JP3407491B2 - Electrophotographic photoreceptor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member having excellent electrical characteristics and mechanical strength over a long period of time and having excellent manufacturing stability.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has the advantage that high speed and high print quality can be obtained.
It is remarkably widely applied in the fields of laser beam printers and facsimiles. As electrophotographic photoreceptors used in these electrophotographic techniques, those using inorganic photoconductive materials such as selenium, selenium-tellurium alloys, selenium-arsenic alloys, and cadmium sulfide have been widely known. On the other hand, as compared with electrophotographic photoreceptors using these inorganic photoconductive materials, research on electrophotographic photoreceptors using organic photoconductive materials, which are cheaper and have excellent advantages in terms of manufacturability and disposal, has also been activated. There is. Among them, the function-separated organic laminate type photoreceptor in which a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges is laminated is
It is excellent in electrophotographic properties such as chargeability and its repeated stability, and various proposals have been made and put to practical use. On the other hand, the single-layer type organic photoconductor has manufacturability, production cost, and positive charging system advantages (reduction of ozone generation, uniform charging property), while electric performance is higher than that of the laminated photoconductor. However, there is still plenty of room for research and development.

Although the above-mentioned organic photoreceptor has been developed to have sufficient performance with respect to the above electrophotographic characteristics, it is inferior in durability against mechanical external force because it is made of an organic material. That is, the organic photosensitive member has a problem that abrasion, scratches or the like on the surface of the photosensitive member due to a direct load from a toner, a developer, a paper, a cleaning member, or recently a roll or the like which directly contacts and charges the photosensitive member, Also, there is a problem that image quality defects occur due to foreign matter such as toner filming and the like, and further deterioration of the surface layer due to ozone or nitrogen oxides generated by corona discharge, paper dust generated from copy paper, etc. There is a problem such as image deletion in a high humidity environment caused by adhesion and accumulation on the surface of the photoconductor, and these problems regulate the life of the photoconductor.

Further, by digitizing a copying machine or a printer, since exposure is performed by using a semiconductor laser, the sensitivity of the photosensitive wavelength range of the photoconductor is maximized in the near infrared semiconductor laser wavelength range (780 to 830 nm). With devising, colorization, speeding up, and miniaturization, the process of charging-exposure-developing-transfer-cleaning-static elimination tends to be performed in a shorter time, resulting in faster photoresponsiveness and long-term Electrical stability has been demanded. As described above, higher durability is required from the viewpoints of increasing the complexity of these processes and increasing stress.
Various materials have been conventionally studied for the binder resin of the photosensitive layer in these electrophotographic photoreceptors, and for example, it has been proposed to use various modified polycarbonate resins as the binder resin of the photoreceptor surface layer ( JP 60-1
72044, JP-A-62-247374,
JP-A-63-148263, JP-A-1-17775
51, JP-A-2-254458, JP-A-2
-254459, JP-A-3-63651,
JP-A-3-150571, JP-A-4-17996
No. 1, Japanese Patent Publication No. 5-3584, Japanese Patent Laid-Open No. 5-80
548, JP-A-5-142800).

[0005]

However, when the conventionally proposed resin is used as the binder resin for the photosensitive layer, a relatively good durability of the electrophotographic photoreceptor can be obtained, but it is still satisfactory. There was no. That is, the mechanical strength of a coating film formed using such a resin is not always sufficient, and when it is repeatedly used in a copying machine for a long period of time, the surface of the photosensitive layer is abraded and Since the film thickness of the body changes, the charging potential decreases, and the sensitivity changes, fog occurs in the copy or the copy density decreases. In addition, an image quality defect occurs due to a scratch on the surface of the photoconductor. On the other hand, when a resin that is less worn is used, the electrical characteristics are not sufficient, and when the resin is not scraped off, there arises a problem that an image quality defect occurs due to adhesion of foreign matter such as toner filming. When forming the photosensitive layer,
When a binder resin that is soluble only in a low boiling organic solvent such as methylene chloride or tetrahydrofuran is used, a phenomenon that the coating surface takes in water in the air to whiten during coating, that is, a brushing phenomenon, or There is a problem that the surface may cause citrus-like irregularities. In order to solve these problems, an organic solvent having a high boiling point can be mixed, but this causes a problem that the coating solution is gelated at an early stage and the production stability is lowered.

