JP2005115098A - Electrophotographic photoreceptor, electrophotographic apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which has excellent durability, toner release property and cleanability and can sufficiently suppress the rise of a residual potential due to repeated use. <P>SOLUTION: An electrophotographic photoreceptor 1 has a conductive support 2 and a photosensitive layer 3 arranged on the conductive support 2. The photosensitive layer 3 contains one or ≥2 charge generating materials, one or ≥2 charge transfer materials, fluorine-base resin particles and fluorine-base graft polymer and is so constituted that the mass ratio X of the charge transfer material having the ionization potential smaller than that of the charge generating material having the smallest ionization potential among the charge generating materials to the total amount of the charge transfer materials and the mass ratio Y of the fluorine-base graft polymer to the fluorine-base resin particles satisfy the conditions expressed by the following equation (1), 0.5≤Y≤(0.02×X)+1.5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  In recent years, electrophotographic photoreceptors using organic photoconductive materials, so-called organic photoreceptors, are becoming mainstream photoreceptors because they are inexpensive and have excellent advantages in terms of manufacturability and disposal.

  However, organic photoreceptors are generally inferior in mechanical strength to inorganic photoreceptors and have a relatively short life due to abrasion and abrasion due to mechanical external forces such as cleaning blades, developing brushes, and paper. Further, in the system using the contact charging method that has been used in recent years from the viewpoint of ecology, the wear of the photosensitive member is greatly increased as compared with the charging method using the corotron. Therefore, a photoreceptor having sufficient durability is desired.

  On the other hand, in the electrophotographic apparatus, it is necessary to discard the residual toner generated at the time of transfer, and it is important to reduce the residual toner amount as much as possible in order to reduce the amount of toner to be discarded. Also, from the viewpoint of not generating waste toner, a so-called cleaner-less method has been proposed in which residual toner is collected in the developing device at the same time as development without providing a cleaning device.

  However, when the transfer efficiency is insufficient in the cleanerless system, a positive ghost in which the toner remaining on the photoconductor is printed out or a negative ghost due to the light shielding effect of the toner remaining on the photoconductor occurs. Therefore, increasing the toner transfer efficiency is important both in the system using the conventional cleaning device and the cleanerless system. In order to increase the toner transfer efficiency, it is important to efficiently transfer the toner particles adhering to the photoconductor. For this reason, a photoconductor with high toner releasability is desired.

In order to satisfy the characteristics required for such a photoreceptor, for example, Patent Document 1 proposes to use a fluorine resin particle and a fluorine graft polymer together in an electrophotographic photoreceptor.
JP-A-63-221355

  However, when a fluorine-based graft polymer is used together to improve the dispersibility of the fluorine-based resin particles, the residual potential increases due to repeated use over a long period of time, and the electrophotographic characteristics often deteriorate. Therefore, it is very difficult to achieve both sufficient durability and stable electrophotographic characteristics, and there is room for further improvement in the electrophotographic photosensitive member.

  The present invention has been made in view of the above-described problems of the prior art, and is excellent in durability, toner releasability, and cleanability, and can sufficiently suppress an increase in residual potential due to repeated use. An object is to provide an electrophotographic apparatus and a process cartridge.

  As a result of intensive studies to achieve the above object, the present inventors first obtained the following knowledge regarding the use of a fluorine-based graft polymer. That is, in order to improve the dispersibility of the fluorine-based resin particles, it is necessary to add a predetermined amount of the fluorine-based graft polymer, but if the amount of the fluorine-based graft polymer added is too large, the electrophotographic characteristics often deteriorate. Moreover, it is difficult to obtain desired electrophotographic characteristics only by adjusting the addition amount of the fluorine-based graft polymer.

  Next, the present inventors tried to improve electrophotographic characteristics by paying attention to the quantitative ratio between the fluorine-based resin particles and the fluorine-based graft polymer. Further, the contents of the charge generation material and the charge transport material contained in the photosensitive layer were also examined. However, sufficient electrophotographic characteristics could not be obtained simply by adjusting the contents of these components.

  Therefore, the present inventors have further studied in consideration of the influence of the ionization potential of the charge generation material and the charge transport material contained in the photosensitive layer. As a result, the present inventors have found that the above problems can be solved when the constituent components of the photosensitive layer satisfy specific conditions, and have completed the present invention.

That is, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having a conductive support and a photosensitive layer disposed on the conductive support, wherein the photosensitive layer is one or two. More than one type of charge generating material, one or more types of charge transporting material, fluorine resin particles, and fluorine type graft polymer, and having a minimum ionization potential among the above charge generating materials The mass ratio X of the charge transport material having a small ionization potential to the total amount of the charge transport material and the mass ratio Y of the fluorine-based graft polymer to the fluorine-based resin particles satisfy the condition represented by the following formula (1). It is characterized by that.
0.5 ≦ Y ≦ (0.02 × X) +1.5 (1)

  According to the electrophotographic photoreceptor of the present invention, each component contained in the photosensitive layer satisfies the condition represented by the above formula (1), so that an increase in residual potential due to repeated use over a long period can be suppressed, and wear and The durability against scratches is improved, and the releasability and cleaning properties for toner are also improved. As a result, it is possible to suppress the sensitivity of the photoreceptor from being reduced and the image density from being lowered, or the charging potential from being lowered to cause the image to be fogged. It is also possible to suppress a phenomenon called toner filming that occurs when some toner remains during transfer and image defects occur or toner components or paper components adhere to the photoreceptor. It becomes.

  In the electrophotographic photoreceptor of the present invention, the charge transportability and durability of the photosensitive layer are particularly excellent when the content of each component contained in the photosensitive layer satisfies the condition represented by the above formula (1). Therefore, the present inventors infer that the distribution state of each component in the photosensitive layer is optimized.

  The electrophotographic photoreceptor of the present invention preferably contains a charge transport material having an ionization potential smaller than that of the charge generation material having the minimum ionization potential in the photosensitive layer.

  The electrophotographic apparatus of the present invention includes an electrophotographic photosensitive member of the present invention, a charging device for charging the electrophotographic photosensitive member, and an exposure for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. And a developing device that forms a toner image by developing the electrostatic latent image, and a transfer device that transfers the toner image to a transfer medium.

  The process cartridge of the present invention includes the electrophotographic photosensitive member of the present invention, a charging device for charging the electrophotographic photosensitive member, an exposure device for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, And at least one selected from cleaning devices for cleaning an electrophotographic photosensitive member.

  According to the present invention, an electrophotographic photosensitive member that is excellent in durability, toner releasability, and cleaning properties, and that can sufficiently suppress an increase in residual potential due to repeated use, and an electron that can obtain good image quality over a long period of time. A photographic apparatus and a process cartridge are provided.

