JPH07199488A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To enhance the electrophotographic characteristic of an electrophotographic photoreceptor and to reduce the abrasion loses of film thickness by containing a specific polycarbonate resin in a charge transporting layer. CONSTITUTION:A charge generating layer and a charge transporting layer are laminated on a substrate. The charge transporting layer contains a copolymer compound composed chiefly of repeating units represented by formula I; and a polymer represented by formula II. In formula I, R11, R12 represent hydrogen atom, a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group, etc.; R13 <->-R16 are hydrogen atom, halogen atom, a substituted or unsubstituted alkyl group of l to 6 carbon atoms, an unsubstituted alkyl group, or a substituted or unsubstituted aryl group, etc.; and (l), (m), (p), (q) are integers from l to 4. In formula II, R21, R22 are hydrogen atom, halogen atom, a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, or a cyclic hydrocarbon residue of 4 to 10 carbon atoms; (r), (s) are positive integers from 1 to 4; and (t) is a positive integer of 1 to 5.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, it relates to an organic electrophotographic photoreceptor.

[0002]

2. Description of the Related Art In an electrophotographic copying machine of the Carlson method, after uniformly charging the surface of a photoconductor, the charge is erased imagewise by exposure to form an electrostatic latent image. With toner, then transfer the toner to paper,
Fix it.

On the other hand, the photoconductor has been subjected to removal of adhering toner, static elimination, and surface cleaning, and is repeatedly used for a long period of time. Therefore, as an electrophotographic photosensitive member, of course, the electrophotographic characteristics such as good charging characteristics and sensitivity and further small dark decay, as well as physical properties such as printing durability, abrasion resistance and moisture resistance upon repeated use. Also, it is required to have good resistance (environmental resistance) to ozone generated during corona discharge and ultraviolet rays during exposure.

Conventionally, selenium has been used as an electrophotographic photoreceptor.
Inorganic photoconductors having an inorganic photoconductive substance such as zinc oxide and cadmium sulfide as a main component of a photosensitive layer have been widely used. In recent years, as a photosensitive layer of an electrophotographic photoreceptor, a carrier generating function and a carrier transporting function are shared by different substances, and substances exhibiting each function are selected from a wide range according to desired characteristics, and high sensitivity and high durability are achieved. There is a trend to put organic photoconductors into practical use.

Such a function-separated type organic photoreceptor is conventionally used mainly for negative charging. As described in JP-A-60-247647, a thin carrier generating layer is provided on a support, and a thin carrier generating layer is provided thereon. The structure is such that a relatively thick carrier transport layer is provided.

As a binder used for such a photoreceptor, it is well known that bisphenol A type polycarbonate exhibits good characteristics in terms of charging characteristics, sensitivity, residual potential and repetitive characteristics. .

However, as a result of investigations by the present inventors,
The bisphenol A type polycarbonate has a drawback that the solution thereof is apt to gel due to the high crystallinity of the polymer and cannot be applied in about 1 to 2 days. Further, when a film is formed by coating, crystalline polycarbonate is likely to be deposited on the surface of the film at the time of forming the coating film to form a convex portion, which causes tailing of the coating film to lower the yield, or The toner adheres to the convex portions during use as a cleaning agent and remains without being cleaned, so that image defects due to so-called poor cleaning are likely to occur.

An electrophotographic photosensitive member using the bisphenol A type polycarbonate as a binder resin is
When it is used as a photoconductor of an electrophotographic copying machine, it has a drawback that it is scratched by a magnetic brush or a cleaning blade to scratch the surface of the photosensitive layer, or the photosensitive layer is gradually worn away.

On the other hand, since the high image quality and good copying workability depend on the smooth and uniform surface property of the photosensitive member having a uniform thickness, the coating composition or coating for forming the constituent layer of the photosensitive member coating constituent layer surface, Film surface defects such as citron skin, pinholes, coating streaks, and cracks (solvent cracks) caused by drying are serious problems in terms of copy characteristics and production technology.

Surfactants are useful for improving the surface property or slipperiness, and are effective for dispersion of suspended solids and improvement of dispersion stability in the case of suspension type paints, and are also dissolved in solution type paints. It has value in promotion and production technology such as improvement of coating property. However, if the type is wrongly selected, interlayer adhesion failure, failure due to its deterioration, or trouble relating to moisture resistance is often caused.