The compatibility of the charge transport material with the binder resin is also important, and if the compatibility is low, some charge transport materials may cause crystallization, precipitation, etc., which significantly affects electrical characteristics and image quality characteristics. It has been known. Japanese Patent Fair 5-3584
Even when the compatibility is good as in the case of the copolycarbonate described in JP-A No. 1993-242945, when the charge transport layer is formed by combining it with a benzidine-based charge transport material, there is a problem that the discharge product generated at the time of charging causes deterioration of image quality. Yes,
Further, in an electrophotographic apparatus of a high speed process which employs a drum having a smaller diameter, further improvement in electrical characteristics is desired.

The present invention has been made in view of the above problems in the prior art. That is, the object of the present invention is high in abrasion resistance, corona discharge resistance, toner filming resistance, and excellent in electrical characteristics and image quality maintenance,
An object is to provide an electrophotographic photosensitive member that can be repeatedly used for a long period of time.

[0008]

Means for Solving the Problems As a result of earnest studies on the material of the photosensitive layer, the present inventors have found that at least one specific polyarylate resin is contained as a binder resin, and further, a charge transport material. By containing at least one triarylamine-based compound as
The present invention has been completed by finding that the manufacturability, the electrical characteristics and the image quality maintaining ability are improved to further improve the abrasion resistance.

That is, according to the present invention, in the electrophotographic photoreceptor having a photosensitive layer provided on a conductive support, the outermost surface of the photosensitive layer is represented by the following general formula (I) or (II) as a binder resin. Viscosity average molecular weight consisting of repeating structural units of 10,000
It is a charge transport layer containing at least one polyarylate resin of about 200,000 . In particular, it is characterized by containing at least one triarylamine compound represented by the following general formula (III) as a charge transport material for the photosensitive layer.

[0010]

[Chemical 6] (Wherein, X and X 'are hydrogen atoms frame other represents a methyl group, Y and Y' Represents a methyl group or a phenyl group,
A ₁ and A ₂ to display the alkylene group with a carbon 2-4. )

[Chemical 7] (Wherein, R ₁ represents a methylation group, Ar ₁ and Ar
₂ represents an aryl group which may be substituted with a halogen atom, an alkyl group, an alkoxy group or a substituted amino group, and k represents an integer of 2 . )

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophotographic photosensitive member of the present invention will be described in more detail below. The drawing is a schematic cross-sectional view of an embodiment of the electrophotographic photosensitive member of the present invention . In FIG. 1, a charge generation layer 1 and a charge transport layer 2 are formed on a conductive support 3. In FIG. 2, a subbing layer 4 is provided on the conductive support 3, and in FIG. 3, a protective layer 5 is provided on the surface, and in FIG. and both of the protective layer 5 is Ru have <br/> provided.

Examples of the conductive support include metals such as aluminum, nickel, chromium and stainless steel, and aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide and IT.
Examples thereof include a plastic film provided with a thin film of O or the like, or paper and a plastic film coated or impregnated with a conductivity-imparting agent. These conductive supports are used in a suitable shape such as a drum shape, a sheet shape, and a plate shape, but are not limited thereto. Further, if necessary, the surface of the conductive support may be subjected to various treatments within a range that does not affect the image quality.
For example, surface anodic oxide coating treatment, thermal hydroxylation treatment or chemical treatment, coloring treatment, or irregular reflection treatment such as graining can be performed.