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

(Electrophotographic photoreceptor)
The electrophotographic photosensitive member of the present invention includes a conductive support and a photosensitive layer disposed on the conductive support. The photosensitive layer contains at least one or more charge generation materials, one or more charge transport materials, fluorine resin particles, and a fluorine graft polymer. The electrophotographic photoreceptor of the present invention includes a mass ratio X of the charge transport material having an ionization potential smaller than that of the charge generation material having a minimum ionization potential to the total amount of the charge transport material, and the fluorine-based material. The mass ratio Y of the graft polymer to the fluororesin particles satisfies the condition represented by the following formula (1).
0.5 ≦ Y ≦ (0.02 × X) +1.5 (1)

Here, the said mass ratio X (mass%) is shown by following formula (2).
X = (S _n / S _m ) × 100 (2)
[In the above formula (2), S _n represents the charge transporting material having an ionization potential lower than those with the lowest ionization potential of the charge generating material, S _m denotes the total amount of the charge transport material. ]

In the above formula (2), X = 0 when there is no charge transport material having an ionization potential smaller than that of the charge generation material having the minimum ionization potential. Further, when there is one kind of charge transport material having an ionization potential smaller than that having the minimum ionization potential among the charge generation materials, the content of one kind is _Sn , and If the charge-transporting material having an ionization potential lower than those with out lowest ionization potential is 2 or more, the total amount of the two or more content is S _n.

Moreover, the said mass ratio Y is shown by following formula (3).
Y = (a / b) × 100 (3)
[In the above formula (3), a represents the content of fluorine-based graft polymer, and b represents the content of fluorine-based resin particles. ]

  The electrophotographic photosensitive member of the present invention preferably contains a charge transport material having an ionization potential smaller than that of the charge generation material having the minimum ionization potential. In this case, X> 0.

  In the electrophotographic photoreceptor of the present invention, the photosensitive layer may have a single-layer structure or a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. In the case of a laminated structure, the charge generation layer and the charge transport layer may be stacked in any order.

  Hereinafter, preferred embodiments of the electrophotographic photoreceptor will be described in detail. 1 to 3 are schematic cross-sectional views each showing a preferred embodiment of an electrophotographic photosensitive member. The electrophotographic photosensitive member shown in FIGS. 1 and 3 includes a photosensitive layer 3 whose functions are separated into a layer containing a charge generation material (charge generation layer 5) and a layer containing a charge transport material (charge transport layer 6). It is to be prepared. In FIG. 2, the charge generation material and the charge transport material are contained in the same layer (single-layer type photosensitive layer 8).

  The electrophotographic photoreceptor 1 shown in FIG. 1 has a structure in which an undercoat layer 4, a charge generation layer 5, and a charge transport layer 6 are sequentially laminated on a conductive support 2. Further, the electrophotographic photoreceptor 1 shown in FIG. 2 has a structure in which an undercoat layer 4 and a single-layer type photosensitive layer 8 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 1 shown in FIG. 3 has a structure in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6, and a protective layer 7 are sequentially laminated on a conductive support 2.

  Next, with reference to FIG. 1, each element of the electrophotographic photoreceptor 1 will be described in detail.

  As the conductive support 2, a conventional one that has been conventionally used can be used. As the conductive support 2, for example, metals such as aluminum, nickel, chromium, and stainless steel; thin films such as aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, and ITO are provided. Plastic film etc .; Paper or plastic film etc. which apply | coated or impregnated the electroconductivity imparting agent can be used. The shape of the conductive support is not limited to a drum shape, and may be a sheet shape or a plate shape.

  In the case where the conductive support 2 is a metal pipe, the surface may remain as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing is performed in advance. It may be broken.

  The photosensitive layer 3 is disposed on the conductive support 2, and the undercoat layer 4 is disposed on the conductive support 2 in the photosensitive layer 3.

  The undercoat layer 4 includes a conductive substance and a binder resin.

  Examples of the conductive substance include metal powders such as aluminum, copper, nickel, and silver, conductive metal oxides such as antimony oxide, indium oxide, tin oxide, and zinc oxide, carbon fiber, carbon black, and graphite powder. Is mentioned.

As the conductive metal oxide, fine particles having a particle size of 0.5 μm or less are preferably used. Here, the particle size means an average primary particle size. The undercoat layer 4 needs to have an appropriate resistance for obtaining leak resistance. Therefore, the metal oxide fine particle needs a powder resistance of about 10 ² to 10 ¹¹ Ω · cm. Among these, it is preferable to use metal oxide fine particles such as tin oxide, titanium oxide, and zinc oxide having a resistance value in the above range. When the resistance value of the metal oxide fine particles is less than the above lower limit value, sufficient leak resistance tends to be difficult to be obtained. On the other hand, when the resistance value exceeds the above upper limit value, the residual potential tends to increase.

  Moreover, 2 or more types of metal oxide fine particles can be mixed and used. Furthermore, the powder resistance can be controlled by subjecting the metal oxide fine particles to a surface treatment with a coupling agent.

  Any coupling agent can be used as long as it can obtain desired photoreceptor characteristics. Specific coupling agents include, for example, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycid. Xylpropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (amino Examples include silane coupling agents such as ethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. It is not limited to. Moreover, these coupling agents can also be used individually by 1 type or in mixture of 2 or more types.

  As the surface treatment method, any known method can be used, but a dry method or a wet method can be used. When surface treatment is performed by a dry method, a metal oxide fine particle is agitated with a mixer having a large shearing force or the like, or a coupling agent dissolved in an organic solvent or water is added to dry air or nitrogen gas. It is processed uniformly by spraying together. The addition or spraying is preferably performed at a temperature of 50 ° C. or higher. After addition or spraying, baking can be performed at 100 ° C. or higher.

  Baking can be carried out in an arbitrary range as long as the temperature and the time at which desired electrophotographic characteristics are obtained. In the dry method, the surface adsorbed water can be removed by heating and drying the metal oxide fine particles before the surface treatment with the coupling agent of the metal oxide fine particles. By removing the surface adsorbed water before the treatment, the coupling agent can be uniformly adsorbed on the surface of the metal oxide fine particles.

  As a wet method, first, metal oxide fine particles are dispersed in a solvent by using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill or the like. Next, after the coupling agent solution is added and stirred or dispersed, the solvent is removed to uniformly treat. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and the time at which desired electrophotographic characteristics are obtained. Even in the wet method, the surface adsorbed water can be removed before the surface treatment with the coupling agent of the metal oxide fine particles. As this surface adsorbed water removal method, in addition to heat drying similar to the dry method, a method of removing while stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropy with the solvent, and the like can be carried out.

In addition, it is essential that the amount of the surface treatment agent with respect to the metal oxide fine particles is an amount capable of obtaining desired electrophotographic characteristics. The electrophotographic characteristics are affected by the amount of the surface treatment agent attached to the metal oxide fine particles after the surface treatment. When the surface treatment agent is a silane coupling agent, the amount of adhesion is determined from the Si intensity in the fluorescent X-ray analysis and the main metal element intensity of the metal oxide. The preferable Si intensity in the fluorescent X-ray analysis is in the range of 1.0 × 10 ^{−5 to} 1.0 × 10 ⁻³ of the main metal element strength of the metal oxide. When the Si intensity is less than the above lower limit, image quality defects such as fog tend to occur. On the other hand, when the Si intensity exceeds the above upper limit, density tends to decrease due to an increase in residual potential. is there.

  Examples of the binder resin include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride. -Known polymer resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, and charge transport resin having a charge transport group And conductive resins such as polyaniline. Among these, resins insoluble in the coating solvent for the upper layer (charge generation layer 5) are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins and the like are particularly preferably used.