In order to solve the above problems, the introduction of a substituent having a fluorine atom at the carbon between the phenylene rings (Japanese Patent Laid-Open No. 63-6).
5444), substitution of an alkyl group or a halogen atom on a phenylene ring (JP-A-62-148263), or a copolymer of monomers in which both phenylene rings are substituted with a phenyl group or a cyclohexyl group (JP-A-1). 269942, 1-269943) or the use of distyryl in combination with bisphenol Z type polycarbonate as a carrier transporting substance (Japanese Patent Laid-Open No. 64-322).
No. 65) etc. have been proposed.

However, there are still problems such as insufficient surface strength and surface smoothness, weakness against abrasion and scratches, deterioration of image quality during repeated use, and deterioration of sensitivity due to film thickness reduction due to abrasion. .

[0013]

The object of the present invention is to eliminate the above-mentioned drawbacks, high sensitivity, less wear of the photosensitive layer of the electrophotographic photosensitive member, less deterioration of image quality and less deterioration of sensitivity, and image stability. To provide an excellent electrophotographic photoreceptor.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member comprising a substrate on which a charge generation layer and a charge transport layer are laminated, the charge transport layer having the following general formula (1) as a binder resin. This is achieved by an electrophotographic photoreceptor characterized by containing a copolymer compound having a repeating unit represented by the main component and a polymer represented by the general formula (2).

[0015]

[Chemical 3]

In the formula, R ₁₁ and R ₁₂ are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, or a carbon formed by including R ₁₁ and R _12. It represents a cyclic hydrocarbon residue having 4 to 10 atoms. In addition, R ₁₃ , R ₁₄ ,
R ₁₅ and R ₁₆ are hydrogen atom, halogen atom, carbon atom 1
~ 6 substituted, unsubstituted alkyl group, substituted, unsubstituted aryl group or a cyclic hydrocarbon group having 4 to 10 carbon atoms,
l, m, p, and q are positive integers of 1 to 4.

[0017]

[Chemical 4]

In the formula, R ₂₁ and R ₂₂ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group or a cyclic carbon atom having 4 to 10 carbon atoms. Hydrogen residues, r and s are positive integers of 1 to 4, and t is a positive integer of 1 to 5.

In the present invention, by containing the polycarbonate resin represented by the general formulas (1) and (2) in the charge transport layer, it has excellent electrophotographic properties such as charge retention, sensitivity and residual potential, and can be used repeatedly. Even when the above was performed, there was a remarkable effect that an electrophotographic photosensitive member that exhibits stable characteristics with little film thickness loss can be obtained.

The content ratio of the polycarbonate resin of the general formulas (1) and (2) is preferably 95/5 to 5/95, particularly preferably 90/10 to 10/90, and the ratio of (1) is more than this. The larger the value, the lower the scratch resistance of the photoreceptor. Also,
If the ratio of (2) becomes too large, the sensitivity will decrease.

Next, typical specific examples of the polymer components (B ₁ ) and (B ₂ ) constituting the general formula (1) according to the present invention and the copolymer compound composed thereof will be shown. Examples of such compounds are not limited to these.

[0022]

[Chemical 5]

[0023]

[Chemical 6]

[0024]

[Chemical 7]

[0025]

[Chemical 8]

[0026]

[Chemical 9]

[0027]

[Chemical 10]

[0028]

[Table 1]

X in the copolymer compound examples in Table 1 above,
The ratio of y (copolymerization ratio) is in the range of x: y = 95: 5 to 5:95, more preferably 95: 5 to 50:50.

When the ratio of y is 50% or more, the sensitivity and the mechanical strength decrease, so the ratio of y is preferably 50% or less.

The general formula (1) of the present invention is constituted (B ₁ ).
A polycarbonate resin composed of the copolymer compound of (B ₂ ) and (B ₂ ) is a mixture of two types of repeating units of a phenolic compound in the presence of an inert solvent such as methylene chloride or 1,2-dichloroethane, and an alkali as an acid acceptor. It is synthesized by a method in which an aqueous solution or pyridine or the like is added and cocondensation is carried out while introducing phosgene.

Next, specific examples of the compound of the general formula (2) in the present invention are as follows.

[0033]

[Chemical 11]

In the photoconductor of the present invention, the pigments represented by the following representative examples are used as the charge generating substance (CGM).

