JP2003066628A - Method for forming image and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which is excellent in the photosensitivity characteristics, stability of the characteristics for repeated use and mechanical durability, which is free from separation failure of a transferred body from a photoreceptor, and which generates no image failure, and to provide a method for forming an image. SOLUTION: An electrophotographic photoreceptor having a surface photosensitive layer into which a polymer compound having the structural unit expressed by general formula (1) is incorporated as a binder resin is used for the method for forming an image. The method includes a process of transferring a developer from the electrophotographic photoreceptor to a body to be transferred and then separating the body to be transferred from the photoreceptor surface by a mechanical separating means. In formula (1), each of R<1> , R<2> , R<3> , R<4> , R<5> , R<6> , R<7> and R<8> represents a hydrogen atom, halogen atom, 1-6C alkyl group which may have substituents, 4-10C cyclic hydrocarbon group which may have substituents or aryl group which may have substituents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and an image forming apparatus which have high durability and high separation performance of transferred materials.

[0002]

2. Description of the Related Art Conventionally, as a photoconductive material for an electrophotographic photosensitive member (hereinafter, also simply referred to as "photosensitive member"), Se,
Inorganic materials such as CdS and ZnO have been used, but in recent years, since they have low printing durability and problems such as toxicity and temperature characteristics, they are pollution-free, have excellent film-forming properties, and have a material selection. Organic photoconductive materials having a wide range have come to be used, and electrophotographic photoreceptors using these materials have been actively developed. As organic photoconductors using the organic photoconductive material, photoconductors having various photosensitive layer configurations such as a function separation type and a single layer type have been proposed.

The function-separated type photoreceptor has a charge generating layer in which a charge generating material is dispersed in a binder resin and a charge transporting material in which a charge transporting material which is a photoconductive material is dispersed in a binder resin, on a support. This is a configuration having a photosensitive layer having a laminated structure in which layers are stacked. This laminated structure has a structure in which a charge transport layer is stacked on a charge generation layer, an inverted two-layer structure in which a charge generation layer is stacked on a charge transport layer, and the like. The single-layer type photoreceptor has a structure in which the photosensitive layer on the support has a single-layer structure in which a charge generating material and a charge transporting material are dispersed in a binder resin. In particular, the function-separated type photoreceptor in which a charge transport layer is laminated on the charge generation layer as a photosensitive layer is excellent in electrophotographic characteristics and durability, has a high degree of freedom in material selection, and has various photoreceptor characteristics. It is widely used because it can

In these practically used organic photoreceptors, the main problem is durability, and in particular, abrasion of the film during repeated use, and charging potential due to electrical and chemical changes of the film. There is a problem that characteristic changes such as decrease and increase of residual potential are likely to occur. These issues are
Printing durability of the photosensitive layer in the image forming process, where the latent image is created by charging and exposure, the toner image is transferred to the transfer paper, and the residual toner on the surface of the photoconductor is removed with a blade, etc. Are not sufficient, and the main factors are that the organic photoconductive compound in the film is modified or decomposed by light, ozone, nitrogen oxides, etc. exposed during the image forming process. Therefore, in the organic photoreceptor, practically sufficient durability is not ensured.

In order to solve the above-mentioned problems, a method of using a charging member in contact with the surface of the photoconductor has been proposed as a means for reducing the amount of ozone generated by corona discharge inside the copying machine. It is effective.
However, this method has a drawback in that the number of members rubbing against the photoconductor increases, resulting in large film abrasion during repeated use.

The performance required of the electrophotographic photosensitive member in the image forming process is, for example, high surface potential when charged, high carrier retention rate, high photosensitivity, and even in all environments. That is, there is little variation in electrical characteristics. Further, it is required that the film has high strength, has excellent wear resistance in repeated use, and has high stability of electric characteristics throughout life. Furthermore, in order to improve the production efficiency, the electrophotographic photosensitive member is required to be prepared by a photosensitive member coating liquid that is physically and chemically stable. In order to meet these requirements, the role of the binder resin contained in the charge transport layer that also serves as the surface layer of the photoreceptor is very important.

A bisphenol A type polycarbonate resin is used as a binder resin for such a photoreceptor. However, since the bisphenol A type polycarbonate resin has high crystallinity, its solution is apt to cause gelation and has a drawback that the photoreceptor coating solution becomes unusable in a short period of time. Further, when a film is formed by coating, crystalline polycarbonate resin is deposited on the surface of the film to reduce the production efficiency, and when the produced photoconductor is used in a copying machine, the crystalline polycarbonate resin is deposited. Toner adheres to the resulting convex portion, and the toner in that portion remains without being removed by cleaning, resulting in an image defect due to defective cleaning. Furthermore, when the electrophotographic photoreceptor using this bisphenol A type polycarbonate resin as a binder resin is used in an electrophotographic copying machine, the surface of the photosensitive layer is easily scratched by being rubbed in the developing step or the cleaning step. It has the disadvantage that the layer is prone to wear.

Further, the use of a copolymer of bisphenol A and another molecule as a binder resin has been studied, but sufficient results have not been obtained yet. Further, JP-A-3-20768 proposes a technique for improving durability by using a bisphenol Z type polycarbonate resin as a binder resin on the surface of the photosensitive layer. A photoreceptor using this bisphenol Z-type polycarbonate resin as a binder resin has good printing durability and abrasion resistance, but has poor initial sensitivity and has a drawback that the residual potential rises when it is repeatedly used under high temperature and high humidity. Have
Further, Japanese Patent No. 2531852 proposes a polycarbonate resin having a new specific structure.

Furthermore, in order to make up for the drawbacks of the resin used,
It is considered to mix two or more kinds of resins. For example, Japanese Patent No. 1735555 describes bisphenol A type polycarbonate resin and bisphenol Z.
Is disclosed to mix with a type polycarbonate resin,
JP-A-6-317917 discloses mixing a polycarbonate resin synthesized from a symmetrical diol and a polycarbonate resin synthesized from an asymmetric diol. However, with the recent trend toward smaller drum diameters and faster processes, it is necessary to further improve the electrical, chemical and mechanical durability of the electrophotographic photoreceptor.