  The undercoat layer 4 is formed by dispersing the conductive material in a binder resin to prepare a coating solution for forming an undercoat layer, and applying the solution on a support. The ratio between the metal oxide fine particles and the binder resin in the coating solution for forming the undercoat layer can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.

  Various additives can be used in the coating liquid for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting materials such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium Chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent. The silane coupling agent is used for the surface treatment of the metal oxide fine particles, but it can also be used as an additive added to the coating solution.

  As a silane coupling agent used here, the thing similar to the coupling agent used for the surface treatment of metal oxide fine particles can be used.

  Zirconium chelate compounds include: zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthenic acid Zirconium, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium Examples include lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  Examples of the solvent used for the coating solution for forming the undercoat layer include known organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, methanol, ethanol, n-propanol, iso-propanol, n-butanol and the like. Aliphatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether or Examples include linear ether solvents, and ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  In addition, as a method for dispersing the metal oxide fine particles, there are a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, and a medialess disperser such as an agitator, an ultrasonic disperser, a roll mill, and a high-pressure homogenizer. Available. Furthermore, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which a fine flow path is dispersed in a high pressure state.

  As a coating method for forming the undercoat layer 4, a normal method such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, or a curtain coating method is used. Can do.

  The undercoat layer 4 preferably has a Vickers strength of 35 or more. The thickness of the undercoat layer 4 is preferably 15 μm or more, and more preferably 20 to 50 μm.

  Further, the surface roughness of the undercoat layer 4 is adjusted to λ from ¼ n (n is the refractive index of the upper layer) of the exposure laser wavelength λ used in order to prevent moire images. Resin particles can be added to the undercoat layer 4 to adjust the surface roughness. As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used.

  Further, the undercoat layer 4 can be polished to adjust the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  Further, an intermediate layer may be provided between the undercoat layer 4 and the upper layer in order to improve electrical characteristics, improve image quality, improve image quality maintainability, and improve photosensitive layer adhesion. As the binder resin used for the intermediate layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resins such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atom, etc. An organometallic compound containing These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  Among these, organometallic compounds containing zirconium or silicon are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Examples of organic zirconium compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthenic acid. Zirconium, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  As organic silicon compounds, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane , Vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ- Examples include aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. Among these, particularly preferable silicon compounds are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N Examples include silane coupling agents such as phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of organic titanium compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium Examples include lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the organoaluminum compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  As the solvent used for forming the intermediate layer, known organic solvents, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatics such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol Alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  As a coating method for forming the intermediate layer, a usual method such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, or a curtain coating method can be used. .

  In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer.However, if the film thickness is too large, the electrical barrier becomes too strong, causing desensitization and potential increase due to repetition. It tends to be easier. Therefore, the film thickness of the intermediate layer is preferably 0.1 to 3 μm. Further, the intermediate layer in this case may be used together as the undercoat layer 4.

  On the undercoat layer 4, a charge generation layer 5 is disposed. The charge generation layer 5 includes a charge generation material.

  As the charge generation material, for example, phthalocyanine pigments such as metal-free phthalocyanine, oxytitanium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine can be used. In addition, quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments, phthalocyanine pigments, and the like can be used as charge generation materials. Moreover, these charge generation materials can be used individually or in mixture of 2 or more types. Among these, at least one selected from metal-free phthalocyanine, oxytitanium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine is preferable.

  In particular, it is strong at least 7.7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 ° of the Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays. Metal-free phthalocyanine crystals having diffraction peaks, strong diffraction peaks at Bragg angles (2θ ± 0.2 °) of CuKα characteristic X-rays of at least 7.4 °, 16.6 °, 25.5 ° and 28.3 ° A chlorogallium phthalocyanine crystal having CuKα characteristic X-ray with a Bragg angle (2θ ± 0.2 °) of at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25. Hydroxygallium phthalocyanine crystals with strong diffraction peaks at 1 ° and 28.3 °, and at least 9.6 °, 24.1 ° and 27.2 ° Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays Strong times At least one selected from titanyl phthalocyanine crystal having a peak is preferred.

  Furthermore, as a chlorogallium phthalocyanine crystal, in an X-ray diffraction spectrum using CuKα as a radiation source, 7.4 °, 16.6 °, 25.5 °, 28.3 of Bragg angles (2θ ± 0.2 °) are used. Chlorogallium phthalocyanine crystal (I-1) having a strong diffraction peak at °, strong diffraction at 6.8 °, 17.3 °, 23.6 ° and 26.9 ° of Bragg angle (2θ ± 0.2 °) Chlorogallium phthalocyanine crystal having a peak (I-2) and Bragg angles (2θ ± 0.2 °) of 8.7 ° to 9.2 °, 17.6 °, 24.0 °, 27.4 °, Chlorogallium phthalocyanine crystal (I-3) having a strong diffraction peak at 28.8 ° is preferred.

  As the dichlorotin phthalocyanine crystal, in the X-ray diffraction spectrum using CuKα as a radiation source, Bragg angles (2θ ± 0.2 °) of 8.3 °, 12.2 °, 13.7 °, 15.9 °, Dichlorotin phthalocyanine crystal (I-4) having a strong diffraction peak at 18.9 °, 28.2 °, Bragg angle (2θ ± 0.2 °) of 8.5 °, 11.2 °, 14.5 ° Dichlorotin phthalocyanine crystal (I-5) having a strong diffraction peak at 27.2 °, 8.7 °, 9.9 °, 10.9 °, 13.1 of Bragg angle (2θ ± 0.2 °) Dichlorotin phthalocyanine crystal (I-6) having strong diffraction peaks at °, 15.2 °, 16.3 °, 17.4 °, 21.9 °, 25.5 °, and Bragg angle (2θ ± 0. 9.2 °, 12.2 °, 13.4 °, 14.6 °, 17.0 °, Dichlorotin phthalocyanine crystal having strong diffraction peaks at 5.3 ° (I-7) are preferred.

  The hydroxygallium phthalocyanine crystal has a Bragg angle (2θ ± 0.2 °) of 7.7 °, 16.5 °, 25.1 °, and 26.6 ° in an X-ray diffraction spectrum using CuKα as a radiation source. Hydroxygallium phthalocyanine crystal (I-8) having a strong diffraction peak, strong diffraction peaks at 7.9 °, 16.5 °, 24.4 ° and 27.6 ° of the Bragg angle (2θ ± 0.2 °) Having hydroxygallium phthalocyanine crystal (I-9), Bragg angle (2θ ± 0.2 °) of 7.0 °, 7.5 °, 10.5 °, 11.7 °, 12.7 °, 17.3 7. Hydroxygallium phthalocyanine crystal (I-10) having strong diffraction peaks at °, 18.1 °, 24.5 °, 26.2 °, 27.1 °, 7. Bragg angle (2θ ± 0.2 °). 5 °, 9.9 °, 12.5 °, 16.3 °, 18 Hydroxygallium phthalocyanine crystal (I-11) having strong diffraction peaks at .6 °, 25.1 °, and 28.3 °, and 6.8 ° and 12.8 ° of Bragg angle (2θ ± 0.2 °) , Hydroxygallium phthalocyanine crystals (I-12) having strong diffraction peaks at 15.8 ° and 26.0 ° are preferable.

