JPH10207085A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor free from image defects due to cracking and having superior printing resistance in the case of use as a beltlike photoreceptor without deteriorating electrical characteristics and image quality by incorporating polycarbonate resin having specified repeating structural units into a binder resin in a photosensitive layer. SOLUTION: This electrophotographic photoreceptor has a photosensitive layer using a binder resin contg. polycarbonate resin having repeating structural units represented by the formula, wherein each of X1 -X4 and X'1 -X'4 is H, halogen or methyl. The polycarbonate resin is preferably contained in the surface of the photosensitive layer. The shock resistance of a coating film largely affecting printing resistance relates to the molecular motion of polycarbonate resin in the film, and when the polycarbonate resin has such molecular motion as to absorb and diffuse external shock which causes cracking, the shock resistance of the coating film is considerably improved. The polycarbontate resin having the repeating structural units in which combining groups are -CH2 - ensures superior printing resistance without deteriorating electrical characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor having excellent electrical and mechanical properties over a long period of time and excellent production stability.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely applied in fields such as copying machines, laser beam printers, and facsimile machines because of the advantage that high quality printing can be obtained at high speed. As a photoreceptor in the electrophotographic technology, a photoreceptor using an inorganic photoconductive material such as selenium, a selenium-tellurium alloy, a selenium-arsenic alloy, or cadmium sulfide has been widely known.

[0003] On the other hand, electrophotographic photoreceptors using organic photoconductive materials which are inexpensive and have excellent manufacturability and disposal properties compared with electrophotographic photoreceptors using these inorganic photoconductive materials have been actively studied. Have been done. Above all, a function-separated type organic laminated photoreceptor in which a charge generation layer that generates charges by exposure and a charge transport layer that transports charges are laminated, in terms of electrophotographic characteristics such as sensitivity, chargeability, and its repetition stability. Because of their superiority, various types have been proposed and put into practical use.

A single-layer type organic photoreceptor can be easily manufactured at low cost and has a system of positive charging, so that it generates less ozone and has good uniform charging properties as compared with negative charging. On the other hand, there is a problem that the electrical performance is inferior to that of the laminated photoreceptor, and there is still room for research and development.

[0005] Among the above-mentioned organic laminated photoreceptors, those having sufficient electrophotographic properties have been developed. However, since the photosensitive layer is made of an organic material, the photoreceptor has high durability against mechanical external force. That is, abrasion or scratches on the surface of the photoreceptor due to a direct load from toner, developer, paper, a cleaning member, etc., image quality defects due to adhesion of foreign matter such as toner filming, or corona discharge. There is a problem such as the occurrence of image deletion in a high humidity environment caused by low resistance substances such as ozone and nitrogen oxides and paper powder from copying machines adhering and accumulating on the surface of the photoreceptor. Life is shortened.

[0006] Further, with the increasing colorization and speeding of copiers and printers, the electrophotographic process has become more complicated and higher in stress, and in view of these points, photoconductors having even higher durability have been developed. Has been requested. Furthermore, a flexible electrophotographic photoreceptor in which a conductive layer is formed on a film of polyethylene terephthalate or the like by vapor deposition or the like, and a coating of a photosensitive layer is formed thereon, is processed into an endless belt shape, and is processed in a copying machine. It has the advantage of having a large degree of freedom in the shape design of the copier because it can be used repeatedly, but for that purpose the photosensitive layer has the same flexibility as the film and follows the movement used in the copier sufficiently. It must do something.

Hitherto, in such an electrophotographic photoreceptor, those using various polycarbonate resins as a binder resin for a photosensitive layer have been proposed (for example, Japanese Patent Application Laid-Open No. Sho 60/1985).
172,044, JP-A-62-247374, JP-A-63-148263, JP-A 2-25
No. 4458, Japanese Unexamined Patent Application Publication No. 2-254449, Japanese Unexamined Patent Application Publication No. 3-63651, Japanese Unexamined Patent Application Publication No. 3-273256, Japanese Unexamined Patent Application Publication No. 4-37859, Japanese Unexamined Patent Application Publication No. 50-165.
No. 38, JP-A-54-24027, JP-A-6-24027
JP-A-3-148263, JP-A-1-206348, JP-A-4-19667), and, for example, a polycarbonate resin having a repeating structural unit represented by the following general formula (A ') has been proposed. .