Here, Japanese Patent Laid-Open No. 1-257884,
JP-A-1-257988 and JP-A-1-292.
As disclosed in Japanese Patent No. 376, the toner image formed on the photoconductor is transferred onto a transfer target such as paper, the transfer target is separated from the photoconductor, and then the image is fixed on the transfer target. In the image forming apparatus, the separation claw is often attached for the purpose of improving the separation performance of the photoconductor and the transfer target. In this case, the sharp tip of the separation claw is brought into contact with the photosensitive member to separate the transfer target member, so that the surface of the photosensitive member is often scratched and an image defect often occurs. In order to improve the mechanical durability of the photoconductor in order to improve this, it is preferable to use a polycarbonate resin having a novel specific structure.
Although it is proposed in Japanese Patent No. 0589, it is still insufficient to cope with the recent speeding up of the process.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is not only excellent in photosensitivity characteristics, stability of characteristics in repeated use and mechanical durability, but also without causing separation failure of a transferred material from a photoreceptor, and image formation. An object of the present invention is to provide an image forming apparatus and an image forming method in which no defects occur.

[0012]

The present invention relates to an image forming method for forming an image by charging the surface of an electrophotographic photosensitive member and transferring the developed developer onto the electrophotographic photosensitive member to form an image. The photoconductor has, as a surface layer, a photosensitive layer containing at least a charge generation material, a charge transport material and a binder resin on a conductive substrate, and the binder resin has a structure represented by the following general formula (1). An image forming process, comprising a step of separating a transfer-receiving body, which contains a polymer compound having a unit and onto which a developer is transferred from the electrophotographic photosensitive body, from the surface of the electrophotographic photosensitive body by a mechanical separating means. Is the way.

[0013]

[Chemical 3]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or It represents an aryl group which may have a substituent. )

According to the present invention, by incorporating the polymer compound having the structural unit represented by the general formula (1) into the photosensitive layer, the structure is asymmetric, so that it is difficult to crystallize and the production efficiency is high. As the surface smoothness improves and there is no bulky group, it can be densely packed to form a strong film when it is dried and solidified from the solution, has excellent abrasion resistance, and is compatible with the charge transport material. Since it is excellent in electrical characteristics, it does not deteriorate electrical characteristics, and is excellent in photosensitivity even in an image forming method using a mechanical separating means, characteristic stability in repeated use, and mechanical durability.
An image defect does not occur without causing a separation failure of the transfer target member from the photosensitive member.

Further, the present invention is characterized in that the polymer compound has a viscosity average molecular weight of 30,000 or more and 70,000 or less.

According to the present invention, when the viscosity average molecular weight of the polymer compound is 30,000 to 70,000, the printing durability is remarkably lowered and the viscosity average molecular weight is less than 30,000. It is possible to avoid that the viscosity is larger than 70,000 and the viscosity of the coating solution is increased, it takes a long time to mix with the charge transport material, and unevenness of the coating film is likely to occur, thereby lowering productivity.

Further, the present invention is an image forming apparatus for forming an image by charging a surface of an electrophotographic photosensitive member and transferring a developer developed on the electrophotographic photosensitive member, at least on a conductive substrate. A photosensitive layer containing a charge generating material, a charge transporting material and a binder resin is used as a surface layer, and an electrophotographic photoreceptor containing a polymer compound having a binder resin having a structural unit represented by the following general formula (1) is mounted. An image forming apparatus comprising: a mechanical separating unit that separates a transfer-receiving member, on which a developer is transferred from the electrophotographic photosensitive member, from the surface of the electrophotographic photosensitive member.

[0019]

[Chemical 4]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or It represents an aryl group which may have a substituent. )

According to the present invention, by incorporating the polymer compound having the structural unit represented by the general formula (1) into the photosensitive layer, since the structure is asymmetric, it is difficult to crystallize and the production efficiency is high. As the surface smoothness improves and there is no bulky group, it can be densely packed to form a strong film when it is dried and solidified from the solution, has excellent abrasion resistance, and is compatible with the charge transport material. Since it is excellent in electrical characteristics, it does not deteriorate electrical characteristics, and also has excellent photosensitivity characteristics, characteristic stability in repeated use and mechanical durability even in an image forming apparatus provided with a mechanical separation means.
An image defect does not occur without causing a separation failure of the transfer target member from the photosensitive member.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In the image forming method according to the present invention, electrophotographic photoreceptors having various structures in which a photosensitive layer is provided on a conductive support can be used. Hereinafter, a detailed description will be given with reference to the drawings.

In FIG. 1, the charge transport layer 6 is formed on the charge generation layer 5.
FIG. 3 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member having a laminated photosensitive layer in which is laminated. On the conductive support 1,
This is a laminated-type photoreceptor provided with a photosensitive layer 4 formed by laminating a charge generation layer 5 containing a charge generation material 2 and a charge transport layer 6 containing a binder resin 7 and a charge transport material 3.

FIG. 2 is a sectional view schematically showing an example of an electrophotographic photoreceptor having a single-layer type photosensitive layer containing the charge generating material 2 and the charge transporting material 3 in the same layer. This is a single-layer type photoreceptor in which a photosensitive layer 14 containing a binder resin 7, a charge generation material 2 and a charge transport material 3 is provided on a conductive support 1.

FIG. 3 is a sectional view schematically showing an example having the intermediate layer 8 in the electrophotographic photosensitive member of FIG. This is a laminated-type photoreceptor in which an intermediate layer 8 is provided between a conductive support 1 and a photosensitive layer 4 similar to that shown in FIG.

FIG. 4 is a sectional view schematically showing an example having the intermediate layer 8 in the electrophotographic photoreceptor of FIG. This is a single-layer type photoreceptor in which an intermediate layer 8 is provided between the conductive support 1 and the photosensitive layer 14 similar to that shown in FIG.

The electrophotographic photoreceptor of the present invention is shown in FIGS.
Various layer structures can be adopted with No. 4 as a typical structure.

As the material of the conductive support 1, for example, metals such as aluminum, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold and platinum and alloy materials are used. You can In addition, aluminum on the surface,
It is possible to use a polyester film obtained by vapor-depositing or coating an aluminum alloy, tin oxide, gold, indium oxide, etc., paper and a metal film, plastic and paper containing conductive particles, and plastic containing a conductive polymer. These materials are used after being processed into a cylindrical shape, a cylindrical shape, or a thin film sheet shape.