  As the metal-free phthalocyanine crystal, X-type metal-free phthalocyanine crystal (I-13) is preferable.

As an oxytitanium phthalocyanine crystal, in an X-ray diffraction spectrum using CuKα as a radiation source, a Bragg angle (2θ ± 0.2 °) of 9.3 °, 10.6 °, 13.2 °, 15.1 °, Oxytitanium phthalocyanine crystal (I-14) having strong diffraction peaks at 15.7 °, 16.1 °, 20.8 °, 23.3 °, 26.3 °, Bragg angle (2θ ± 0.2 °) 7.6 °, 10.2 °, 12.6 °, 13.2 °, 15.1 °, 16.3 °, 17.3 °, 18.3 °, 22.5 °, 24.2 ° Oxytitanium phthalocyanine crystal (I-15) having strong diffraction peaks at 25.3 °, 28.6 °, and 9.7 °, 11.7 °, 15.0 of Bragg angle (2θ ± 0.2 °) Oxytitanium phthalocyanine crystals with strong diffraction peaks at 23.5 ° and 27.3 ° (I-16) are preferred. Table 1 shows the ionization potential values of the phthalocyanine crystals ((I-1) to (I-16)).

ここで、イオン化ポテンシャル（Ｉｐ）の測定方法としては、大気雰囲気型紫外線光電子分析装置（例えば、理研計器（株）製、表面分析装置ＡＣ−１）による方法や、真空紫外分光法（ＵＰＳ）による方法等が挙げられる。なお、本発明において、イオン化ポテンシャルは、大気雰囲気型紫外線光電子分析装置による方法を用いて、例えば、下記の装置及び条件で測定できる。

Here, as a measuring method of the ionization potential (Ip), an atmospheric atmosphere type ultraviolet photoelectron analyzer (for example, a surface analyzer AC-1 manufactured by Riken Keiki Co., Ltd.) or a vacuum ultraviolet spectroscopy (UPS) is used. Methods and the like. In the present invention, the ionization potential can be measured using, for example, the following apparatus and conditions using a method using an atmospheric-type ultraviolet photoelectron analyzer.

Ionization potential measurement device: Riken Keiki Co., Ltd., surface analysis device AC-1 (this device counts photoelectrons by ultraviolet excitation in the atmosphere and analyzes the sample surface, and uses a low energy electron counting device. ),
Environmental temperature during measurement: 20 ° C
Relative humidity during measurement: 60%
Counting time: 10 seconds / 1 point
Light intensity setting: 50 μW / cm ²
Light intensity correction: Corrected by the attached program with the above settings,
Energy scanning range: 3.4 to 6.2 eV,
UV spot diameter: 1mm SQ,
Unit photon: 1 × 10 ¹⁰ / cm ² · sec.

  When measuring the ionization potential, the measurement sample is set so that the distance between the powder surface of the measurement sample and the ultraviolet irradiation position is 2 mm in an aluminum pan having a depth of 1 mm and a diameter of 7 mm. To do.

  The ionization potential is a straight line corresponding to the background in a curve obtained with the square root of the count value (CPS) on the vertical axis and the ultraviolet excitation energy (eV) on the horizontal axis according to the work function calculation program attached to the apparatus. It is obtained by the intersection of a straight line obtained by extrapolating the part and a straight line obtained by extrapolating the straight line part corresponding to the place where the count value has rapidly increased.

  FIG. 4 is a curve showing an example of the relationship between the square root of the count value (CPS) measured by the ionization potential measuring apparatus and the ultraviolet excitation energy (eV). Hereinafter, a method for obtaining the ionization potential Ip from the curve shown in FIG. 4 will be described. In FIG. 4, a curve 10 shows the relationship between the measured CPS square root and the ultraviolet excitation energy. The curve 10 includes a straight line portion 12 corresponding to the background, and a straight line portion corresponding to a portion where the count value gradually increases as the ultraviolet excitation energy increases and the count value rapidly increases due to further increase of the ultraviolet excitation energy. There are eleven. In FIG. 4, the ionization potential IP is a value (eV) on the horizontal axis (ultraviolet excitation energy axis) of the intersection 13 of the extrapolated line (broken line) by extrapolating the straight portions 12 and 11.

  The charge generation layer 5 can be formed, for example, by dispersing a charge generation material in a binder resin to produce a charge generation layer forming coating solution and applying the coating solution on the undercoat layer 4.

  Examples of the binder resin include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene copolymer resin, acrylonitrile. -Butadiene copolymer, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, phenol -Formaldehyde resin, polyacrylamide resin, polyamide resin, poly-N-vinylcarbazole resin and the like can be used. These binder resins can be used singly or in combination of two or more.

  The mixing ratio of the charge generation material and the binder resin in the charge generation layer forming coating solution is preferably 10: 1 to 1:10.

  Solvents used for dispersion of the charge generating material include known organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, fats such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol. Aromatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether And ether solvents such as methyl ether solvent, methyl acetate, ethyl acetate and n-butyl acetate. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  Examples of the method for dispersing the charge generating material in the resin include a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, and a horizontal sand mill, and a medialess dispersing machine such as an agitator, an ultrasonic dispersing machine, a roll mill, and a high-pressure homogenizer. Available. Furthermore, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which a fine flow path is dispersed in a high pressure state.

  As a coating method for forming the charge generation layer 5, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method can be used. .

  The film thickness of the charge generation layer 5 is preferably set in the range of 0.01 to 5 μm, more preferably 0.05 to 2.0 μm.

  A charge transport layer 6 is disposed on the charge generation layer 5, that is, on the side farthest from the conductive support 2. The charge transport layer 6 includes one or more charge transport materials, fluorine resin particles, and a fluorine graft polymer.

  Specific examples of charge transport materials include triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, and groups composed of these compounds. Examples thereof include a polymer having a main chain or a side chain. These charge transport materials may be used alone or in combination of two or more.

  Among these charge transport materials, benzidine compounds, triarylamine compounds, and mixtures of these compounds are preferably used. Here, specific examples of triarylamine compounds are shown in Table 2 together with ionization potential values, and specific examples of benzidine compounds are shown in Table 3 together with ionization potential values. The ionization potential can be measured by the same method as described above.

  The fluorine resin fine particles are fine particles containing a fluorine resin. Here, the fluorine-based resin is a resin containing a fluorine atom. For example, a tetrafluoroethylene resin, a trifluorinated ethylene resin, a hexafluoropropylene resin, a vinyl fluoride resin, a vinylidene fluoride resin, a two fluorine resin. Among these, it is desirable to use one of them alone or two or more appropriately selected from these. Of these, tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

  The primary particle size of the fluororesin particles is preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. When the primary particle size is less than 0.05 μm, the particles tend to aggregate at the time of dispersion. On the other hand, when the particle size exceeds 1 μm, image quality defects tend to occur.

  The fluorine-based graft polymer is a graft polymer containing a fluorine atom. The fluorine-based graft polymer has an effect of improving the dispersion stability of the coating solution and preventing aggregation during the formation of the coating film.