In the present invention, it is preferable to provide an undercoat layer between the conductive support and the photosensitive layer. This undercoat layer prevents the injection of charges from the conductive support to the photosensitive layer during charging of the photosensitive layer, and acts as an adhesive layer that integrally holds the photosensitive layer to the conductive support. Alternatively, in some cases, it exhibits a function of preventing the reflected light of the conductive support from being reflected. Examples of the material 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, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, water-soluble polyester resin, nitrocellulose, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, polyacrylamide Known materials such as a zirconium chelate compound, a titanyl chelate compound, a titanyl alkoxide compound, an organic titanyl compound, and a silane coupling agent can be used. These materials can be used alone or in combination of two or more. Further, it can be mixed with fine particles such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, barium titanate, and silicone resin. As a coating method for forming the undercoat layer, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method is adopted. It The thickness of the undercoat layer is 0.01 to 10 μm, preferably 0.05 to 2 μm.
m is suitable.

[0014]

The charge generation layer can be formed by vacuum-depositing the charge generation material or by dispersing and coating the charge generation material in a binder resin in an organic solvent. As the charge generation material used in the present invention, amorphous selenium, crystalline selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys,
Inorganic photoconductive materials such as granular selenium, zinc oxide, and titanium oxide, phthalocyanine-based, squarylium-based, anthanthrone-based, perylene-based, azo-based, anthraquinone-based, pyrene-based, pyrylium salts, thiapyrylium salts and other organic pigments and dyes Is used.

Among these, the photoconductors using phthalocyanine pigments, especially metal-free phthalocyanine, titanyl phthalocyanine, and gallium phthalocyanine have high sensitivity at the near infrared semiconductor laser wavelength (780 to 830 nm) and stable electrical characteristics for a long period of time. Show. Specifically, at the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα, at least 6.8 °, 1
X by gallium phthalocyanine, CuKα, having strong diffraction peaks at 2.8 °, 15.8 ° and 26.0 °
At the Bragg angle (2θ ± 0.2 °) of the line diffraction spectrum, at least 7.5 °, 9.9 °, 12.5 °,
16.3 °, 18.6 °, 25.1 ° and 28.3 °
Hydroxygallium phthalocyanine (see FIG. 5 ) having a strong diffraction peak at, and at least Bragg angles (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα of at least 7.4 °, 16.6 °, 25.5 ° and 28.3
Chlorogallium phthalocyanine having a strong diffraction peak at 90 ° can be mentioned as a preferable example. Also,
In the visible light wavelength region, anthanthrone-based pigments show stable electrical characteristics over a long period of time, and granular selenium, particularly granular trigonal selenium, shows stable electrical characteristics over a long period of time, as well as higher sensitivity characteristics. .

As the binder resin in the charge generation layer, polyvinyl butyral resin, polyvinyl formal resin,
Partial acetalized polyvinyl acetal resin, such as partially acetalized polyvinyl acetal resin in which a part of butyral is modified with formal or acetoacetal, polyamide resin,
Polyester resin, modified ether type polyester resin,
Polycarbonate resin, acrylic resin, polyvinyl chloride resin, 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,
Examples thereof include polyurethane resin, poly-N-vinylcarbazole resin, polyvinylanthracene resin, polyvinylpyrene and the like.

Of these, polyvinyl acetal resins, vinyl chloride-vinyl acetate copolymers, phenoxy resins and modified ether type polyester resins are particularly preferable. These resins can well disperse the phthalocyanine-based or anthanthrone-based pigment and granular trigonal selenium, and can obtain a dispersion coating liquid that is stable for a long period of time without pigment aggregation. Therefore, the coating liquid is used. As a result, a uniform film is formed, and as a result, electrical characteristics can be improved and image quality defects can be reduced. However, the resin is not limited to these as long as the resin can form a film in a normal state. These binder resins may be used alone or in combination of two or more. The mixing ratio of the charge generating material and the binder resin is 5: 1 by volume.
A range of 1: 2 is preferred.