[0008]

Embedded image (Where Z ₁ , Z ₁ ′, Z ₂ , Z ₂ ′, Z ₃ , Z ₃ ′,
Z ₄ and Z ₄ ′ may be the same or different and each represent a hydrogen atom, a halogen atom or an alkyl group, a cycloalkyl group or an aryl group, X represents a single bond, —O
-, - S -, - SO -, - SO 2 - or -C (Y ₁₎
(Y ₂ ) —, Y ₁ and Y ₂ may be the same or different and each represent a hydrogen atom, an alkyl group, or an aromatic group, and Y ₁ and Y ₂ together form a cyclic structure It may be formed. )

[0009]

However, when the above-mentioned polycarbonate resins proposed so far are used as a binder resin for a photosensitive layer, an electrophotographic photosensitive member having relatively good durability can be obtained, but it is still satisfactory. Not something. That is, the photosensitive layer composed of a coating film formed using the resin specifically disclosed in the above publication does not necessarily have sufficient mechanical strength, and when used repeatedly for a long time in a copying machine, the surface thereof has Is worn and the thickness of the photoreceptor changes, and the charging potential decreases with the change in sensitivity.
There is a problem that the image background portion is stained and the image density is reduced, and there is a problem that an image defect due to abrasion is generated on the surface of the photoconductor.

Therefore, when a resin with little wear is used as the binder resin, the electric characteristics are not sufficient, and there is a problem that an image defect occurs due to adhesion of foreign matter such as toner. In particular, in the case of a belt-shaped photoreceptor, when it is repeatedly rotated by a belt-shaped photoreceptor driving device in a copying machine, it cannot sufficiently cope with its flexible movement, and cracks occur in the photosensitive layer, which causes cracks on an image. There is also a problem that it appears as a pattern. Furthermore, the photosensitive layer is composed of a binder resin and a charge transport material, and the compatibility of the binder resin with the charge transport material is important. If the compatibility is low, some of the charge transport material is crystallized. It is known that the deposition and precipitation have a significant adverse effect on electrical characteristics and image quality, but conventional resins are insufficient in this compatibility.

The present invention has been made in view of the above-mentioned circumstances in the prior art. That is, an object of the present invention is to provide a coating film on the surface of a photoreceptor having high flexibility strength, to prevent the occurrence of defects such as cracks in the coating film due to repeated use as a belt-shaped photoreceptor, and to achieve high printing durability. An object of the present invention is to provide an electrophotographic photoreceptor which exhibits excellent electrical characteristics inherent to a charge transport material and can form excellent images for a long period of time.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the materials constituting the photosensitive layer, and as a result, as a binder resin, the repeating unit represented by the above-mentioned general formula (A ') conventionally proposed. Of the polycarbonate resins having a structural unit, when a polycarbonate resin having a specific repeating structural unit is selected and used, without deteriorating electrical characteristics and image quality, and when used for a belt-shaped photoconductor,
The present inventors have found that a photoconductor having excellent printing durability without any image defects due to the occurrence of cracks can be obtained, and the present invention has been completed.

That is, the electrophotographic photoreceptor of the present invention has a photosensitive layer provided on a conductive support, and the binder resin in the photosensitive layer has a repeating structure represented by the following general formula (A). It is characterized by containing a polycarbonate resin having units.

[0014]

Embedded image (Where X ₁ , X ₁ ′, X ₂ , X ₂ ′, X ₃ , X ₃ ′,
X ₄ and X ₄ ′ may be the same or different and each represents a hydrogen atom, a halogen atom or a methyl group. )

The polycarbonate resin of the present invention comprises a repeating structural unit represented by the above general formula (A), a repeating structural unit represented by the above general formula (A), and a resin represented by the following general formula (B). What consists of a polycarbonate copolymer which has a repeating structural unit which is used is preferably used.

[0016]

Embedded image (Wherein X ₅ , X ₅ ′, X ₆ and X ₆ ′ may be the same or different and each represent a hydrogen atom, a halogen atom or a methyl group, and Z represents —C (R ₁ ) (R ₁ ′) )-,
Or represents a cycloalkylidene group having 5 to 11 carbon atoms,
R ₁ and R ₁ 'may be the same or different and each represents a hydrogen atom or a methyl group. )

In the present invention, as the charge transporting material for the photosensitive layer, at least one of a triarylamine compound represented by the following general formula (C) or a benzidine compound represented by the following general formula (D) is used. It is preferred to contain.

Embedded image (Wherein R ₂ represents a hydrogen atom or a methyl group, and Ar ₁
And Ar ₂ represent a halogen atom, an alkyl group, an alkoxy group or an aryl group or a thienyl group which may be substituted by a substituted amino group, respectively. n is 1 or 2. )

[0018]

Embedded image (Wherein R ₃ and R ₃ ′ may be the same or different and each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₄ , R ₄ ′, R ₅ and R ₅ ′ may be the same or different. Which may be different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a substituted amino group; k, k ', l and l' are each 1 or 2)