  The fluorine-based graft polymer is obtained by copolymerizing a macromonomer, which is a relatively low molecular weight oligomer having a molecular weight of 1000 to 10,000, having a polymerizable functional group at one end of each molecular chain, and a fluorine-based polymerizable monomer. It has a structure in which the main chain is a fluoropolymer and the macromonomer polymer is in a branch.

  As the macromonomer, those having an affinity for the resin to which the graft polymer is added are selected. For example, polymers and copolymers containing acrylic acid esters, methacrylic acid esters, styrene compounds as monomer units, etc. Is mentioned. Moreover, as a fluorine-type polymer, it is a polymer containing the polymerizable monomer (fluorine-type polymerizable monomer) which has a fluorine atom in a molecule | numerator as a monomer unit. As a polymerizable monomer which has a fluorine atom in a molecule | numerator, what is shown by following formula (IV-1)-(IV-6) is mentioned, for example. These can be used alone or in combination of two or more.

［上記式（ＩＶ−１）〜（ＩＶ−６）中、Ｒ^１は水素原子又はメチル基を示し、Ｒ^２は水素原子、ハロゲン原子、アルキル基、アルコキシ基又はニトリル基を示し、Ｒ^２が複数存在する場合にはそれらの官能基は上記の官能基のうちの同一であっても異なっていてもよい。ｎは１以上の整数、ｍは１〜５の整数、ｋは１〜４の整数を示し、ｍ及びｋはｍ＋ｋ＝５となるように選択される。］

[In the above formulas (IV-1) to (IV-6), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a nitrile group, and R ² represents When a plurality of functional groups are present, these functional groups may be the same or different from the above functional groups. n represents an integer of 1 or more, m represents an integer of 1 to 5, k represents an integer of 1 to 4, and m and k are selected so that m + k = 5. ]

  The content of the fluorinated polymer in the fluorinated graft polymer is preferably from 5 to 90% by weight, more preferably from 10 to 70% by weight, based on the fluorinated graft polymer. If the content of the fluoropolymer is less than 5% by weight, the modification effect of hydrophobization tends to be insufficient. On the other hand, if the content exceeds 90% by weight, compatibility with the macromonomer is caused during polymerization. Tend to get worse.

  The type and content of one or more charge transport materials, fluorine resin particles, and fluorine graft polymer in the charge transport layer 6 are adjusted to satisfy the condition of the above formula (1). . In the photoreceptor 1 shown in FIG. 1, not only the charge transport property of the charge transport layer 6 is particularly excellent, but also charges are injected from the charge generation layer 5 into the charge transport layer 6 to pass through the charge transport layer. It is considered that the charge injection property relating to the matching between the charge generation material and the charge transport material is particularly excellent when the charge moves.

  The content of the fluororesin particles is not particularly limited as long as the condition of the above formula (1) is satisfied, but is preferably 0.1 to 40 wt%, more preferably 1 to 30 wt% with respect to the total amount of the charge transport layer 6. If the content of the fluororesin particles is less than 0.1 wt%, the modification effect due to the dispersion of the fluororesin particles tends to be insufficient. On the other hand, if the content exceeds 40 wt%, the light transmission property is lowered and repeated. The residual potential tends to increase due to use.

  The charge transport layer 6 may further contain inorganic particles. Examples of the inorganic particle material include alumina, silica (silicon dioxide), titanium oxide, zinc oxide, cerium oxide, zinc sulfide, magnesium oxide, copper sulfate, sodium carbonate, magnesium sulfate, potassium chloride, calcium chloride, sodium chloride, Examples thereof include nickel sulfate, antimony, manganese dioxide, chromium oxide, tin oxide, zirconium oxide, barium sulfate, aluminum sulfate, silicon carbide, titanium carbide, boron carbide, tungsten carbide, and zirconium carbide. These may be used alone or in combination of two or more. Among these, silica is preferable.

  The silica particles are preferably produced by a chemical flame CVD method. As a specific example, silica particles are obtained by gas phase reaction of chlorosilane gas in a high-temperature flame of oxygen-hydrogen mixed gas or hydrocarbon-oxygen mixed gas. The method is preferred.

  In addition, as the inorganic particles, particles having a hydrophobic surface are preferable. As the hydrophobizing agent, for example, a siloxane compound, a silane coupling agent, a titanium coupling agent, a polymer fatty acid or a metal salt thereof is used.

  Examples of the siloxane compound include polydimethylsiloxane, dihydroxypolysiloxane, octamethylcyclotetrasiloxane, and examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-aminoethyl). Aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxy Silane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimeth Examples include xylsilane and p-methylphenyltrimethoxysilane.

  The primary particle size of the inorganic particles is preferably 0.005 to 2.0 μm, and more preferably 0.01 to 1.0 μm. When the primary particle diameter of the inorganic fine particles is less than 0.005 μm, sufficient mechanical strength of the photoreceptor surface tends to be difficult to obtain, and aggregation during dispersion tends to proceed easily. On the other hand, if it exceeds 2 μm, the surface roughness of the photoreceptor increases, the cleaning blade is worn and damaged, the cleaning characteristics deteriorate, and image blur tends to occur.

  The content of the inorganic particles is preferably from 0.1 to 30 wt%, more preferably from 1 to 20 wt%, based on the total amount of the charge transport layer 6. If the content of the inorganic particles is less than 1 wt%, the modification effect due to the dispersion of the inorganic particles tends to be insufficient. On the other hand, if the content exceeds 30 wt%, the residual potential tends to increase due to repeated use.

  The charge transport layer 6 can be formed, for example, by applying a coating liquid for forming a charge transport layer in which the above-described components and binder resin are dissolved in an appropriate solvent and drying the coating solution on the charge generation layer 5. it can.

  Examples of the binder resin include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene copolymer resin, acrylonitrile. -Butadiene copolymer resin, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, Insulating resins such as phenol-formaldehyde resin, polyacrylamide resin, polyamide resin, chlorine rubber, and polyvinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. Organic photoconductive polymers. These binder resins can be used singly or in combination of two or more.

  Examples of the solvent used for forming the charge transport layer 6 include known organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, methanol, ethanol, n-propanol, iso-propanol, and n-butanol. Aliphatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether Examples include chain ether solvents, ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. Also, what are these solvents? One kind can be used alone, or two or more kinds can be mixed and used. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent. Further, the blending ratio of the charge transport material and the binder resin in the charge transport layer forming coating solution is preferably 10: 1 to 1: 5.

  As a method for dispersing the fluorine-based resin particles and further inorganic particles in the charge transport layer 6, a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirring, an ultrasonic dispersing machine, a roll mill, Medialess dispersers such as high-pressure homogenizers can be used. Furthermore, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which a fine flow path is dispersed in a high pressure state.

  Examples of the dispersion of the coating liquid for forming the charge transport layer 6 include a method of dispersing fluorine resin particles and inorganic particles in a solution of a binder resin, a charge transport material and the like dissolved in a solvent.

  As a coating method for forming the charge transport layer 6, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method can be used. .

  The film thickness of the charge transport layer 6 is preferably 5 to 50 μm, more preferably 10 to 40 μm.