An intermediate layer 8 may be introduced between the conductive support 1 and the photosensitive layer 4 or 14. The intermediate layer 8 is formed as an inorganic layer or an organic layer. As a material for the inorganic layer, for example, an aluminum anodic oxide coating, aluminum oxide, aluminum hydroxide or the like is used. As a material for the organic layer, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide and the like can be used. The organic layer contains, as an inorganic pigment, a metal such as aluminum, copper, tin, zinc and titanium, and conductive or semi-conductive fine particles such as a metal oxide such as zinc oxide, aluminum oxide and titanium oxide. Good. The crystal form of titanium oxide contained in the organic layer includes anatase type, rutile type, and amorphous, and any of them may be used, or two or more kinds may be mixed and used. Also,
The titanium oxide particles are preferably used by coating the surface thereof with a metal oxide such as Al ₂ O ₃ or ZrO ₂ or a mixture thereof.

As the binder resin contained in the mid layer 8, resins such as polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and polyamide can be used, and preferably. Polyamide resin is used. This is because the polyamide resin is the intermediate layer 8
It does not dissolve or swell in the solvent used in the photosensitive layer coating liquid for forming the photosensitive layer 4 or 14 on it, has excellent adhesiveness to the conductive support 1, and has flexibility. This is because it has properties required as the properties of the binder resin. Among the polyamide resins, alcohol-soluble nylon resin can be used more preferably. For example, 6-nylon, 66-nylon, 610
-Nylon, 11-nylon, 12-nylon, etc., so-called copolymerized nylon, and
There is a type in which nylon is chemically modified, such as N-alkoxymethyl modified nylon and N-alkoxyethyl modified nylon.

As the organic solvent used in the coating solution for the intermediate layer for forming the intermediate layer 8, a general organic solvent can be used. However, when an alcohol-soluble nylon resin, which is a more preferable polyamide resin, is used as the binder resin, a single or mixed organic solvent selected from the group of lower alcohols having 1 to 4 carbon atoms,
Alternatively, an organic solvent selected from the above lower alcohol group may be used, for example, dichloromethane, chloroform, 1,2.
-It is preferable to use a mixed organic solvent in which an organic solvent selected from the group consisting of organic solvents other than lower alcohols such as dichloroethane, 1,2-dichloropropane, toluene, tetrahydrofuran and 1,3-dioxolane is mixed. . By mixing an organic solvent selected from the lower alcohol group with an organic solvent other than the lower alcohol, the dispersibility of titanium oxide is improved as compared with the case where only the organic solvent of the lower alcohol group is used, and the storage stability of the coating solution is improved. It is possible to extend the period and regenerate the coating liquid. In addition, the conductive support 1 is dipped in the coating solution for the intermediate layer and applied to form the intermediate layer 8.
In forming the intermediate layer 8, coating defects and unevenness of the intermediate layer 8 are prevented, and the photosensitive layer 4 or 14 formed thereon can be uniformly coated, so that an electron having an excellent image characteristic without a film defect is formed. A photographic photoreceptor can be produced.

The intermediate layer 8 is obtained by adding a solvent and a binder resin to the above-mentioned inorganic pigment and dispersing the mixture using a dispersing machine such as a ball mill, a Dyno-mill or an ultrasonic oscillator to provide a conductive support for the intermediate layer. It is formed by applying on the body 1. As the coating method, a baker applicator, a bar coater, casting, spin coating and the like are used when the conductive support 1 is a sheet, and a spray method, a vertical ring method and a dip coating method are used when the conductive support 1 is a drum.

The charge generation layer 5 contains the charge generation material 2 which generates charges by light irradiation. Examples of the charge generation material 2 include perylene-based pigments such as perylene imide and perylene anhydride, polycyclic quinone-based pigments such as quinacridone and anthraquinone, phthalocyanine-based pigments such as metal phthalocyanine, metal-free phthalocyanine and halogenated metal-free phthalocyanine, and squarylium. Dyes, azurenium dyes, thiapyrylium dyes, and carbazole skeletons, styrylstilbene skeletons, triphenylamine skeletons, dibenzothiophene skeletons, oxadiazole skeletons, fluorenone skeletons, bisstilbene skeletons, distyryl oxadiazole skeletons or distyryl carbazole skeletons. Examples thereof include azo pigments.

Among these, pigments having a particularly high charge generation ability include metal-free phthalocyanine pigments, oxotitanyl phthalocyanine pigments, bisazo pigments containing a fluorene ring or a fluorenone ring, and bisazo pigments and trisazo pigments containing aromatic amines. Is mentioned. By using these pigments, a photoreceptor having high sensitivity can be provided. Further, among the oxotitanyl phthalocyanine pigments, the Bragg angle (2θ ± 0.
The crystalline type having a diffraction peak at 27.3 ° at 2 °) is more preferable because it has higher sensitivity.

In the charge generation layer 5, as a binder resin for increasing the binding property, for example, polyester resin, polyvinyl acetate resin, polyacrylic acid ester resin,
Polycarbonate resin, polyarylate resin, polyvinyl acetoacetal resin, polyvinyl propional resin, polyvinyl butyral resin, phenoxy resin, epoxy resin, urethane resin, melamine resin, silicone resin, acrylic resin, cellulose ester, cellulose ether and vinyl chloride-vinyl acetate. Various resins such as copolymer resins may be added.

In addition, the charge generation layer 5 may be, if necessary,
It may contain various conventionally known additives such as a leveling agent, a plasticizer, an antioxidant and a sensitizer for improving the coating property.

For the charge generation layer 5, fine particles of the above-mentioned charge generation material 2 or, if necessary, those to which a binder resin or the like is added are added to an appropriate organic solvent, and a ball mill, a sand grinder, a paint shaker and an ultrasonic wave are added. It is formed by applying a coating liquid prepared by pulverizing and dispersing with a disperser or the like onto the conductive support 1 or the intermediate layer 8. As the coating method, a baker applicator, a bar coater, casting, spin coating and the like are used when the conductive support 1 is a sheet, and a spray method, a vertical ring method and a dip coating method are used when the conductive support 1 is a drum.

