴ of the zinc element strength. 35 parts by mass of this surface-treated zinc oxide, 15 parts by mass of blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane) as a curing agent, and 6 parts by mass of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) And 44 parts by mass of methyl ethyl ketone were mixed, and a dispersion was obtained by performing dispersion treatment for 2 hours with a sand mill using glass beads of 1 mmφ. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate as a catalyst and 17 parts by mass of Tospearl 130 (manufactured by GE Toshiba Silicone) were added to obtain an undercoat layer coating solution. This coating solution was applied on the base on which the above-described silver thin film was formed by a dip coating method, and was dried and cured at 160 ° C. for 100 minutes to form an undercoat layer having a thickness of 20 μm.

  Next, on this subbing layer, the Bragg angles (2θ ± 0.2 °) in the X-ray diffraction spectrum have strong diffraction peaks at 7.4 °, 16.6 °, 25.5 ° and 28.3 °. 1 part by mass of chlorogallium phthalocyanine was mixed with 1 part by mass of polyvinyl butyral (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate. After being dispersed with a glass shaker for 1 hour by a glass shaker, the resulting coating solution is dip-coated on the above-described undercoat layer and dried by heating at 100 ° C. for 10 minutes to generate a charge of about 0.15 μm. A layer was formed.

2 parts by mass of a benzidine compound represented by the following formula (5), 0.1 part by mass of 2,6-bis-t-butyl-4-hydroxytoluene, and a polymer compound (viscosity represented by the following formula (6)) Charge generation as described above for a coating solution in which 3 parts by mass of an average molecular weight of 39,000) is dissolved in 20 parts by mass of chlorobenzene and then 0.3 parts by mass of polytetrafluoroethane fine particles (Lublon L-2, manufactured by Daikin Industries) is dispersed. The layer was applied by dip coating, and heated at 110 ° C. for 40 minutes to form a charge transport layer having a thickness of 20 μm. The electrophotographic photoreceptor thus obtained is referred to as “photoreceptor 1”.

(Evaluation of electrophotographic characteristics)
The obtained photoreceptor 1 is equipped with a laser having an oscillation wavelength of 780 nm as an exposure light source, and a full color laser printer (product name: DocuCentre Color 500, manufactured by Fuji Xerox Co., Ltd.) having the same configuration as the image forming apparatus shown in FIG. Installed. Next, a continuous print test of 20,000 sheets is performed in an environment of high temperature and high humidity (30 ° C., 80% RH), and a continuous print test of 20,000 sheets is performed in an environment of low temperature and low humidity (10 ° C., 20% RH). The electrophotographic characteristics after the test were evaluated for ghosting, image quality, cleaning properties, transfer properties, and toner adhesion prevention properties. The evaluation results are shown in Table 1.

  For the occurrence of ghost, a chart having a letter G and a solid black portion was printed, and the appearance of the letter G was visually judged on the solid black portion. In the column of “Ghost generation” in Table 1, “◯” means “good” to “small”, “Δ” means that the letter “G” is slightly noticeable, and “x” means that the letter “G” can be clearly confirmed.

  The image quality was judged visually. In the column of “image quality” in Table 1, “◯” indicates that there is no image quality defect, “Δ” indicates partial (about 30% or less of the total) fogging, and “×” indicates fogging on the entire surface.

  Further, the cleaning property was visually determined. In the column of “Cleaning property” in Table 1, “◯” means “good”, “Δ” means that there is an image quality defect such as a streak partially (less than about 10% of the total), and “x” means that there is a wide image quality defect.

  Transferability was determined by peeling off the transfer residual toner on the surface of the photoreceptor with an adhesive tape and measuring the weight. In the column of “transferability” in Table 1, “◯” means transfer efficiency of 90% or more, “Δ” means transfer efficiency of 85 to 90%, and “x” means transfer efficiency of less than 85%.

  The toner adhesion preventing property was judged visually. In the column of “Toner adhesion prevention” in Table 1, “◯” means no toner adhesion, “Δ” means partial (about 30% or less of the total) toner adhesion, and “x” means toner adhesion.

(Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that Lubron L-2 was not used in forming the charge transport layer. Using the obtained electrophotographic photoreceptor (photoreceptor 2), an image forming apparatus was produced in the same manner as in Example 1, and the electrophotographic characteristics were evaluated. The evaluation results are shown in Table 1.

(Example 3)
Gold ultrafine particle dispersion (trade name NPG-J, Harima Kasei Co., Ltd.) is applied on a pipe of 84 mm diameter made of JIS A 3003 standard aluminum alloy, and heated at 220 ° C. for 1 hour. A gold thin film having a thickness of about 3 μm was formed by processing. The specific resistance of the obtained conductive substrate was 1 × 10 ⁻⁷ Ω · cm. A charge generation layer and a charge transport layer were formed on this substrate by the same method as in Example 2.

  Next, 2 parts by mass of a compound represented by the following formula (7) was added to 2 parts by mass of methyltrimethoxysilane, 0.5 parts by mass of tetramethoxysilane, 0.3 parts by mass of colloidal silica, 5 parts by mass of isopropyl alcohol, and tetrahydrofuran 3 It melt | dissolved in 0.3 mass part of distilled water and 0.3 mass part of distilled water, 0.5 mass part of ion exchange resin (Amberlyst 15E) was added, and it hydrolyzed for 24 hours by stirring at room temperature.