  As shown in FIG. 2, the photoreceptor 1 may include a single-layer type photosensitive layer 8. The single-layer type photosensitive layer includes one or more charge generation materials, one or more charge transport materials, fluorine resin particles, and a fluorine graft polymer. In addition, the thing similar to what was mentioned above can be used for said each component, and the kind and content of said each component are adjusted so that the conditions of said Formula (1) may be satisfy | filled.

  The single-layer type photosensitive layer 8 can be formed by a known method. For example, the above-mentioned components and binder resin are dissolved in a solvent to prepare a single-layer type photosensitive layer forming coating solution, Can be formed on the lower layer (undercoat layer 4 in FIG. 4) and dried. The film thickness of the single-layer type photosensitive layer 8 is set within a normal range.

  As shown in FIG. 3, the photoreceptor 1 may be provided with a protective layer 7 on the photosensitive layer 3 (the charge transport layer 6 in FIG. 3). The protective layer 7 is configured using a commonly used material. When the protective layer 7 is provided, the wear resistance of the photosensitive layer 3 is further improved to improve the life of the photosensitive member, the matching with the developer is improved, the charging of the electrophotographic photosensitive member is performed. It is possible to prevent chemical change of the photosensitive layer 3 at the time.

  Examples of the protective layer 7 include an insulating resin layer, a charge transporting protective layer made of a polymer compound imparted with charge transporting properties, or a resistance control type surface protective layer in which a resistance control agent such as a metal oxide is dispersed. Can be mentioned.

  In the photosensitive member described above, the photosensitive layer 3 contains an antioxidant, a light stabilizer, a heat stabilizer in the photosensitive layer 3 for the purpose of preventing deterioration of the photosensitive member due to ozone, nitrogen oxide, or light or heat generated in the electrophotographic apparatus. Additives such as stabilizers can be added. Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones and their derivatives, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzoazole, dithiocarbamate, and tetramethylpipen. Further, for the purpose of improving the smoothness of the surface, a leveling agent such as silicone oil can be added to the layer farthest from the support 2.

  The photoreceptor of the present invention described above can be used in electrophotographic apparatuses such as light lens copying machines, laser beam printers that emit near-infrared light or visible light, digital copying machines, LED printers, and laser facsimiles. The photoreceptor of the present invention can be used in combination with a one-component or two-component developer. Further, the photoreceptor of the present invention can provide good characteristics with little occurrence of current leakage even in a contact charging method using a charging roller or a charging brush.

(Electrophotographic equipment)
FIG. 5 is a schematic configuration diagram showing a preferred embodiment of the electrophotographic apparatus of the present invention. The electrophotographic apparatus 100 shown in FIG. 5 is a tandem type, so-called intermediate transfer type electrophotographic apparatus, and includes four image forming units 120a, 120b, 120c, and 120d, and includes four image forming units. 120 a to 120 d are arranged in parallel along a part of the intermediate transfer body 108.

  Here, each of the image forming units 120a to 120d includes drum-shaped electrophotographic photoreceptors 1a to 1d, and the electrophotographic photoreceptors 1a to 1d have a predetermined circumference in a predetermined direction (counterclockwise on the paper surface). It can be rotated at a speed (process speed). The electrophotographic photoreceptor is the above-described photoreceptor of the present invention.

  For each of the electrophotographic photoreceptors 1a to 1d, charging devices 103a to 103d for charging the photoreceptor along the rotation direction, developing devices 102a to 102d for developing a latent image and forming a toner image, toner Primary transfer devices 104a to 104d and cleaning devices 106a to 106d for sequentially transferring the image to the intermediate transfer member 108 are arranged. The developing devices 102a to 102d can be supplied with toners of four colors, yellow (Y), magenta (M), cyan (C), and black (K), contained in a toner cartridge (not shown). Color images can be formed as well as images. The electrophotographic apparatus 100 has a mode for increasing the process speed when outputting a black-and-white image than when outputting a color image.

  The primary transfer devices 104a to 104d are in contact with the electrophotographic photosensitive members 1a to 1d through the intermediate transfer member 108, respectively.

  The developing devices 102a to 102d are arranged in the order of Y, M, C, and K toner colors in FIG. 1, but this is in accordance with the image forming method of the system such as M, Y, C, and K, for example. And an appropriate order can be set.

  Further, an exposure device 107 (ROS (Raser Output Scanner)) that exposes a charged photoreceptor to form an electrostatic latent image is disposed at a predetermined position of the electrophotographic apparatus 100. Laser light emitted from the exposure device 107 is branched into laser light 105a to 105d, and irradiated onto the surfaces of the electrophotographic photoreceptors 1a to 1d after charging in the image forming units 120a to 120d. . Thus, the charging, exposure, development, primary transfer, and cleaning processes are sequentially performed in the rotation process of the electrophotographic photoreceptors 1a to 1d, and the toner images of the respective colors are transferred onto the intermediate transfer body 108 in an overlapping manner.

  Here, the charging devices 103a to 103d can adopt a conventionally non-contact method using a corotron or scorotron, or a contact charging method using a charging roll, a charging brush, a charging film, a charging tube, or the like.

  In the contact charging method, the surface of the photosensitive member is charged by applying a voltage to a conductive member brought into contact with the surface of the photosensitive member. The shape of the conductive member may be any of a brush shape, a blade shape, a pin electrode shape, a roller shape, and the like, but a roller-like member is particularly preferable. Since the electrophotographic apparatus 100 uses the above-described photoconductor of the present invention as the photoconductor, even a contact charging type charging device can reduce the wear of the photoconductor and obtain a good image. .

  Usually, the roller-shaped member is composed of a resistance layer, an elastic layer that supports them, and a core from the outside. Furthermore, a protective layer can be provided outside the resistance layer as necessary. The roller-like member rotates at the same peripheral speed as that of the photoreceptor without contacting the photoreceptor, and functions as a charging means. However, some driving means may be attached to the roller member, and the roller member may be charged by being rotated at a peripheral speed different from that of the photosensitive member.

  The core material is conductive and generally used is iron, copper, brass, stainless steel, aluminum, nickel, or the like. In addition, a resin molded product in which conductive particles or the like are dispersed can be used. The material of the elastic layer has conductivity or semiconductivity, and generally is a material in which conductive particles or semiconductive particles are dispersed in a rubber material.

  As the rubber material, EPDM, polybutadiene, natural rubber, polyisobutylene, SBR, CR, NBR, silicone rubber, urethane rubber, epichlorohydrin rubber, SBS, thermoplastic elastomer, norbornene rubber, fluorosilicone rubber, ethylene oxide rubber, etc. are used. .

Examples of conductive particles or semiconductive particles include carbon black, zinc, aluminum, copper, iron, nickel, chromium, titanium, and other metals, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O _3. Metal oxides such as —SnO ₂ , ZnO—TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , Sb ₂ O ₃ , In ₂ O ₃ , ZnO, and MgO can be used. These materials may be used alone or in combination of two or more.

As the material of the resistance layer and the protective layer, conductive particles or semiconductive particles are dispersed in a binder resin to control the resistance. The resistivity is preferably 10 ³ to 10 ¹⁴ Ωcm, more preferably It is 10 ⁵ to 10 ¹² Ωcm, more preferably 10 ⁷ to 10 ¹² Ωcm. The film thickness is preferably 0.01 to 1000 μm, more preferably 0.1 to 500 μm, and still more preferably 0.5 to 100 μm.