The thickness of the charge generation layer 5 is 0.05 to 5 μm.
Is preferable, and more preferably 0.1 to 1 μm.

The charge transporting layer 6 is provided on the charge generating layer 5 and contains the charge transporting material 3 and the specific binder resin 7 which have the ability to receive the charge generated by the charge generating material 2 and transport it. Contained as.

The specific binder resin 7 is a polycarbonate resin A which is a polymer compound having a structural unit represented by the following general formula (1).

[0041]

[Chemical 5]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or It represents an aryl group which may have a substituent. ) Table 1 shows specific examples of the structural unit represented by the general formula (1).

[0043]

[Table 1]

Since the polycarbonate resin A has an asymmetric structure, it is difficult to crystallize, the production efficiency is improved, and the surface smoothness is improved. Further, since it does not have a bulky group, it can be densely packed to form a strong film when it is dried and solidified from a solution, and has excellent abrasion resistance. Furthermore, since the compatibility with the charge transport material 3 is excellent, the electrical characteristics are not deteriorated. By using the polycarbonate resin A, it is possible to obtain an electrophotographic photoreceptor having excellent photosensitivity characteristics, stability of characteristics upon repeated use, and mechanical durability.

With respect to the molecular weight of the polycarbonate resin A, it is preferable that the viscosity average molecular weight is 30,000 to 70,000 from the viewpoint of the electrical characteristics of the photoconductor, the repeated stability and the printing durability. When the viscosity average molecular weight is less than 30,000, the compatibility with the charge transport material 3 is high and the repeated stability of electric characteristics is excellent, but the printing durability is significantly deteriorated. When it is more than 70,000, the printing durability is improved, but the viscosity of the coating liquid for the charge transport layer is increased, and it takes a long time to mix with the charge transport material 3 and the coating film is likely to be uneven. And productivity is reduced.

The polycarbonate resin A may be used as a mixture with the polycarbonate resin B which is a polymer compound having a structural unit represented by the following general formula (2).

[0047]

[Chemical 6]

(Wherein R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ ,
R ¹⁴ , R ¹⁵ and R ¹⁶ are each a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms,
It represents a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent or an aryl group which may have a substituent. Z is
It is a group of atoms necessary for forming a carbocycle which may have a substituent or a heterocycle which may have a substituent. ) Table 2 shows specific examples of the structural unit represented by the general formula (2).

[0049]

[Table 2]

Since the polycarbonate resin B has a low gas permeability, it is possible to prevent the penetration of gases such as ozone and NO _x, which deteriorate the characteristics of the photoreceptor.

The polycarbonate resin B preferably has a viscosity average molecular weight of 15,000 to 35,000. When the viscosity average molecular weight is less than 15,000, HT white spots and black bands due to ozone and NO _x generated in the charging process are suppressed and the image stability is improved, but the printing durability is significantly reduced. , 35,000, the printing durability is improved, but the initial sensitivity is lowered.
The increase in residual potential and the decrease in image stability during repeated use are large.

A mixture of the polycarbonate resins A and B has excellent compatibility with the charge transport material 3 and excellent durability. By adding the polycarbonate resin B, it is possible to make it resistant to chemical changes such as ozone and NO _x .

The mixing ratio of the polycarbonate resin A and the polycarbonate resin B is such that A / B is 2 /
It is preferably in the range of 8 to 8/2. A / B is 2 /
When it is less than 8, that is, when the ratio of the polycarbonate resin A is low, the desired mechanical strength cannot be obtained, and scratches are likely to occur on the surface of the photoconductor. On the other hand, when A / B is larger than 8/2, that is, when the ratio of the polycarbonate resin B is low, the photoreceptor characteristics are deteriorated by ozone, NO _x, etc., and HT white spots and black bands are likely to occur in the image. Become.

As the charge transport material 3, an electron donating substance or an electron accepting substance is used. Examples of the electron-donating substance include poly-N-vinylcarbazole and its derivative, poly-γ-carbazolylethylglutamate and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative, and oxadiene. Azole derivative, imidazole derivative, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline derivative, phenylhydrazone, hydrazone derivative, triphenyl Amine compounds,
Tetraphenyldiamine compound, triphenylmethane compound, stilbene compound and 3-methyl-2-
Examples thereof include azine compounds having a benzothiazoline ring. The electron-accepting substance is a fluorenone derivative,
Dibenzothiophene derivative, indenothiophene derivative, phenanthrenequinone derivative, indenopyridine derivative, thioxanthone derivative, benzo [c] cinnoline derivative, phenazine oxide derivative, tetracyanoethylene, tetracyanoquinodimethane, bromanil, chloranil and benzoquinone Is mentioned. In particular, the butadiene-based compound represented by the following general formula (3), the styryl-based compound represented by the following general formula (4), and the amine-based compound represented by the following general formula (5) have high charge transporting ability, and therefore, are High sensitivity can be maintained even when the ratio of the resin 7 is high, which is more preferable.

[0055]

[Chemical 7]

(Wherein Ar ¹ , Ar ² , Ar ³ and Ar ⁴
Each represents an aryl group which may have a substituent, and Ar
^At least one of ^{1 to} Ar ⁴ is an aryl group having a substituted amino group as a substituent. n represents 0 or 1. )

[0057]

[Chemical 8]

[0058] (wherein, Ar ⁵ is an optionally substituted aryl group, Ar ⁶ is a phenylene group which may have a substituent, a naphthylene group, a biphenylene group or anthrylene group .R ¹⁷ Represents a hydrogen atom, a lower alkyl group or a lower alkoxy group, X represents a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent, and Y represents a substituent. Represents an aryl group which may have.

[0059]

[Chemical 9]

(In the formula, R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² and R ²³ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and p, q, t and u respectively represent An integer of 1 to 5 and r and s each represent an integer of 1 to 4.)

Specific examples of the butadiene compound represented by the general formula (3) are shown in Tables 3 and 4.

[0062]

[Table 3]

[0063]

[Table 4]

Specific examples of the styryl compound represented by the general formula (4) are shown in Tables 5 to 8.