In the filtrate obtained by filtering and separating the ion exchange resin from the hydrolysis solution, 0.1 part by mass of aluminum trisacetylacetonate (Al (aqaq) ₃ ) and 3,5-di-t-butyl-4-hydroxytoluene (BHT) After adding 0.5 part by mass, the obtained coating liquid was applied on the above-described charge transport layer by a ring-type dip coating method and air-dried at room temperature for 30 minutes, and then cured by heat treatment at 170 ° C. for 1 hour, A surface layer having a thickness of about 3 μm was formed. Using the obtained electrophotographic photoreceptor (photoreceptor 3), an image forming apparatus was produced in the same manner as in Example 1, and the electrophotographic characteristics were evaluated. The evaluation results are shown in Table 1.

Example 4
In the same manner as in Example 3, except that a compound represented by the following formula (8) was used instead of the compound represented by the above formula (7) as a material used for forming the surface layer, The body was made. Using the obtained electrophotographic photoreceptor (photoreceptor 4), an image forming apparatus was produced in the same manner as in Example 1, and the electrophotographic characteristics were evaluated. The evaluation results are shown in Table 1.

(Examples 5 to 8)
An image forming apparatus is manufactured by the same method as in Examples 1 to 4 except that a laser with an oscillation wavelength of 405 nm is used as an exposure light source instead of a laser with an oscillation wavelength of 780 nm and the print speed is set to 1/2. A 100-sheet print test was performed, and only the initial image quality was evaluated according to the same criteria as in Example 1. The evaluation results are shown in Table 1.

(Comparative Examples 1-4)
An electrophotographic photosensitive member was produced in the same manner as in Examples 1 to 4, except that no metal thin film was formed on the pipe. Using the obtained electrophotographic photosensitive member (photosensitive members 5 to 8), an image forming apparatus was produced in the same manner as in Example 1, and the electrophotographic characteristics were evaluated. The evaluation results are shown in Table 1.

(Comparative Examples 5 to 8)
An image forming apparatus was produced by the same method as in Examples 5 to 8 except that the electrophotographic photoreceptors (Photoreceptors 5 to 8) obtained in Comparative Examples 1 to 4 were used, and the initial image quality was evaluated. The evaluation results are shown in Table 1.

1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. 1 is a schematic configuration diagram illustrating a preferred embodiment of an image forming apparatus of the present invention. 1 is a schematic configuration diagram illustrating a preferred embodiment of an image forming apparatus of the present invention. 1 is a schematic configuration diagram showing a preferred embodiment of a process cartridge of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductive base | substrate, 1a ... 1st metal layer, 1b ... 2nd metal layer, 3 ... Undercoat layer, 5 ... Charge generation layer, 7 ... Charge transport layer, 9 ... Surface layer, 10 ... Electrophotographic photosensitive body.

Claims (10)

An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer provided on the conductive substrate,
The conductive substrate is
A first metal layer mainly composed of a first metal exhibiting a predetermined ionization tendency;
A second metal layer comprising a second metal as a main component, which is provided on a surface of the first metal layer closer to the photosensitive layer and exhibits an ionization tendency smaller than the ionization tendency of the first metal. When,
An electrophotographic photosensitive member comprising:   2. The electrophotographic photoreceptor according to claim 1, wherein the first metal is aluminum and the second metal is a metal having a smaller ionization tendency than aluminum.   The electrophotographic photosensitive member according to claim 1, wherein the second metal is a metal having a smaller ionization tendency than hydrogen.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the second metal is at least one selected from gold, silver, copper, palladium, platinum, rhodium, and titanium. body.   The second metal layer is obtained by applying a dispersion liquid containing fine particles of the second metal having an average particle diameter of 1 to 100 nm on an object to be processed, and performing a heat treatment. Item 5. The electrophotographic photosensitive member according to any one of Items 1 to 4.   The electrophotographic photosensitive member according to claim 1, further comprising an undercoat layer provided between the conductive substrate and the photosensitive layer.   The layer further comprising at least one selected from a fluorine-based resin, a silicone-based resin, and a polyolefin-based resin, which is provided on a surface of the photosensitive layer far from the conductive substrate. The electrophotographic photosensitive member according to any one of 1 to 6.   The photosensitive layer contains at least one selected from halogenated gallium phthalocyanine, halogenated tin phthalocyanine, hydroxygallium phthalocyanine, oxytitanium phthalocyanine, selenium alloy and zinc oxide. The electrophotographic photosensitive member according to claim 1. The electrophotographic photosensitive member according to any one of claims 1 to 8,
A charging device for charging the electrophotographic photosensitive member;
An exposure apparatus that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image on the electrophotographic photosensitive member;
A developing device for developing the electrostatic latent image to form a toner image on the electrophotographic photosensitive member;
A transfer device for transferring the toner image on the electrophotographic photosensitive member to a transfer medium;
An image forming apparatus comprising: The electrophotographic photosensitive member according to any one of claims 1 to 8,
A charging device for charging the electrophotographic photosensitive member, a developing device for developing the electrostatic latent image to form a toner image on the electrophotographic photosensitive member, and removing toner remaining on the electrophotographic photosensitive member after the transfer process At least one selected from cleaning devices to perform,
A process cartridge comprising:

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