  Binder resins include acrylic resin, cellulose resin, polyamide resin, methoxymethylated nylon, ethoxymethylated nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin, PFA, FEP Polyolefin resin such as PET, styrene butadiene resin or the like is used.

  As the conductive particles or semiconductive particles, the same carbon black, metal, and metal oxide as the elastic layer are used. If necessary, an antioxidant such as hindered phenol and hindered amine, a filler such as clay and kaolin, and a lubricant such as silicone oil can be added.

  As a means for forming these layers, 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, a curtain coating method, or the like can be used.

  As a method of charging the photosensitive member using these conductive members, a voltage is applied to the conductive member. The applied voltage is preferably a DC voltage or a DC voltage superimposed with an AC voltage. As the voltage range, the DC voltage is preferably positive or negative 50 to 2000 V, more preferably 100 to 1500 V, depending on the required photoreceptor charging potential. When an alternating voltage is superimposed, the peak-to-peak voltage is preferably 400 to 1800 V, more preferably 800 to 1600 V, and even more preferably 1200 to 1600 V. The frequency of the AC voltage is preferably 50 to 20,000 Hz, more preferably 100 to 5,000 Hz.

  The intermediate transfer body 108 is supported with a predetermined tension by a drive roll 114, a backup roll 113, and a tension roll 115, and has the same peripheral speed as the electrophotographic photoreceptors 1a to 1d without causing deflection due to the rotation of these rolls. It can be rotated. A part of the intermediate transfer member 108 located between the drive roll 114 and the backup roll 113 is in contact with the electrophotographic photoreceptors 1a to 1d.

  As the intermediate transfer member 108, a conventionally known conductive thermoplastic resin can be used. For example, conductive resin-containing polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT Examples thereof include conductive thermoplastic resins such as blend materials. Among these, it is preferable to use a polyimide resin in which a conductive agent is dispersed from the viewpoint of excellent mechanical strength.

  As the conductive agent, a conductive polymer such as carbon black, metal oxide, or polyaniline can be used.

  When the intermediate transfer member is configured as a belt, the film thickness is preferably 50 to 500 μm, more preferably 60 to 150 μm, but can be appropriately selected according to the hardness of the material.

  As described in JP-A-63-311263, a polyimide resin belt in which a conductive agent is dispersed contains 5 to 20% by weight of carbon black as a conductive agent in a polyamic acid solution as a polyimide precursor. After dispersing and casting the dispersion on a metal drum and drying, the film peeled off from the drum is stretched at a high temperature to form a polyimide film, and further cut into an appropriate size to obtain an endless belt. Manufactured.

  The film forming is generally performed by injecting a polyamic acid solution film-forming stock solution in which a conductive agent is dispersed into a cylindrical mold and heating it to 100 to 200 ° C., for example, at a rotational speed of 500 to 2000 rpm. While rotating the mold, a film is formed by a centrifugal molding method. Next, the obtained film is demolded in a semi-cured state, covered with an iron core, and molded by proceeding with a polyimide reaction (polyamide acid ring-closing reaction) at a high temperature of 300 ° C. or higher to be fully cured. Also, the stock solution is cast on a metal sheet to a uniform thickness and heated to 100-200 ° C. to remove most of the solvent in the same manner as above, and then gradually raised to a high temperature of 300 ° C. or higher. There is also a method of forming a polyimide film. The intermediate transfer member may further have a surface layer.

  Further, the secondary transfer device 109 is disposed so as to contact the backup roll 113 via the intermediate transfer member 108. Further, the intermediate transfer member 108 that has passed between the backup roll 113 and the secondary transfer device 109 has its surface cleaned by, for example, a cleaning blade (not shown) disposed in the vicinity of the drive roll 114, and then The image forming process is used.

  A tray 111 is provided at a predetermined position in the electrophotographic apparatus 100. A transfer medium (paper) 112 is placed in the tray 111, and the transfer medium 112 in the tray 111 is conveyed between the secondary transfer unit 109 and the backup roll 113 by a conveyance unit (not shown). . The transfer medium 112 is further sequentially transferred between two fixing rolls 110 that are in contact with each other, and is discharged to the outside of the electrophotographic apparatus 100.

  Hereinafter, image formation using the above-described electrophotographic apparatus 100 will be described. In the electrophotographic apparatus 100, when the electrophotographic photoreceptors 1a to 1d are rotationally driven, the charging devices 103a to 103d are driven in conjunction with the rotation. Then, the surfaces of the electrophotographic photoreceptors 1a to 1d are uniformly charged to a predetermined polarity and potential (charging process). Next, the electrophotographic photoreceptors 1a to 1d whose surfaces are uniformly charged are exposed imagewise by laser beams 105a to 105d emitted from the exposure device 107, and electrostatic latent images are formed on the surfaces of the photoreceptors 1a to 1d. Is formed (exposure process).

  The electrostatic latent image is developed with toner from the developing devices 102a to 102d to form a toner image (developing process). The toner at this time is a two-component toner, but may be a one-component toner.

  This toner image is formed by the primary transfer bias applied to the intermediate transfer member 8 from the first transfer devices 104a to 104d in the process of passing through the interface (nip portion) between the photoreceptors 1a to 1d and the intermediate transfer member 8. By the applied electric field, primary (intermediate) transfer is sequentially performed on the outer peripheral surface of the intermediate transfer body 6 (intermediate (primary) transfer process).

  In this way, different color toner images are superimposed and transferred to the intermediate transfer member 108 by the image forming units 120a to 120d, and a color toner image is formed. This toner image is transferred from the intermediate transfer body 108 to the transfer medium 112 by the contact charging action by the secondary transfer means 109 (secondary transfer process), and the color toner image is fixed to the transfer medium 112 by the fixing roll 110. As a result, a color image is formed.

(Process cartridge)
FIG. 6 is a schematic configuration diagram showing a preferred embodiment of the process cartridge of the present invention. The process cartridge 200 is a combination of the electrophotographic photosensitive member 1, a charging device 201, a developing device 203, a cleaning device (cleaning means) 205, and an opening 207 for exposure using a mounting rail 216. It is.

  The process cartridge 300 is detachable from an electrophotographic apparatus main body including an exposure device 211, an intermediate transfer member 212, a transfer device 214, a fixing device 215, and other components not shown. The electrophotographic apparatus is configured together with the main body of the electrophotographic apparatus.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1)
To 170 parts by weight of n-butyl alcohol in which 4 parts by weight of polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.) is dissolved, 30 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (γ-amino) 3 parts by weight of propyltrimethoxysilane) was added and mixed and stirred to obtain a coating solution for forming an undercoat layer.

  This coating solution was dip-coated on a 30 mmφ aluminum support roughened by a honing treatment, and air-dried at room temperature for 5 minutes. Then, the support was heated to 50 ° C. in 10 minutes, put in a constant temperature and humidity chamber of 50 ° C. and 85% RH (dew point 47 ° C.), and subjected to a humidification hardening acceleration treatment for 20 minutes. Then, it put into the hot air dryer and dried for 10 minutes at 170 degreeC, and formed the undercoat layer.