[Table 5]

[0065]

[Table 6]

[0066]

[Table 7]

[0067]

[Table 8]

Specific examples of the amine compound represented by the general formula (5) are shown in Tables 9 and 10.

[0069]

[Table 9]

[0070]

[Table 10]

The charge transport layer 6 is made of these charge transport materials 3.
Are bonded to the binder resin 7.

In the charge transport layer 6, the ratio C / D of the charge transport material 3 (C) and the binder resin 7 (D).
Is a generally used weight ratio of 10/5 to 10/2.
It is about 5, but from the viewpoint of improving wear resistance, it is 10/15
10/24 are suitable. When C / D is larger than 10/15, that is, when the ratio of the charge transport material 3 is high,
The light sensitivity characteristic is good, may decrease the mechanical strength of the charging characteristics and film, HT white spots and black bands generated by ozone and NO _x generated by the charging process, the image stability is lowered To do. When C / D is smaller than 10/24, that is, when the ratio of the binder resin 7 is high, conversely, the charging property, the mechanical strength and the image stability are good, but
The deterioration of the photosensitivity becomes remarkable.

The charge transport layer 6 contains a plasticizer, an antioxidant, and a plasticizer in order to improve film-forming properties, flexibility and coating properties.
You may contain additives, such as a ultraviolet absorber and a leveling agent. As the antioxidant, an antioxidant generally used by adding it to a resin or the like can be used as it is. For example, vitamin E, hydroquinone,
Hindered amines, hindered phenols, para-phenylenediamines, aryl alkanes and their derivatives, organic sulfur compounds and organic phosphorus compounds can be used. As the leveling agent, silicone oils or polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is preferably 1 part by weight or less based on 100 parts by weight of the binder resin 7.

The charge transport layer 6 comprises the above charge transport material 3,
The binder resin 7 and the additives are dissolved or dispersed in an appropriate solvent to prepare a coating liquid, and the coating liquid is used as the intermediate layer 8 described above.
The charge-generating layer 5 and the charge-generating layer 5 are formed by applying the same method on the charge-generating layer 5. The solvent can be selected from the above-mentioned solvents listed as the solvent for dispersing the charge generating material 2. For example, alcohols such as methanol and ethanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone,
Ethers such as ethyl ether and tetrahydrofuran, aliphatic halogenated hydrocarbons such as chloroform, dichloroethane and dichloromethane, aromatic hydrocarbons such as benzene, chlorobenzene and toluene are used. A particularly preferred solvent is tetrahydrofuran.

The coating solution for the charge transport layer may be prepared by a general method in which the charge transport material 3, the binder resin 7 and the additive are weighed and dissolved in a predetermined amount of the solvent at the same time. A method in which the binder resin 7 is dissolved in a solvent and then the charge transport material 3 and additives are added and dissolved is particularly preferable. According to this method, the molecular dispersibility of the charge transport material 3 in the binder resin 7 is improved, and latent and local crystallization of the charge transport material 3 in the film is suppressed, so that the initial sensitivity can be improved. Improvement, potential stability at repeated use, and good image characteristics are imparted.

The thickness of the charge transport layer 6 is about 10 to 50 μm.
Is preferable, and more preferably about 10 to 35 μm.

In the case of a single-layer type photoreceptor, the above-mentioned charge generating material 2, charge transporting material 3 and binder resin 7 are dissolved or dispersed in the above-mentioned suitable solvent to prepare a coating solution,
The single-layer type photosensitive layer 14 is formed by applying the coating solution using the same method as the above-mentioned intermediate layer 8 and the like. The ratio of the charge transport material 3 to the binder resin 7 and the film thickness of the photosensitive layer 14 are the same as those in the case of the above-mentioned laminated type photoreceptor. The same additives as in the photosensitive layer 4 can be added to the photosensitive layer 14.

Next, an image forming apparatus equipped with the electrophotographic photosensitive member having the above-described structure will be described in detail with reference to the drawings. The image forming apparatus according to the present invention is not limited to the contents described below.

FIG. 5 is a block diagram showing a schematic structure of a laser printer 30 which is an image forming apparatus according to the present invention. The laser printer 30 includes an electrophotographic photoreceptor 11, a semiconductor laser 31, a contact charger 32, a developing device 33, a contact transfer charger 34, a fixing device 35, a cleaner 36, and a separating claw 37.

The photoconductor 11 is mounted on the laser printer 30 so as to be rotatable in the direction of arrow 41 by a driving means (not shown).

The contact charger 32 is provided upstream of the image forming point of the semiconductor laser 31 in the rotation direction of the photoconductor 11 and uniformly charges the surface of the photoconductor 11. A positive or negative DC voltage is applied to the conductive brush or the conductive roller of the contact charger 32. The DC voltage applied to the contact charger 32 is preferably -2000V to + 2000V. An AC voltage may be further superimposed on the DC voltage to apply a pulsating voltage. The AC voltage superimposed on the DC voltage is preferably a peak-to-peak voltage of 4000 V or less. When applying a voltage to the contact charger 32, a desired voltage may be applied instantaneously, but in order to protect the photoconductor 11, the applied voltage is gradually increased to apply the desired voltage. You may do it. The contact charger 32 may rotate either in the same direction as the photoconductor 11 or in the opposite direction, or may slide on the outer peripheral surface of the photoconductor 11 without rotating. Further, the contact charger 32 may be provided with a function of cleaning the residual toner on the surface of the photoconductor 11 and the cleaner 36 may be omitted.

The semiconductor laser 31 repeatedly scans the surface of the photoconductor 11 with the laser beam in its longitudinal direction (main scanning direction). An electrostatic latent image is formed on the surface of the photoconductor 11 by rotating the photoconductor 11 and scanning the laser beam as described above to form an image.

The developing device 33 is provided on the downstream side of the image formation point in the rotational direction, supplies toner to the photoconductor 11 and develops the electrostatic latent image as a toner image. As the developing device 33,
Either a contact type or a non-contact type may be used.

The contact transfer charger 34 is provided on the downstream side of the developing device 33 in the rotation direction and transfers the toner image onto the transfer paper 38 provided to the contact transfer charger 34 in synchronization with the exposure of the photoconductor 11. To do.