Solvents used in preparing the coating liquid include methanol, ethanol, n-propanol, and n.
-Butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, chlorobenzene, methyl acetate,
Commonly used organic solvents such as n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride and chloroform may be used alone or in combination of two or more. As a coating method of the coating liquid, a commonly used method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method or the like can be used. . The thickness of the charge generation layer is generally set in the range of 0.01 to 5 μm, preferably 0.1 to 2.0 μm. If the thickness is less than 0.01 μm, it becomes difficult to uniformly form the charge generation layer, and if it exceeds 5 μm, the electrophotographic characteristics tend to be remarkably deteriorated.

The charge transport layer contains at least one triarylamine compound represented by the above general formula (III) as a charge transport material.

Further, other charge transport materials, for example, quinone compounds such as p-benzoquinone, chloranil, bromoanil, anthraquinone, fluorenone compounds such as tetracyanoquinodimethane compound 2,4,7-trinitrofluorenone, xanthone. Compounds, benzophenone compounds, cyanovinyl compounds, electron withdrawing substances such as ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, An electron donating substance such as a hydrazone compound or a polymer having a group composed of these compounds in the main chain or side chain may be used in combination.

Specific examples of the triarylamine compound used in the present invention include those shown in Tables 1 to 3 below. These may be used alone or in admixture of two or more. You may use. However, it is not limited to these.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[0027]

[0028]

[0029]

The binder resin in the charge transport layer has a viscosity average molecular weight of 10,000 to 2 in which the repeating structural unit is composed of the repeating structural unit represented by the general formula (I) or (II).
00000 polyarylate resin Ru is used.

[0031] In the present invention, the general formula (I) or (II) polyarylate resins consisting repeating structural unit represented by, if relatively uniform polyarylate resin molecular weight distribution, viscosity average molecular weight Those in the range of 20,000 to 100,000 are preferable. When the viscosity average molecular weight is less than 10,000, the viscosity of the coating solution is low, the required film thickness cannot be obtained, and the film thickness becomes uneven when dip coating. Even in the case of 10,000 to 20,000, the formed coating film has low mechanical strength and poor wear resistance. Two
On the other hand, if it is more than 0,000, there is a problem that the viscosity of the coating solution is too high and it becomes difficult to control the required film thickness. However, these problems are caused by the viscosity average molecular weight of 10,000 to 2
Since it is improved by appropriately mixing and using the above polyarylate resin of 0,000, the above polyarylate resins having different viscosity average molecular weights may be mixed and used.
Further, a mixture of different polyarylate resins or polycarbonate resins or a copolymerized one may be used as long as the functions and effects of the polyarylate resin are not impaired.

The above-mentioned polyarylate resin in the present invention is produced by a usual method of solution polymerization using a bisphenol compound represented by the following general formula (I ') or (II') and terephthalic acid dichloride. You can

[Chemical 9] (Wherein, X and X 'are hydrogen atoms frame other represents a methyl group, Y and Y' Represents a methyl group or a phenyl group,
A ₁ and A ₂ represent an alkylene group having 2 to 4 carbon atoms.
You )

Among the above polyarylate resins in the present invention, the repeating structural units have the following structural formulas (I-1) to (I-1).
Those selected from (I-3) and (II-1) to (II-2) are preferably used.

[Chemical 10] (In the formula, A ₁ and A ₂ represent an alkylene group having 2 to 4 carbon atoms.)

[0034]

[Chemical 12] (In the formula, A ₁ and A ₂ represent an alkylene group having 2 to 4 carbon atoms.)

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

Further, as a solvent used when the charge transport layer is provided, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated aromatic hydrocarbons such as chlorobenzene, ketones such as acetone and methyl ethyl ketone,
Examples of commonly used organic solvents include halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents can be used alone or in combination of two or more. Further, as a coating method, a usual method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method and a curtain coating method can be used. The thickness of the charge transport layer used in the present invention is generally 5 to 70 μm, preferably 10 to 50 μm.
It is set to the range of. When this film thickness is less than 5 μm,
The initial charging potential tends to be low, and if it exceeds 70 μm, electrophotographic characteristics and image quality tend to be deteriorated.