  As a charge generation material, 10 parts by weight of hydroxygallium phthalocyanine (I-11, ionization potential = 5.31), 10 parts by weight of a polybutyral resin (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 280 parts by weight of n-butyl alcohol The mixture consisting of was dispersed in a sand mill for 4 hours. The obtained dispersion (charge generating layer forming coating solution) was dip coated on the undercoat layer and dried to form a charge generating layer having a thickness of 0.2 μm.

  Next, 40 parts by weight of a benzidine compound (above III-1, ionization potential = 5.28), 40 parts by weight of a triarylamine compound (above II-2, ionization potential = 5.39), bisphenol Z polycarbonate resin (molecular weight) 32,000) 120 parts by weight, and 0.5 parts by weight of tetrohydrofuran 560 parts by weight of a fluorine-based graft polymer solution (trade name: GF-300, manufactured by Toa Gosei Co., Ltd., hereinafter the same). Parts and 240 parts by weight of toluene were sufficiently dissolved and mixed. Thereafter, 20 parts by weight of tetrafluoroethylene resin particles (trade name: Lubron L2, manufactured by Daikin Industries, Ltd.) were added and mixed. Furthermore, it was dispersed with a high-pressure homogenizer to prepare a coating solution for forming a charge transport layer. The obtained coating solution was dip coated on the charge generation layer and dried to form a charge transport layer having a thickness of 26 μm.

  Here, of the benzidine compound (III-1) and the triarylamine compound (III-2) which are two kinds of charge transport materials contained in the charge transport layer, the benzidine compound (III-1) is a charge. It has an ionization potential smaller than the ionization potential of the generated material. The mass ratio X of the content of the benzidine compound (III-1) to the total content of the benzidine compound (III-1) and the triarylamine compound (III-2) was 50% by mass. It was. Table 4 shows data relating to the above formula (1).

  The electrophotographic characteristics of the obtained photoreceptor were evaluated as follows. First, the obtained photoconductor was mounted on a modified machine of a full-color copying machine (DocuCenter Color 400 CP) manufactured by Fuji Xerox Co., Ltd. having a contact charging device with the same configuration as in FIG. Using this full-color copying machine, the initial charging potential (VH) is 720 (-V) and the post-exposure potential (VL) is 350 (-V) in a high-temperature and high-humidity environment of 28 ° C. and 85% RH. The charge and exposure were adjusted, and a 10,000 sheet print test was performed using A4 size paper, and the subsequent VH, VL, residual potential (RP) after static elimination, and image quality were evaluated. Table 4 shows the obtained results.

  The photoconductor was incorporated in a DocuCenter Color 400 CP process cartridge and mounted on the full-color copying machine, and EA toner having a shape factor value SF1 = 132 was used as the toner.

(Example 2)
Implementation was performed except that the charge transport material in the coating liquid for forming a charge transport layer in Example 1 was only 80 parts by weight of the benzidine compound (III-1) and the fluorine-based graft polymer solution was changed to 0.7 parts by weight. A photoconductor was prepared in the same manner as in Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Example 3)
In the coating liquid for forming the charge transport layer of Example 1, the charge transport material was only 80 parts by weight of the triarylamine compound (II-2), and the fluorine graft polymer solution was changed to 0.3 parts by weight. A photoconductor was prepared in the same manner as in Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

Example 4
A photoconductor was prepared in the same manner as in Example 1 except that the fluorine-based graft polymer solution in the charge transport layer forming coating solution of Example 1 was changed to 0.1 parts by weight. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Example 5)
As the charge generation material of Example 1, chlorogallium phthalocyanine (I-1 above, ionization potential = 5.41) was used, and the charge transport material in the coating liquid for forming the charge transport layer was converted to a triarylamine compound (II-3). , Ionization potential = 5.32) 60 parts by weight and benzidine compound (III-3, ionization potential = 5.46) 20 parts by weight, except that the fluorine-based graft polymer solution was changed to 0.4 parts by weight. A photoconductor was prepared in the same manner as in Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Comparative Example 1)
A photoconductor was prepared in the same manner as in Example 1 except that the fluorine-based graft polymer solution in the coating solution for forming the charge transport layer in Example 1 was changed to 0.7 parts by weight. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Comparative Example 2)
Example 1 except that the charge transport material in the coating liquid for forming a charge transport layer of Example 1 is only 80 parts by weight of the benzidine compound (III-1) and the fluorine-based graft polymer solution is changed to 0.8 parts by weight. A photoconductor was prepared in the same manner as in Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Comparative Example 3)
Except for changing the charge transport material in the charge transport layer forming coating liquid of Example 1 to only 80 parts by weight of the triarylamine compound (II-2) and changing the fluorine-based graft polymer solution to 0.5 parts by weight, A photoconductor was prepared in the same manner as in Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Comparative Example 4)
A photoconductor was prepared in the same manner as in Example 1 except that the fluorine-based graft polymer solution was not added to the charge transport layer coating solution of Example 1. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

(Comparative Example 5)
Chlorogallium phthalocyanine (I-1, above, ionization potential = 5.41) was used as the charge generation material of Example 1, and the charge transport material in the charge transport layer coating solution was a triarylamine compound (II-3, ionization potential). = 5.32) Example 1 except that only 60 parts by weight and 20 parts by weight of a benzidine compound (III-3, ionization potential = 5.46) were used, and the fluorine-based graft polymer solution was changed to 0.8 parts by weight. A photoconductor was prepared in the same manner as described above. Table 4 shows data relating to the above formula (1). In addition, the electrophotographic characteristics of the photoreceptor were evaluated in the same manner as in Example 1. Table 4 shows the obtained results.

1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. It is a curve which shows an example of the relationship between the square root of the count value (CPS) measured by the ionization potential measuring apparatus, and ultraviolet excitation energy (eV). 1 is a schematic configuration diagram showing a preferred embodiment of an electrophotographic apparatus of the present invention. It is a schematic block diagram which shows suitable embodiment of the process cartridge of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photoreceptor, 2 ... Conductive support body, 3 ... Photosensitive layer.

Claims (4)

An electrophotographic photosensitive member having a conductive support and a photosensitive layer disposed on the conductive support,
The photosensitive layer contains one or more charge generation materials, one or more charge transport materials, fluorine resin particles, and a fluorine graft polymer.
A mass ratio X of the charge transport material having an ionization potential smaller than that of the charge generation material having a minimum ionization potential to the total amount of the charge transport material, and a mass ratio of the fluorine-based graft polymer to the fluorine-based resin particles An electrophotographic photosensitive member, wherein Y satisfies the condition represented by the following formula (1):
0.5 ≦ Y ≦ (0.02 × X) +1.5 (1)   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains a charge transport material having an ionization potential smaller than that of the charge generation material having a minimum ionization potential. The electrophotographic photosensitive member according to claim 1 or 2,
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;
A developing device for developing the electrostatic latent image to form a toner image;
A transfer device for transferring the toner image to a transfer medium;
An electrophotographic apparatus comprising: The electrophotographic photosensitive member according to claim 1 or 2,
At least one selected from a charging device for charging the electrophotographic photosensitive member, an exposure device for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and a cleaning device for cleaning the electrophotographic photosensitive member; ,
A process cartridge comprising:

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