In the present invention, the polycarbonate resin or the polycarbonate copolymer is preferably contained on the outermost surface of the photosensitive layer. Repeating structural units of formula (A) in the present invention, conventional, 'is a known as part of the general formula (A above general formula (A)' X in) is -CH ₂ - represents a In this case, unlike other cases, the printing durability is particularly excellent. In other words, according to the findings from molecular simulations and high-resolution nuclear magnetic resonance measurements, the impact resistance of the coating film, which greatly affects the printing durability, is related to the molecular mobility of the polycarbonate resin and causes external cracks that cause cracks. When the polycarbonate resin has a molecular mobility capable of absorbing and dissipating an impact force, the impact resistance is significantly improved. In particular, the mobility of the main chain skeleton greatly contributes to the molecular mobility of the polycarbonate resin, and depends on the size of X. If X is too large, the motility of the main chain skeleton is impaired, and the impact resistance decreases. Further, when X represents —CH ₂ —, the adjacent aryl group must also have a size and weight that do not inhibit the mobility of the main chain skeleton. When X has a highly polar atom such as -O- or -SO-, the molecular mobility does not decrease due to the size and weight, but the charge transport property of the charge transport material depends on the polarity. And adversely affect electrical characteristics. Therefore, among the repeating structural units represented by the above general formula (A '), the polycarbonate resin having the repeating structural unit represented by the above general formula (A) in the present invention can be used without any deterioration in electrical properties. It has excellent printing durability.

[0020]

Embodiments of the present invention will be described below in detail. First, the layer structure of the electrophotographic photoreceptor of the present invention will be described with reference to the drawings. FIGS. 1 to 4 are schematic cross-sectional views each showing an example of a layer configuration of an electrophotographic photoconductor in which a photosensitive layer has a laminated structure in the present invention. FIG. 1 shows a photoconductor having the simplest layer configuration among the stacked photoconductors. A charge generation layer 1 and a charge transport layer 2 are sequentially formed on a conductive support 3. In FIG. 2, an undercoat layer 4 is provided between the conductive support 3 having the layer configuration of FIG. 1 and the charge generation layer 1. In FIG. 3, a protective layer 5 is provided on the surface of the layer configuration of FIG. 4, a protective layer 5 is provided on the surface of the layer configuration of FIG. 5 and 6 are schematic cross-sectional views showing examples of the layer structure of an electrophotographic photosensitive member in which the photosensitive layer according to the invention has a single-layer structure. FIG. 5 shows that the photoconductive layer 6 is formed on the conductive support 3. FIG. 6 shows that the undercoat layer 4 and the photoconductive layer 6 are formed on the conductive support 3 in this order.

Next, each layer of the electrophotographic photosensitive member of the present invention will be described in detail. Examples of the conductive support include metals such as aluminum, nickel, chromium, and stainless steel, and aluminum, titanium, nickel, chromium,
Plastic films provided with thin films of stainless steel, gold, vanadium, tin oxide, indium oxide, ITO, etc.
And a paper or plastic film coated or impregnated with a conductivity-imparting agent. These conductive supports are used in an appropriate shape such as a cylindrical shape, a plate shape, a sheet shape, and an endless belt shape, but are not limited thereto. Furthermore, if necessary, the surface of the conductive support may be subjected to various treatments within a range that does not affect image quality, for example,
Irregular reflection treatment such as oxidation treatment, chemical treatment, coloring treatment, or graining of the surface can be performed.

In the present invention, it is desirable to provide an undercoat layer between the conductive support and the photosensitive layer. The undercoating layer prevents charge injection from the conductive support into the photosensitive layer during charging of the photosensitive layer, and also acts as an adhesive layer for integrally bonding and holding the photosensitive layer and the conductive support. Has an effect of preventing reflected light from the conductive support.

The materials used for the undercoat layer include the following. Polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polyurethane resin, melamine resin, benzoguanamine resin, polyimide resin, polyethylene resin, polypropylene resin, polycarbonate resin, acrylic resin, methacrylic resin, vinylidene chloride resin, polyvinyl acetal resin, chloride Vinyl-vinyl acetate copolymer, polyvinyl alcohol resin,
Water-soluble polyester resin, nitrocellulose, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, polyacrylamide, zirconium chelate compound, titanyl chelate compound, titanyl alkoxide compound, organic titanyl compound, silane coupling agent And other known materials. These materials can be used alone or in combination of two or more. Further, these materials may be mixed with titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, barium titanate, silicone resin, and the like.

The coating method for forming the undercoat layer includes:
Blade coating method, myrbar coating method,
Conventional methods such as spray coating, dip coating, bead coating, air knife coating, curtain coating, and die coating are employed. The thickness of the undercoat layer is in the range of 0.01 to 10 μm, preferably in the range of 0.05 to 2 μm.

In the electrophotographic photoreceptor of the present invention, the photosensitive layer formed on the conductive support may have a single layer structure or a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. It may be. When the photosensitive layer has a laminated structure, the charge generating layer and the charge transporting layer may be stacked in any order.