Further, for the purpose of preventing deterioration of the electrophotographic photosensitive member due to ozone or oxidizing gas generated in the copying machine, or light or heat, an antioxidant, a light stabilizer, a heat stabilizer, etc. are contained in the photosensitive layer. Additives can be added. Examples of antioxidants include hindered phenols, hindered amines, paraphenylenediamines, aryl alkanes, hydroquinones, spirochromans, spiroindanones and their derivatives, organic sulfur compounds and organic phosphorus compounds. Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.

[0038] Te electrophotographic photoreceptor odor of the present invention, on the conductive charge transport layer may be formed coercive Mamoruso.

[0039]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, "part" in an Example and a comparative example means a weight part.

Example 1 A zirconium compound (trade name:
Organix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) 10 parts and a silane compound (trade name: A1110, manufactured by Nippon Unicar Co., Ltd.) 1 part, and a solution consisting of 40 parts of i-propanol and 20 parts of butanol are applied by a dip coating method,
It was heated and dried at 150 ° C. for 10 minutes to form an undercoat layer having a film thickness of 0.1 μm. Next, as a charge generating material, 1 part of hydroxygallium phthalocyanine having an X-ray diffraction spectrum shown in FIG. 5 , 1 part of a carboxyl-modified vinyl chloride-vinyl acetate copolymer (trade name: VMCH, manufactured by Union Carbide Co.) and 100 parts of chlorobenzene. The mixture obtained in (1) was dispersed together with glass beads in a sand mill for 1 hour, and the obtained coating solution was applied onto the above-mentioned undercoat layer by a dip coating method, followed by heat drying at 100 ° C. for 10 minutes to obtain a film having a thickness of 0.25 μm. A charge generation layer was formed.

Next, 12 parts of a polyarylate resin (viscosity average molecular weight 42,500) consisting of the repeating structural unit represented by the following general formula (A-1) and a triarylamine compound (the above-mentioned compound III- 1
4 ) 8 parts, and further dissolved in 100 parts of monochlorobenzene, the obtained coating solution is applied on the above charge generation layer, and dried by heating at 115 ° C. for 60 minutes to a film thickness of about 20 μm.
m charge transport layer was formed.

[Chemical 14]

As described above, the photosensitive layer having a laminated structure was formed on the drum-shaped aluminum substrate. The electrophotographic photoreceptor thus obtained was mounted on a modified laser beam printer (XP-15, manufactured by Fuji Xerox Co., Ltd.),
Without paper feeding, that is, without transferring to paper, a print running test up to 100,000 sheets is performed under the environment of 20 ° C and 45% RH, the abrasion amount before and after copying is measured, and the image quality is evaluated. did. The results are shown in Table 7 below.

COMPARATIVE EXAMPLE 1 Instead of the polyarylate resin having the repeating structural unit represented by the formula (A-1) in the charge transport layer in Example 1, a poly having the repeating structural unit represented by the following general formula (C) was used. Arylate resin (viscosity average molecular weight 43,70
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 0) was used, and the same test was conducted. The results are shown in Table 7.

[Chemical 15]

Example 2 Instead of the polyarylate resin comprising the repeating structural unit represented by the formula (A-1) of the charge transport layer in Example 1, a repeating structural unit represented by the following general formula (A-2) was used. Polyarylate resin (viscosity average molecular weight 39,5
The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that (00) was used, and the same test was conducted. The results are shown in Table 7.
Shown in.

[Chemical 16]

Comparative Example 2 Instead of the polyarylate resin having the repeating structural unit represented by the formula (A-2) in the charge transport layer in Example 2, the polyarylate having the repeating structural unit represented by the following general formula (D) was used. Arylate resin (viscosity average molecular weight 38,20
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 0) was used, but the polyarylate resin was not dissolved in chlorobenzene, and the photosensitive member could not be prepared.