The fixing device 35 fixes the toner image on the transfer paper 38 conveyed to the fixing device 35 by a conveyor belt (not shown). Transfer paper 3 on which an image is formed in this way
8 is discharged.

The separating claw 37 is provided on the downstream side in the rotation direction of the contact transfer charger 34 so as to be in contact with the photoconductor 11, and prevents a separation error in which the transfer paper remains without being separated from the photoconductor 11. The material of the separation claw 37 is preferably engineering plastic such as polyimide and metal such as stainless steel. In addition, the separation claw 37 is provided with an actual open sho 63-65062.
As disclosed in Japanese Patent Laid-Open Publication No. 58-10456, a coating layer made of a material having a small frictional resistance may be provided at least on the surface of the tip end portion which comes into contact with the transfer paper.
As disclosed in the publication, a member that absorbs the impact due to the collision of the transfer paper may be provided. The angle formed by the tangent line at the contact point between the separation claw 37 and the photoreceptor 11 and the claw tip surface of the separation claw 37 is preferably maintained at 80 to 140 degrees on the transfer paper side.

The separating claw 37 extends the life of the photoconductor 11 by preventing the transfer paper from wrapping around the photoconductor 11, and has an extremely great effect on improving the reliability and durability of the entire image forming apparatus. . That is, once a separation failure occurs, the entire apparatus must be stopped and the transfer paper wrapped around the photoconductor 11 must be taken out. At this time, the surface of the photoconductor 11 may be scratched or subtle. While maintaining a certain position interval, the cleaning member and each electrode arranged around the photoconductor 11 are damaged or the position intervals thereof are changed. This can be avoided by providing the separation claw 37 to eliminate the separation failure.

The cleaner 36 is provided on the downstream side of the separation claw 37 in the rotation direction and on the upstream side of the contact charger 32 in the rotation direction, together with a discharge lamp (not shown), and cleans the toner remaining on the surface of the photoconductor 11. As the cleaner 36, either a blade cleaner or a contact cleaner such as a brush cleaner may be used.

The photoconductor 11 may be integrated with at least one of the contact charger 32, the developing unit 33 and the cleaner 36 to form a process cartridge. For example, the photoconductor 11 and the contact charger 3
2, a process cartridge incorporating all of the developing unit 33 and the cleaner 36, a photoconductor 11, a process cartridge incorporating the contact charger 32 and the developing unit 33, a process cartridge incorporating the photoconductor 11 and the cleaner 36, and a photoconductor A process cartridge incorporating the body 11 and the developing device 33 can be configured. Using such a process cartridge facilitates replacement in a printer or the like.

In such an image forming apparatus, since the above-mentioned specific polycarbonate resin is contained as the binder resin in the photosensitive layer which is the surface layer of the photosensitive member, it is excellent in abrasion resistance and mechanically separated like a separating claw. Even if the means is provided, the surface of the photoconductor is not scratched, the transfer target is not separated from the photoconductor, and the image is not defective.

(Example) (Example 1) Titanium oxide (TTO55A manufactured by Ishihara Sangyo Co., Ltd.)
7 parts by weight and copolymerized nylon resin (CM800 manufactured by Toray Industries, Inc.
0) 13 parts by weight was added to a mixed solvent of 159 parts by weight of methyl alcohol and 106 parts by weight of 1,3-dioxolane, and dispersed for 8 hours with a paint shaker to prepare a coating solution for the intermediate layer. The coating solution for the intermediate layer thus prepared was filled in a coating tank, and the conductive support had a diameter of 30 mm and a total length of 322.
mm drum-shaped support made of aluminum was immersed, pulled up and naturally dried to form an intermediate layer having a film thickness of 1 μm.

Next, 1 part by weight of titanyl phthalocyanine and butyral resin (# 6000-C manufactured by Denki Kagaku Kogyo Co., Ltd.)
1 part by weight was mixed with 98 parts by weight of methyl ethyl ketone and dispersed by a paint shaker to prepare a coating liquid for charge generation layer. The prepared charge generation layer coating liquid was applied onto the previously provided intermediate layer in the same manner as the above-mentioned intermediate layer, and naturally dried to form a charge generation layer having a thickness of 0.4 μm.

Next, 100 parts by weight of the butadiene compound represented by the structural formula (3-2) shown in Table 3 and the viscosity average molecular weight of 50 having the structural unit represented by the structural formula (1-1) shown in Table 1 are obtained. 80 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 21,500 (PCZ200 manufactured by Mitsubishi Gas Chemical Co., Inc.) having a structural unit represented by the structural formula (2-1) shown in Table 2. 2,6-bis-tert-butyl-4-methylphenol (Sumitomo Chemical Co., Ltd., Sumilizer BHT) (5 parts by weight) was mixed, and tetrahydrofuran was used as a solvent to give a solid content of 21.
A coating solution for the charge transport layer of wt% was prepared. The prepared charge transport layer coating solution was applied onto the charge generation layer previously provided in the same manner as the above-mentioned intermediate layer, and then dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

In this way, a laminated electrophotographic photosensitive member having the layer structure shown in FIG. 3 was produced.

Example 2 As a binder resin for the charge transport layer, a polycarbonate resin 1 having a structural unit represented by the structural formula (1-1) and a viscosity average molecular weight of 50,000 is used.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that only 60 parts by weight was used and the polycarbonate resin having the structural unit represented by the structural formula (2-1) was not used.

Example 3 As the binder resin for the charge transport layer, 120 parts by weight of the polycarbonate resin having the structural unit represented by the structural formula (1-1) was used, and the structural formula (2) was used.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 30 parts by weight of the polycarbonate resin having the structural unit represented by -1) was used.

Example 4 As the binder resin for the charge transport layer, 30 parts by weight of a polycarbonate resin having the structural unit represented by the structural formula (1-1) was used, and the binder resin for the structural formula (2-
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the polycarbonate resin having the structural unit shown in 1) was used as 120 parts by weight.

(Example 5) In a binder resin for a charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (1-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 25,000 was used instead of the 000.

(Example 6) In the binder resin for the charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (1-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 75,000 was used in place of that of 5,000.