The photosensitive layer is composed of a coating film containing a charge generation material, a charge transport material, or both of them in a binder resin. In the present invention, a polycarbonate resin having a repeating structural unit represented by the general formula (A) in the binder resin of the photosensitive layer, specifically, a repeating unit represented by the general formula (A) It is necessary to include a polycarbonate resin or a polycarbonate copolymer comprising a repeating structural unit represented by the general formula (A) and a repeating structural unit represented by the general formula (B). It is preferable that the copolymer is contained in the outermost surface layer of the photosensitive layer in the invention. Hereinafter, the case where the photosensitive layer has a laminated structure and the charge transport layer is mainly an upper layer will be described.

The charge generation layer in the present invention can be formed by forming the charge generation material by vacuum evaporation or by applying a solution in which the charge generation material is dispersed in a binder resin in an organic solvent. As a charge generation material,
Amorphous selenium, crystalline selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and alloys, granular selenium, zinc oxide, inorganic photoconductive materials such as titanium oxide,
Organic pigments or dyes such as phthalocyanine, squarium, anthantrone, perylene, azo, anthraquinone, pyrene, pyrylium salts and thiapyrylium salts are used. Among these, a photoreceptor using a phthalocyanine pigment, particularly a metal-free phthalocyanine, titanyl phthalocyanine, or gallium phthalocyanine, is used in a near-infrared wavelength region (780 nm to 830 nm) of a semiconductor laser.
Has high sensitivity and long-term stable electrical characteristics. Specifically, the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα is at least 6.8.
Gallium phthalocyanine having strong diffraction peaks at °, 12.8 °, 15.8 ° and 26.0 °, the Bragg angle of the X-ray diffraction spectrum by CuKα (2θ ± 0.2
°) is at least 7.5 °, 9.9 °, 12.5 °,
16.3 °, 18.6 °, 25.1 ° and 28.3 °
Hydroxygallium phthalocyanine (see FIG. 7) having a strong diffraction peak, the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα is at least 7.
Chlorogallium phthalocyanine having strong diffraction peaks at 4 °, 16.6 °, 25.5 ° and 28.3 ° can be mentioned as a preferable example. Further, in the visible light wavelength region, an anthrone-based pigment has stable electrical properties over a long period of time, and granular selenium, particularly granular trigonal selenium, has stable electrical properties over a long period of time and has high sensitivity. It has the characteristic.

As the binder resin in the charge generation layer, polyvinyl butyral resin, polyvinyl formal resin,
Polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins modified with a part of butyral such as formal acetoacetal, polyamide resins, polyester resins, modified ether type polyester resins, polycarbonate resins, acrylic resins, polyvinyl chloride resins, Polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, silicone resin, phenol resin, phenoxy resin, melamine resin, benzoguanamine resin, urea resin,
Polyurethane resin, poly-N-vinyl carbazole resin, polyvinyl anthracene resin, polyvinyl pyrene and the like can be mentioned. Of these, polyvinyl acetal resins, vinyl chloride-vinyl acetate copolymers, phenoxy resins, and modified ether-type polyester resins are particularly preferred. These resins are capable of dispersing the phthalocyanine-based pigment, anthantrone-based pigment and granular trigonal selenium satisfactorily, and can provide a long-term stable dispersion coating solution without agglomeration of the pigment. By using the coating liquid, a uniform film is formed, and as a result, an image free from defects can be obtained with good electric characteristics. In addition, resins other than those described above can be used as long as they can form a coating in a normal state.

The compounding ratio of the charge generating material to the binder resin is preferably in the range of 5: 1 to 1: 2 by volume. Examples of the solvent used for preparing the coating liquid include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, chlorobenzene, methyl acetate, and n-butyl acetate. , Dioxane, tetrahydrofuran, methylene chloride, chloroform and the like, and commonly used organic solvents. These may be used alone or in combination of two or more. As a method of applying the coating liquid, a usual method such as a blade coating method, a myrbar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, a die coating method, etc. is adopted. You. The thickness of the charge generation layer is usually from 0.01 to 5 μm, preferably from 0.1 to 2.0 μm. If the thickness is less than 0.01 μm, it is difficult to form the charge generation layer uniformly, while 5 μm
If m exceeds m, the electrophotographic properties tend to be significantly reduced.

As the binder resin in the charge transport layer of the present invention, a polycarbonate resin having a repeating structural unit represented by the following general formula (A) is used. A polycarbonate resin comprising a repeating structural unit represented by the following formula, and a polycarbonate copolymer comprising a repeating structural unit represented by the following general formula (A) and a repeating structural unit represented by the above general formula (B) are used.