(1) Azo pigments such as monoazo pigments, bisazo pigments, triazo pigments and metal complex salt azo pigments (2) Perylene pigments such as perylene anhydride, perylene imide (3) Anthraquinone derivatives, anthanthrone derivatives, dibenz Polycyclic quinone pigments such as pyrenequinone derivatives, pyranthrone derivatives, violanthrone derivatives and isobiolanthrone derivatives (4) Indigoid pigments such as indigo derivatives and thioindigo derivatives (5) Phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine The charge generating substance preferably used in the present invention is described in
Polycyclic quinone pigments described in 59-184353, more preferably dibromoanthanthrone pigment, or JP-A 2-20877.
Bisazo pigments, more preferably fluorenone type bisazo pigments represented by the general formula [III], halogen-substituted perylene pigments described in JP-B-3-26384, JP-A-62-54267. Asymmetric perylene pigments described in JP-A Nos. 54-126036, 58-152247, and 59-319.
The perylene pigments described in Nos. 57, 2-251858, 4-62560 and 5-6014, and the bisimidazopyridonoperylene pigments described in Japanese Patent Application No. 3-279764 are preferable.

Further, α-type titanyl phthalocyanine described in JP-A-61-239248, β-type titanyl phthalocyanine described in JP-A-62-67094, C-type titanyl phthalocyanine described in JP-A-63-366, and JP-A-2-309362. I-type titanyl phthalocyanine described in Japanese Patent Application No. 62-173640 is more preferable.

Examples of the binder used in the charge generation layer of the present invention include the following.

(1) Polyester (2) Methacrylic resin (3) Acrylic resin (4) Polyvinyl chloride (5) Polyvinylidene chloride (6) Polystyrene (7) Polyvinyl acetate (8) Styrene copolymer resin (for example, styrene- Butadiene copolymer, styrene-methyl methacrylate copolymer, etc.) (9) Acrylonitrile copolymer resin (for example, vinylidene chloride-acrytronitrile copolymer, etc.) (10) Vinyl chloride-vinyl acetate copolymer Polymer (11) Vinyl chloride-vinyl acetate-maleic anhydride copolymer (12) Silicone resin (13) Silicone-alkyd resin (14) Phenolic resin (for example, phenol-formaldehyde resin, cresol-formaldehyde resin, etc.) (15) Styrene-alkyd resin (16) Poly-N-vinylcarbazole (17) Polyvinyl butyral (18) Polyvinyl formal (19) Rehydroxystyrene These binders can be used alone or as a mixture of two or more kinds.

The polycarbonate resins of the general formulas (1) and (2) of the present invention are used as a binder for the charge transport layer.

Generally, the charge transport layer contains a carrier transport substance, and the carrier transport substance is not particularly limited. For example, oxazole derivative, oxadiazole derivative, thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, pyrazoline derivative, amine derivative, oxazolone derivative, benzothiazole Examples thereof include derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene.

In the present invention, in addition to the polycarbonate resin of the general formulas (1) and (2) of the present invention, the binder used in the charge generation layer described above can be used as a binder of the charge transport layer. The charge transport layer is dissolved in the above-mentioned organic solvent and applied on the charge generation layer.

In addition, the photoreceptor of the present invention may further contain an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, and may further contain a dye for correcting color sensitivity.

Further, in the present invention, an intermediate layer may be provided between the substrate and the charge generation layer, if necessary. The intermediate layer functions as an adhesive layer or a blocking layer, and in addition to the binder resin, for example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride. Copolymers, casein, alcohol-soluble nylon, starch and the like are used.

In the present invention, the photosensitive layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential to reducing fatigue during repeated use.

Examples of the electron-accepting substance which can be used here include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride and 3-nitrophthalic anhydride. Acid, 4-nitrophthalic anhydride, pyromellitic dianhydride,
Mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, bulmannyl, Dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7-dinitrofluorenone, 2,4,7-trinitrofluorenone,
2,4,5,7-Tetranitrofluorenone, 9-fluorenylidene (dicyanomethylene malonodinitrile), polynitro-9
-Fluorenylidene- (dicyanomethylene malonodinitrile), picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid,
Examples include 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds having a high electron affinity. The addition ratio of the electron-accepting substance is 100: 0.01 to 200, preferably 100: 0.1 to 100, by weight, organic pigment used in the present invention: electron-accepting substance.

Further, organic amines can be added to the photosensitive layer of the present invention for the purpose of improving the charge generation function of CGM, and it is particularly preferable to add a secondary amine. These compounds are described in JP-A-59-218447 and JP-A-62-8160.