[Chemical 17]

Example 3 Instead of the polyarylate resin comprising the repeating structural unit represented by the formula (A-1) in the charge transport layer in Example 1, a repeating structural unit represented by the following general formula (A-3) was used. Polyarylate resin (viscosity average molecular weight 51,9
The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that (00) was used, and the same test was conducted. The results are shown in Table 7.
Shown in.

[Chemical 18]

Comparative Example 3 Instead of the polyarylate resin having the repeating structural unit represented by the formula (A-3) in the charge transporting layer in Example 3, a poly having the repeating structural unit represented by the following general formula (E) was used. Arylate resin (viscosity average molecular weight 52,80
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 0) was used, and the same test was conducted. The results are shown in Table 7.

[Chemical 19]

Example 4 Instead of the polyarylate resin comprising the repeating structural unit represented by the formula (A-1) in the charge transport layer in Example 1, a repeating structural unit represented by the following general formula (A-4) was used. Polyarylate resin (viscosity average molecular weight 43,9
The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that (00) was used, and the same test was conducted. The results are shown in Table 7.
Shown in.

[Chemical 20]

Comparative Example 4 Instead of the polyarylate resin having the repeating structural unit represented by the formula (A-4) in the charge transport layer in Example 4, a poly having the repeating structural unit represented by the following general formula (F) was used. Arylate resin (viscosity average molecular weight 41, 70
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 0) was used, but the polyarylate resin was not dissolved in chlorobenzene, and the photosensitive member could not be prepared.

[Chemical 21]

Example 5 Instead of the polyarylate resin comprising the repeating structural unit represented by the formula (A-1) in the charge transport layer in Example 1, a repeating structural unit represented by the following general formula (A-5) was used. Polyarylate resin (viscosity average molecular weight 55,3
The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that (00) was used, and the same test was conducted. The results are shown in Table 7.
Shown in.

[Chemical formula 22]

Comparative Example 5 Instead of the polyarylate resin having the repeating structural unit represented by the formula (A-5) in the charge transport layer in Example 5, a poly-containing resin having the repeating structural unit represented by the following general formula (G) was used. Arylate resin (viscosity average molecular weight 54,20
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 0) was used, and the same test was conducted. The results are shown in Table 7.

[Chemical formula 23]

Comparative Example 6 The charge transport material of the charge transport layer in Example 1 (III- 1
4 ) instead of using a butadiene derivative represented by the following structural formula (CTM-1) as a charge transport material,
An electrophotographic photosensitive member was produced in the same manner as in Example 1, and the same test was performed. The results are shown in Table 7.

[Chemical formula 24]

Comparative Example 7 The following structural formula (CTM-2) was used instead of the charge transporting material (Exemplified Compound III- 14 ) of the charge transporting layer in Example 2.
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the hydrazone derivative represented by (4) was used as the charge transport material, and the same test was conducted. The results are shown in Table 7.

[Chemical 25]

Comparative Example 8 The following structural formula (CTM-3) was used instead of the charge transporting material (Exemplified Compound III- 14 ) of the charge transporting layer in Example 4.
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the hydrazone derivative represented by (4) was used as the charge transport material, and the same test was conducted. The results are shown in Table 7.

[Chemical formula 26]

Examples 6 to 8 Instead of the polyarylate resin comprising the repeating structural unit represented by the structural formula (A-1) having a viscosity average molecular weight of 42,500 in Example 1, 20,
A photoconductor was prepared in the same manner as in Example 1 except that those of 200, 32, 300, 54, 100 were used.
The same test was performed. The results are shown in Table 7.

Examples 9 to 11 Instead of the polyarylate resin having the repeating structural unit represented by the structural formula (A-2) in Example 2 having a viscosity average molecular weight of 39,500, 20,
Example 2 A photoconductor was prepared in the same manner as in Example 2 except that those of 100, 30, 700, 55, 700 were used.
The same test was performed. The results are shown in Table 7.