[0031]

Embedded image (Where X ₁ , X ₁ ′, X ₂ , X ₂ ′, X ₃ , X ₃ ′,
X ₄ , X ₄ ′, X ₅ , X ₅ ′, X ₆ , X ₆ ′ and Z
Has the same meaning as described above. In the above formula, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and a methyl group is particularly preferable. Examples of the cyclo ring of the cycloalkylene group and the cycloalkylidene group include cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and cycloundecane, with cyclopentane, cyclohexane and cycloheptane being particularly preferred.

As the polycarbonate resin used in the present invention, a resin having at least one repeating structural unit selected from the following structural formulas (A-1) to (A-63) is preferable.

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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The polycarbonate copolymer used in the present invention has a repeating structural unit represented by the general formula (A) and a repeating structural unit selected from the following formulas (B-1) to (B-3). Are preferred.

[0044]

Embedded image

In the case of a polycarbonate copolymer comprising a repeating structural unit represented by the above general formula (A) and the above general formula (B), the repeating structural unit represented by the general formula (A) is 5 mol% or more. It is necessary to include it. When the repeating structural unit represented by the general formula (A) is less than 5 mol%, the wear resistance becomes insufficient and the amount of wear increases,
Significant image defects occur.

The polycarbonate resin and the polycarbonate copolymer used in the present invention have a viscosity average molecular weight of 10,000 to 200,000, preferably 20,000 to 100,000, and have a relatively uniform molecular weight distribution. Are preferred.
If the viscosity average molecular weight is less than 10,000, the required film thickness cannot be obtained due to the low viscosity of the coating solution, and if the viscosity average molecular weight is less than 10,000 to 20,000, the film can be obtained by dip coating. Thickness unevenness may occur, and the mechanical strength and abrasion resistance of the formed coating film may be insufficient. On the other hand, when the molecular weight is 200,000 or more, the viscosity of the coating solution is too high, and it is difficult to control the thickness to a required thickness, and a uniform coating film cannot be obtained. However, even in the case of a polycarbonate resin having a viscosity average molecular weight other than the above range, the viscosity average molecular weight is in the range of 20,000 to 200,000 by appropriately mixing and using the above polycarbonate resin or polycarbonate copolymer. Can improve the problem. Further, as long as the function and effect obtained by using the polycarbonate resin and the polycarbonate copolymer are not impaired, a mixture with a different kind of polycarbonate resin or a copolymer thereof can be used.

In the present invention, at least one of a triarylamine compound represented by the following general formula (C) or a benzidine compound represented by the following general formula (D) is used as a charge transporting material of the charge transporting layer. It is desirable to do.

[0048]

Embedded image (Wherein R ₂ represents a hydrogen atom or a methyl group, R ₃ and R ₃ ′ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₄ , R ₄ ', R ₅ and R ₅ ' may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a substituted amino group;
Ar ₁ and Ar ₂ each represent a halogen atom, an alkyl group, an alkoxy group or an aryl group or a thienyl group which may be substituted by a substituted amino group. n,
k, k ', l and l' are each 1 or 2. Specific examples of the triarylamine-based compound include those shown in Tables 1 to 3 below, but are not limited thereto. These may be used alone or in combination of two or more.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

Further, specific examples of the benzidine-based compound include those shown in Tables 4 to 6 below, but are not limited thereto. These may be used alone or in combination of two or more.

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6] In Tables 4 to 6, only benzidine-based compounds in which R ₃ and R ₃ ′, R ₄ and R ₄ ′, and R ₅ and R ₅ ′ are the same are described. They are not necessarily the same, and furthermore, R ₃ ′, R ₄ ′, and R ₃ ′
The substitution position of ₅ 'also may not be the same as R _3, R ₄ and R _5.

In the charge transporting layer of the electrophotographic photoreceptor of the present invention, the composition ratio of the charge transporting material to the binder resin is preferably in the range of 10:90 to 70:30 by weight, and particularly preferably 3: 3.
The range of 0:70 to 60:40 is preferred.

Further, solvents used for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and xylene; halogenated aromatic hydrocarbons such as chlorobenzene; ketones such as acetone and methyl ethyl ketone; Commonly used organic solvents such as halogenated aliphatic hydrocarbons such as methylene, chloroform, ethylene chloride and the like, and cyclic or linear ethers such as tetrahydrofuran and ethyl ether can be mentioned.
A mixture of more than one species can be used. As a coating method, a usual method such as a blade coating method, a myrbar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, and a die coating method is employed.

In the present invention, the thickness of the charge transport layer is usually set in the range of 5 to 70 μm, preferably in the range of 10 to 50 μm. If the film thickness is less than 5 μm, the initial charging potential tends to be low, and if it exceeds 70 μm, the electrophotographic characteristics and image quality tend to deteriorate.

For the purpose of preventing the deterioration of the electrophotographic photosensitive member due to ozone or oxidizing gas generated in the copying machine, or light or heat, an antioxidant, a stabilizer, a heat stabilizer and the like are contained in the photosensitive layer. Can be added. For example, as the antioxidant, hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, organic phosphorus compounds and the like are used. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperazine.