However, since the coating liquid for the charge transport layer became highly viscous and the film thickness was uneven, a polyethylene terephthalate film (aluminum-deposited polyethylene terephthalate film) was used as the conductive support instead of the drum-shaped support made of aluminum. Thickness of 100 μm), on which an intermediate layer, a charge generation layer,
After applying the charge transport layer with an applicator, it was dried to prepare an electrophotographic photoreceptor. The film thickness and drying conditions were the same as in Example 1. The produced electrophotographic photosensitive member was attached to a drum-shaped support having the same shape and size as those used in Example 1 to obtain an electrophotographic photosensitive member for evaluation.

Example 7 In a binder resin for a charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (1-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 30,000 was used in place of that of 000.

(Example 8) In the binder resin for the charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (2-1) was used, and a viscosity average molecular weight of 21,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the viscosity average molecular weight of 10,000 was used instead of the number of 500.

(Example 9) In the binder resin for the charge transport layer, a polycarbonate resin having the structural unit represented by the structural formula (2-1) was used, and the viscosity average molecular weight of 21,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the viscosity average molecular weight of 39,000 (PCZ400 manufactured by Mitsubishi Gas Chemical Co., Inc.) was used in place of the number of 500.

However, since the coating solution for the charge transport layer became highly viscous and the film thickness was uneven, a polyethylene terephthalate film (aluminum-deposited polyethylene terephthalate film was used as the conductive support instead of the drum-shaped support made of aluminum. Thickness of 100 μm), on which an intermediate layer, a charge generation layer,
After applying the charge transport layer with an applicator, it was dried to prepare an electrophotographic photoreceptor. The film thickness and drying conditions were the same as in Example 1. The produced electrophotographic photosensitive member was attached to a drum-shaped support having the same shape and size as those used in Example 1 to obtain an electrophotographic photosensitive member for evaluation.

Example 10 In the binder resin for the charge transport layer, a polycarbonate resin having the structural unit represented by the structural formula (2-1) was used, and the viscosity average molecular weight was 2
Instead of 1,500, viscosity average molecular weight 32,20
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that No. 0 (PCZ300 manufactured by Mitsubishi Gas Chemical Co., Inc.) was used.

(Example 11) As a charge transport material for a charge transport layer, instead of the butadiene compound represented by the structural formula (3-2), the styryl represented by the structural formula (4-8) shown in Table 6 was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the system compound was used.

Example 12 As a charge transport material for the charge transport layer, an amine represented by the structural formula (5-1) shown in Table 9 was used instead of the butadiene compound represented by the structural formula (3-2). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the system compound was used.

Example 13 As a charge transport material for the charge transport layer, 4-dibenzylamino-2-methylbenzaldehyde-1,1-diphenyl was used in place of the butadiene compound represented by the structural formula (3-2). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that hydrazone was used.

Example 14 7 parts by weight of titanium oxide (TTO55A manufactured by Ishihara Sangyo Co., Ltd.) and 13 parts by weight of copolymerized nylon resin (CM8000 manufactured by Toray Co., Ltd.) were mixed with 1 part of methyl alcohol.
In addition to a mixed solvent of 59 parts by weight and 106 parts by weight of 1,3-dioxolane, dispersion treatment was carried out for 8 hours with a paint shaker to prepare a coating liquid for the intermediate layer. Fill the coating tank with the prepared coating liquid for the intermediate layer, and the diameter of the conductive support is 30 m.
A drum-shaped support made of aluminum and having a total length of 322 mm was dipped, pulled up and naturally dried to form an intermediate layer having a film thickness of 1 μm.

Then, 8 parts by weight of oxotitanyl phthalocyanine as a charge generating material was added to 100 parts of tetrahydrofuran.
100 parts by weight of the butadiene compound represented by the structural formula (3-2) shown in Table 3 and the structural formula (1-
A viscosity average molecular weight of 50 having a structural unit represented by 1),
80 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 21,500 (PCZ200 manufactured by Mitsubishi Gas Chemical Co., Inc.) having a structural unit represented by the structural formula (2-1) shown in Table 2; 5 parts by weight of 2,6-bis-tert-butyl-4-methylphenol (Sumilyzer BHT manufactured by Sumitomo Chemical Co., Ltd.) and 1170 parts by weight of tetrahydrofuran were mixed and stirred to prepare a photosensitive layer coating solution. After coating the prepared photosensitive layer coating liquid on the previously provided intermediate layer in the same manner as the above-mentioned intermediate layer, 1
It was dried at 10 ° C. for 1 hour to form a photosensitive layer having a film thickness of 20 μm.

In this way, a single-layer type electrophotographic photosensitive member having the layer structure shown in FIG. 4 was produced.

Comparative Example 1 The same as Example 1 except that only 160 parts by weight of the modified polycarbonate resin having the structural unit represented by the following structural formula (6) was used as the binder resin for the charge transport layer. To produce an electrophotographic photoreceptor.

[0113]

[Chemical 10]

Comparative Example 2 160% by weight of a polycarbonate resin having a viscosity average molecular weight of 21,500 (PCZ200 manufactured by Mitsubishi Gas Chemical Company) having a structural unit represented by the structural formula (2-1) as a binder resin for the charge transport layer. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that only a part was used.

(Evaluation) The electrophotographic photosensitive members produced in the above Examples 1 to 14 and Comparative Examples 1 and 2 were used as a copying machine for evaluation in a commercially available copying machine equipped with a separating claw made of polyimide (manufactured by Sharp Corporation). AR-255S), the halftone image was confirmed, and the initial image characteristics were evaluated.

Further, the developing tank was taken out from the developing portion of the evaluation copying machine and replaced with a surface electrometer (Mode manufactured by Trek).
1344) is set and the surface potential V at the time of copying a white solid document is set.
0 and the surface potential VL at the time of copying a black solid document were measured to evaluate the electrical characteristics. With respect to the electrophotographic photosensitive member of Example 14, the polarities of charging and transfer were modified to be positively charged and measured.

Further, after copying 30,000 sheets of A4 paper, the halftone image was confirmed and the surface potential was measured in the same manner as in the initial stage, and the durability was evaluated from the change due to repeated use. Further, the amount of wear was obtained by measuring the film thickness of the photosensitive layer after repeated use.