[0057]

[Table 7]

As is clear from Table 7, Examples 6 to 11
In the case of the electrophotographic photosensitive member of No. 3, stable image quality was obtained for a long period of time, and there was no problem. Further, in the case of the polyarylate resin having a viscosity average molecular weight of 20,100, the image quality defect was observed in a part as the abrasion amount increased, but the problem was small. It was found that when the viscosity average molecular weight is less than 20,000, the amount of wear is further increased and the problem of image quality maintenance is further increased. Therefore, the polyarylate resin used as the binder resin is
Those having a viscosity average molecular weight of 20,000 or more are preferable.

[0059]

In the electrophotographic photoreceptor of the present invention,
As the binder resin for the photosensitive layer, the above-mentioned general formula (I) or (I
A polyarylate resin having a repeating structural unit represented by the formula (I) is used, and the charge transporting material is represented by the general formula (III).
By using the triarylamine-based material or benzidine-based compound shown in, the abrasion resistance, corona discharge resistance, and toner filming resistance are high, and the photosensitive layer can be used repeatedly in a copying machine or printer for a long time. It has high durability that does not cause problems, does not deteriorate the electrophotographic characteristics, and can obtain a copy image with excellent image quality for a long period of time. Further, as is apparent from the above comparison, the electrophotographic photosensitive member of the present invention maintains excellent repetitive stability and has high printing durability.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of an electrophotographic photosensitive member of the present invention.

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

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

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

FIG. 5: Hydroxygallium phthalo used in Examples
It is a powder X-ray-diffraction spectrum figure of cyanine.

[Explanation of symbols]

1 ... Charge generating layer, 2 ... Charge transporting layer, 3 ... Conductive support,
4 ... Undercoat layer, 5 ... Protective layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-40165 (JP, A) JP-A-62-267748 (JP, A) JP-A-61-53647 (JP, A) JP-A-9- 34139 (JP, A) JP 7-120942 (JP, A) JP 5-72751 (JP, A) JP 3-63653 (JP, A) JP 3-33860 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 5/00 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. An electrophotographic photoreceptor having a photosensitive layer provided on a conductive support, wherein the outermost surface of the photosensitive layer is a repeating resin represented by the following general formula (I) or (II) as a binder resin. A charge transport layer containing at least one polyarylate resin having a viscosity average molecular weight of 10,000 to 200,000 as a unit.
Electrophotographic photoreceptor, characterized in that that. [Chemical 1] (Wherein, X and X 'are hydrogen atoms frame other represents a methyl group, Y and Y' Represents a methyl group or a phenyl group,
A ₁ and A ₂ to display the alkylene group with a carbon 2-4. ) 2. The electrophotographic photoreceptor according to claim 1, which contains at least one triarylamine compound represented by the following general formula (III) as a charge transport material for the photosensitive layer. . [Chemical 2] (Wherein, R ₁ represents a methylation group, Ar ₁ and Ar
₂ represents an aryl group which may be substituted with a halogen atom, an alkyl group, an alkoxy group or a substituted amino group, and k represents an integer of 2 . ) 3. The repeating structural unit represented by the general formula (I) is selected from the following structural formulas (I-1) to (I-3). Electrophotographic photoconductor. [Chemical 3] (In the formula, A ₁ and A ₂ represent an alkylene group having 2 to 4 carbon atoms.) 4. The repeating structural unit represented by the general formula (II) is selected from the following structural formulas (II-1) and (II-2). Electrophotographic photoconductor. [Chemical 4] (In the formula, A ₁ and A ₂ represent an alkylene group having 2 to 4 carbon atoms.) 5. The electrophotographic photoreceptor according to claim 1, wherein the polyarylate resin contains a polyarylate resin having a viscosity average molecular weight of 20,000 or more.