When the photosensitive layer of the electrophotographic photosensitive member of the present invention has a single-layer structure, the same charge-generating material and charge-transporting material as those used when the photosensitive layer has a laminated structure are used. The polycarbonate resin or the polycarbonate copolymer described in the description of the charge transport layer is used as the binder resin. In the polycarbonate resin, the other binder resin exemplified in the charge generation layer may be used.
It can be contained in a range of less than 0% by weight. Further, if necessary, additives such as the above-described antioxidants, light stabilizers, and heat stabilizers can be included in the photosensitive layer.

In the single-layer type photoreceptor, the content of the charge generating material is based on the total amount of the charge transporting material and the binder resin.
0.1 to 20% by weight, preferably 0.5 to 20% by weight.
5% by weight is suitable. The composition ratio of the charge transport material and the binder resin is preferably in the range of 60:40 to 30:70 by weight. The thickness of the single-layer type photoreceptor is usually in the range of 5 to 70 μm, preferably in the range of 10 to 40 μm.

In the electrophotographic photoreceptor of the present invention, it is preferable that the above-mentioned polycarbonate resin or polycarbonate copolymer is contained as a binder resin used on the outermost surface of the photosensitive layer, so that electrical characteristics and image quality can be reduced. It is possible to obtain a photoreceptor having excellent printing durability without lowering, and having no image quality defect accompanied by cracks as a belt-shaped photoreceptor. Further, a protective layer may be formed on the charge transporting layer in the case of a laminated type photoreceptor and on the photosensitive layer in the case of a single layer type photoreceptor.

[0062]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The “parts” in Examples and Comparative Examples
Means parts by weight. Example 1 A zirconium compound (trade name: Organix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) 1 on an aluminum cylindrical substrate
A solution consisting of 0 parts, 1 part of a silane compound (trade name: A1110, manufactured by Nippon Unicar), 40 parts of isopropanol and 20 parts of butanol is applied by a dip coating method,
Heat and dry at 150 ° C for 10 minutes to a film thickness of 0.1μ
m was formed. Next, as a charge generation material, 1 part of hydroxygallium phthalocyanine having an X-ray diffraction spectrum shown in FIG.
A mixture consisting of 1 part of a vinyl acetate copolymer (trade name: VMCH, manufactured by Union Carbide Co.) and 100 parts of chlorobenzene was subjected to dispersion treatment with glass beads for 1 hour by a sand mill, and the obtained coating solution was placed on the undercoat layer. The composition was applied by a dip coating method and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.25 μm.

Next, 12 parts of a polycarbonate resin having a repeating structural unit represented by the formula (A-1) (viscosity average molecular weight of 40,500), and a triarylamine-based compound (exemplified compound C-28) as a charge transport material And 8 parts of these were dissolved in 100 parts of monochlorobenzene, and the resulting coating solution was applied on the above-mentioned charge generating layer.
Heat and dry at 15 ° C. for 60 minutes to obtain a film thickness of about 20 μm.
An electrophotographic photoreceptor was prepared by forming a m charge transport layer.

Comparative Example 1 In Example 1, a polycarbonate resin (viscosity average molecular weight 44,700) comprising a repeating structural unit represented by the following formula (A'-1) was used instead of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the photoreceptor was used.

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Comparative Example 2 In Example 1, a polycarbonate resin (viscosity average molecular weight 42,600) having a repeating structural unit represented by the following formula (A'-2) was used instead of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the photoreceptor was used.

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Comparative Example 3 In Example 1, a polycarbonate resin (viscosity average molecular weight: 40,000) comprising a repeating structural unit represented by the following formula (A'-3) was used instead of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the photoreceptor was used.

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Example 2 In Example 1, the repeating structural unit represented by the formula (A-1) and the repeating structural unit represented by the formula (B-1) were used instead of the polycarbonate resin used for the charge transport layer. Electrophotographic photosensitive material was prepared in the same manner as in Example 1 except that a polycarbonate copolymer consisting of: (viscosity average molecular weight 43,100, molar ratio of (A-1) :( B-1) was 1: 1) was used. The body was made.

Example 3 In Example 1, a polycarbonate resin having a repeating structural unit represented by the formula (A-28) (viscosity average molecular weight 44,000) was used in place of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was produced in the same manner as in Example 1 except for the fact that the electrophotographic photosensitive member was not used.

Comparative Example 4 In Example 3, a polycarbonate resin having a repeating structural unit represented by the following formula (A'-4) (viscosity average molecular weight 47,700) was used instead of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner as in Example 3, except for using the same.