As Comparative Example 3, the photoconductor of Example 1 was mounted on a commercially available copying machine (AR-255S, manufactured by Sharp Corporation) not equipped with a separating claw, and evaluated in the same manner as in Example 1. The results are shown in Table 11.

[0119]

[Table 11]

From Examples 1 to 14 and Comparative Examples 1 and 2, the electrophotographic photoreceptors of Examples had the above-mentioned general formula (1) in the photosensitive layer.
Since it contains a polycarbonate resin A having a structural unit represented by the following formula, it has excellent photosensitivity characteristics, characteristic stability in repeated use and mechanical durability as compared with Comparative Examples, and a separation claw for preventing improper separation of transfer paper. It was found that the photoreceptor surface was not scratched even after repeated use in an image forming apparatus equipped with. Specifically, in the photoconductor of Comparative Example 1 in which the polycarbonate resin A was not used, scratches due to friction with a blade, paper or the like frequently occurred on the photoconductor surface, and scratches due to the separating claws also occurred. Further, using only the polycarbonate resin B having the structural unit represented by the general formula (2),
The photoconductor of Comparative Example 2 in which the polycarbonate resin A was not used had low sensitivity, and a good image could not be obtained even if the image was adjusted.

In Example 2, since the polycarbonate resin B was not mixed, ozone or N
Although the portion exposed to Ox deteriorated and some image unevenness occurred, it was not a problem in actual use because it had recoverability.

In Example 5, since the viscosity average molecular weight of the polycarbonate resin A was small, the abrasion amount was slightly increased. In Example 8 in which the polycarbonate resin B had a small viscosity average molecular weight, the amount of wear was also slightly increased. Further, in Example 6, since the viscosity average molecular weight of the polycarbonate resin A was large, it was difficult to carry out dip coating when producing the photoreceptor. Similarly, in Example 9 in which the polycarbonate resin B had a large viscosity average molecular weight, dip coating was also difficult. In such a case, it is necessary to use applicator coating, spray coating or the like instead of dip coating with high production efficiency.

In Example 13, as the charge-transporting material, the butadiene-based compound represented by the general formula (3), the styryl-based compound represented by the general formula (4) or the amine-based compound represented by the general formula (5) was used. Since no compound was used, the sensitivity was slightly low and exposure adjustment was necessary.

The laminated type photoconductor of Example 1 is the same as that of Example 1.
It was found that the sensitivity was better than that of the single-layer type photosensitive member of No. 4.

In Comparative Example 3, since the measurement was carried out by the image forming apparatus which was not equipped with the separating claw, a jam occurred due to the separation failure of the transfer paper at a rate of about several copies per 1,000 copies. When the transfer paper wrapped around the photoconductor was removed to remove the jam, the photoconductor surface was scratched and the scratch appeared on the image.

[0126]

As described above, according to the present invention, when the photosensitive layer contains the polymer compound having the structural unit represented by the general formula (1), the structure is asymmetrical, so that crystallization occurs. It is difficult to improve production efficiency and has good surface smoothness, and since there are no bulky groups, it can be tightly packed to form a strong film when it is dried and dried from a solution, and it has excellent wear resistance and charge transport. Since it has excellent compatibility with materials, it does not deteriorate the electrical characteristics, and it has excellent photosensitivity characteristics, stability in repeated use, and mechanical durability even in the configuration using mechanical separation means. It is possible to provide an image forming apparatus and an image forming method which do not cause an image defect without causing a separation failure of a transfer target from the sheet.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of an electrophotographic photoreceptor having a laminated photosensitive layer in which a charge transport layer 6 is laminated on a charge generation layer 5.

FIG. 2 is a cross-sectional view schematically showing an example of an electrophotographic photoreceptor having a single-layer type photosensitive layer containing a charge generating material 2 and a charge transporting material 3 in the same layer.

3 is a sectional view schematically showing an example having an intermediate layer 8 in the electrophotographic photoreceptor of FIG.

4 is a sectional view schematically showing an example having an intermediate layer 8 in the electrophotographic photoreceptor of FIG.

FIG. 5 is a configuration diagram showing a schematic configuration of a laser printer 30 which is an image forming apparatus according to the present invention.

[Explanation of symbols]

1 Conductive support 2 Charge generation material 3 Charge transport materials 4,14 Photosensitive layer 5 Charge generation layer 6 Charge transport layer 7 Binder resin 8 Middle class 11 Electrophotographic photoreceptor 30 laser printer 31 Semiconductor laser 32 Contact charger 33 Developer 34 Contact transfer charger 35 fixer 36 cleaner 37 Separated nail 38 Transfer paper

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Tanaka             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Masaki Hashimoto             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Hiroshi Sugimura             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F-term (reference) 2H068 AA13 AA21 AA31 AA35 AA37                       BB26 BB52 FA01 FA30

Claims (3)

[Claims] 1. An image forming method of forming an image by charging a surface of an electrophotographic photosensitive member and transferring a developer developed on the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is on a conductive substrate. At least
The photosensitive layer containing a charge generating material, a charge transporting material and a binder resin as a surface layer, the binder resin containing a polymer compound having a structural unit represented by the following general formula (1), the electrophotography An image forming method comprising a step of separating a transfer-receiving member, to which a developer is transferred from a photosensitive member, from the surface of the electrophotographic photosensitive member by a mechanical separating means. [Chemical 1] (Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸
Each has a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or a substituent. Represents an optionally substituted aryl group. ) 2. The polymer compound has a viscosity average molecular weight of 3.
The image forming method according to claim 1, wherein the image forming method is 50,000 or more and 70,000 or less. 3. An image forming apparatus for forming an image by charging a surface of an electrophotographic photosensitive member and transferring a developer developed on the electrophotographic photosensitive member, wherein at least a charge generating material is formed on a conductive substrate. A photosensitive layer containing a charge transporting material and a binder resin as a surface layer, the binder resin being equipped with an electrophotographic photoreceptor containing a polymer compound having a structural unit represented by the following general formula (1): An image forming apparatus comprising: a mechanical separating unit that separates a transfer-receiving member, on which a developer is transferred from a photographic photosensitive member, from the surface of the electrophotographic photosensitive member. [Chemical 2] (Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸
Each has a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or a substituent. Represents an optionally substituted aryl group. )