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Example 4 In Example 2, the repeating unit represented by the formula (A-55) and the repeating unit represented by the formula (B-2) were used instead of the polycarbonate copolymer used for the charge transport layer. The same procedure as in Example 2 was repeated except that a polycarbonate copolymer having a structural unit (viscosity average molecular weight 39,900, molar ratio of (A-55) :( B-2) was 1: 9) was used. A photoreceptor was prepared.

Comparative Example 5 In Example 4, instead of the polycarbonate copolymer used for the charge transport layer, a repeating structural unit represented by the following formula (A'-1) and a repeating structural unit represented by the following formula (B'-1) were used. Copolymer having a repeating structural unit (viscosity average molecular weight 45,900, (A'-1): (B'-
Example 2 except that the molar ratio of 1) was 1: 9).
An electrophotographic photoreceptor was produced in the same manner as described above.

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Comparative Example 6 In Example 1, a polycarbonate resin (viscosity average molecular weight 39,400) comprising a repeating structural unit represented by the following formula (A'-5) was used instead of the polycarbonate resin used for the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the photoreceptor was used.

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Example 5 In Example 2, the repeating unit represented by the formula (A-60) and the repeating unit represented by the formula (B-1) were used instead of the polycarbonate copolymer used for the charge transport layer. The same procedure as in Example 2 was repeated except that a polycarbonate copolymer composed of structural units (viscosity average molecular weight: 48,700, the molar ratio of (A-60) :( B-1) was 7: 3) was used. A photoreceptor was prepared.

Example 6 In Example 2, the repeating unit represented by the formula (A-60) and the repeating unit represented by the formula (B-3) were used in place of the polycarbonate copolymer used for the charge transport layer. The same procedure as in Example 2 was repeated except that a polycarbonate copolymer composed of structural units (viscosity average molecular weight: 41,600, molar ratio of (A-60) :( B-3) was 7: 3) was used. A photoreceptor was prepared.

Examples 7 to 9 In Example 5, the repeating unit represented by the formula (A-60) and the compound represented by the formula (B-1) were used in place of the polycarbonate copolymer used for the charge transport layer. The molar ratio of the polycarbonate copolymer composed of repeating structural units is 5:95 (viscosity average molecular weight is 40,80).
0), 1: 1 (viscosity average molecular weight of 44,100), 9
An electrophotographic photoreceptor was prepared in the same manner as in Example 5, except that a polycarbonate copolymer having a 5: 5 (viscosity average molecular weight of 47,200) was used.

Examples 10 to 12 In Example 1, the above-mentioned formula (A-
Instead of the polycarbonate resin having a viscosity average molecular weight of 40,500 composed of the repeating structural unit shown in 1), the viscosity average molecular weight is 20,300, 59,100,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a polycarbonate resin of 80,000 was used.

Examples 13 to 16 In Example 1, instead of the polycarbonate resin used for the charge transport layer, a polycarbonate resin comprising a repeating structural unit represented by the above formula (A-9) (having a viscosity average molecular weight of 46,300 ), And in place of the charge transporting material (exemplified compound C-28) in the charge transporting layer, an amine compound (compound C-4 shown above) or a benzidine-based compound (the above exemplified compounds D-10 and D-23, respectively) Or an electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that D-49) was used.

Example 17 Example 1 was repeated, except that an aluminum-clad polyethylene terephthalate film was used as the conductive support in place of the aluminum cylindrical substrate, and the die coating method was used instead of the dip coating method. In the same manner as in the above, an endless belt-shaped electrophotographic photosensitive member was produced.

Comparative Example 7 Example 1 was repeated except that the polycarbonate resin used in Comparative Example 2 was used in place of the polycarbonate resin used in the charge transport layer in Example 1.
An endless belt-shaped electrophotographic photosensitive member was produced in the same manner as in No. 7.

Each of the electrophotographic photosensitive members obtained in each of the above Examples and Comparative Examples was mounted on a laser beam printer (trade name: XP-15, manufactured by Fuji Xerox Co., Ltd.), and the temperature was adjusted to 20 ° C. and 45% RH. A print running test was performed on up to 100,000 sheets in an environment, and the abrasion amount of the photoreceptor surface before and after the copying was measured, and the obtained image quality was evaluated. Table 7 shows the results.

[0081]

[Table 7]

As is clear from the results in Table 7, when an image is formed using the electrophotographic photosensitive member of the present invention, a stable image quality can be obtained for a long period of time. When the polycarbonate copolymer of the present invention is used as the binder resin of the photosensitive layer, when the content of the repeating structural unit represented by the general formula (A) is 5 mol% (Example 7), the amount of abrasion increases. As a result, some image defects occurred, but they were extremely minor and did not pose a problem.
However, when the content of the repeating structural unit represented by the general formula (A) is less than 5 mol%, the amount of wear further increases,
It has been found that the degree of image defects increases as a problem. Therefore, when a polycarbonate copolymer is used as the binder resin, the content of the repeating structural unit represented by the general formula (A) is preferably at least 5 mol%.

When the polycarbonate resin has a viscosity-average molecular weight of 20,300, an image defect occurs in a very small part with an increase in abrasion amount. However, the defect is small and has few problems. However, it was found that when the viscosity average molecular weight was less than 20,000, the abrasion amount further increased, and the degree of image defects became so large that it became a problem. Therefore, the polycarbonate resin used as the binder resin preferably has a viscosity average molecular weight of 20,000 or more.

[0084]

The electrophotographic photoreceptor of the present invention contains a specific polycarbonate resin having a repeating structural unit represented by the general formula (A) as a binder resin for the photosensitive layer, thereby providing mechanical and electrical properties. In particular, wear resistance and corona discharge resistance are dramatically improved. Further, the repeating unit represented by the general formula (A) and the general formula (B) are added to the photosensitive layer.
When a polycarbonate copolymer having a repeating structural unit represented by is used as a binder resin and a charge transport material comprising a specific triarylamine-based compound or a specific benzidine-based compound is used in combination, the abrasion resistance and the It can maintain high toner filming resistance without lowering corona discharge property, and does not cause problems in the photosensitive layer even when used repeatedly for a long time in copiers, printers, etc. The characteristics do not deteriorate. That is, the electrophotographic photoreceptor of the present invention has high printing durability in which a copied image having excellent image quality can be obtained over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a layer configuration example of an electrophotographic photoreceptor of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating another example of the layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating another example of the layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a schematic cross-sectional view illustrating another example of a layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a schematic cross-sectional view illustrating another example of a layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 6 is a schematic cross-sectional view illustrating another example of the layer configuration of the electrophotographic photosensitive member of the present invention.

FIG. 7 is a powder X-ray diffraction spectrum of hydroxygallium phthalocyanine used in Examples.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Charge generation layer, 2 ... Charge transport layer, 3 ... Conductive support,
4 ... undercoat layer, 5 ... protective layer, 6 ... photoconductive layer.

Claims (8)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer provided on a conductive support, wherein the photosensitive layer contains, as a binder resin, a polycarbonate resin having a repeating structural unit represented by the following general formula (A). An electrophotographic photoreceptor characterized in that: Embedded image (Where X ₁ , X ₁ ′, X ₂ , X ₂ ′, X ₃ , X ₃ ′,
X ₄ and X ₄ ′ may be the same or different and each represents a hydrogen atom, a halogen atom or a methyl group. ) 2. The binder resin is a polycarbonate copolymer comprising a repeating structural unit represented by the general formula (A) and a repeating structural unit represented by the following general formula (B). 2. The electrophotographic photosensitive member according to 1. Embedded image (Wherein X ₅ , X ₅ ′, X ₆ and X ₆ ′ may be the same or different and each represent a hydrogen atom, a halogen atom or a methyl group, and Z represents —C (R ₁ ) (R ₁ ′) )-,
Or represents a cycloalkylidene group having 5 to 11 carbon atoms,
R ₁ and R ₁ 'may be the same or different and each represents a hydrogen atom or a methyl group. ) 3. The polycarbonate resin contains 5 to 100 mol% of a repeating structural unit represented by the general formula (A).
The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor has the following range. 4. The repeating structural unit represented by the general formula (A) is represented by the following formulas (A-1), (A-9), (A-28),
4. The electrophotographic photoreceptor according to claim 1, comprising at least one selected from (A-55) and (A-60). Embedded image 5. The repeating structural unit represented by the general formula (B) is selected from the following formulas (B-1) to (B-3). The electrophotographic photosensitive member according to any one of the above. Embedded image 6. The photosensitive layer according to claim 1, wherein the charge transporting material contains at least one triarylamine compound represented by the following general formula (C).
The electrophotographic photosensitive member according to any one of the above. Embedded image (Wherein R ₂ represents a hydrogen atom or a methyl group, and Ar ₁
And Ar ₂ represent a halogen atom, an alkyl group, an alkoxy group or an aryl group or a thienyl group which may be substituted by a substituted amino group, respectively. n is 1 or 2. ) 7. The electron according to claim 1, wherein the photosensitive layer contains at least one benzidine compound represented by the following general formula (D) as a charge transport material. Photoreceptor. Embedded image (Wherein R ₃ and R ₃ ′ may be the same or different and each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₄ , R ₄ ′, R ₅ and R ₅ ′ may be the same or different. Which may be different and each represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a substituted amino group; k, k ', l and l' are each 1 or 2) 8. A polycarbonate resin having a repeating structural unit represented by the general formula (A) on the outermost surface of the photosensitive layer, or a repeating structural unit represented by the general formula (A) and a general formula (B) The electrophotographic photoreceptor according to any one of claims 1 to 7, further comprising a polycarbonate copolymer comprising a repeating structural unit.