As the conductive substrate used in the construction of the electrophotographic photosensitive member of the present invention, the following are mainly used, but not limited thereto.

1) Metal plate such as aluminum plate and stainless plate 2) On a support such as paper or plastic film,
A thin metal layer such as aluminum, palladium, or gold provided by lamination or vapor deposition 3) On a support such as paper or plastic film,
Examples thereof include those in which a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is provided by coating or vapor deposition.

[0049]

EXAMPLES Examples of the present invention will be specifically described below.

(1) Preparation of Photoreceptor <Photoreceptor 1> Polyamide resin CM-8000 (Toray Industries, Inc.) 30 g was added to methanol 900
It was put into a mixed solvent of 100 ml and 1-butanol 100 ml, and dissolved by heating at 50 ° C. After cooling to room temperature, use this solution to
An intermediate layer having a thickness of 0.5 μm was formed by dip coating on an aluminum drum having a length of 80 mm and a length of 355.5 mm.

Next, 5 g of polyvinyl butyral resin S-REC BX-1 (Sekisui Chemical Co., Ltd.) was added to methyl ethyl ketone (ME
K) Dissolved in 1000 ml, further mixed with 10 g of Exemplified Compound G shown in the following "Chemical Formula 12", and dispersed for 20 hours using a sand mill. Using this solution, a charge generation layer having a thickness of 0.5 μm was formed on the above intermediate layer by dip coating.

Then, 100 g of Exemplified Compound T and 50 g of polycarbonate resin (B-1) and 50 g of (C-1) were dissolved in 1000 ml of dichloromethane to prepare a coating solution for the charge transport layer. Using this solution, a charge transport layer having a thickness of 20 μm was formed on the charge generation layer by dip coating.

Finally, it was heated and dried at 100 ° C. for 1 hour to prepare a photoreceptor 1 in which an intermediate layer, a charge generation layer and a charge transport layer were sequentially laminated.

<Photoreceptor 2> Exemplified Compounds (B-1), (C
Photoconductor 1 except that the combination of (-1) was changed to (C-1) alone
Photoreceptor 2 was prepared in the same manner as in.

<Photoreceptor 3> Polycarbonate resin (C-
A photoconductor 3 was prepared in the same manner as the photoconductor 1 except that 1) was changed to bisphenol A type polycarbonate.

<Photoreceptor 4> Exemplified Compounds (B-1), (C
Photoconductor 1 except that the combination of (-1) was changed to (B-1) alone
Photoreceptor 4 was prepared in the same manner as in.

<Photoreceptor 5> A photoreceptor 5 was prepared in the same manner as the photoreceptor 1 except that the exemplified compound (B-1) was changed to bisphenol A type polycarbonate.

[0058]

[Chemical 12]

(2) Evaluation The photoconductors 1 to 5 were attached to U-BIX 4155 manufactured by Konica Corporation,
As shown in Table 2, 100,000 copy live-action tests were conducted. Evaluation,
It was determined based on the presence / absence of image defects during actual shooting, the amount of change in surface potential before and after actual shooting, and the amount of film thickness loss.

In the table, Vb is the surface potential of the photosensitive member after exposure for the portion where the original density is 1.3, and Vw is the surface potential of the photosensitive member after exposure for the portion where the original density is 0.00.

[0061]

[Table 2]

From Table 2, the electrophotographic photoreceptor of the present invention is excellent in electrophotographic characteristics such as sensitivity and residual potential, and exhibits stable characteristics with little film thickness loss even when repeatedly used. You can see that

[0063]

According to the present invention, an electrophotographic photosensitive member having high sensitivity, less wear of the photosensitive layer of the electrophotographic photosensitive member, less deterioration in image quality and sensitivity, and excellent in image stability can be obtained.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a charge generation layer and a charge transport layer laminated on a substrate, wherein the charge transport layer contains a repeating unit represented by the following general formula (1) as a binder resin as a main component. An electrophotographic photosensitive member comprising a copolymer compound and a polymer represented by the general formula (2). [Chemical 1] In the formula, R ₁₁ and R ₁₂ are a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, or a carbon atom number 4 formed by including R ₁₁ and R _12. Represents ~ 10 cyclic hydrocarbon residues. Also, R ₁₃ , R ₁₄ , R ₁₅ and R
₁₆ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group or a cyclic hydrocarbon group having 4 to 10 carbon atoms, and 1, m,
p and q are positive integers of 1 to 4. [Chemical 2] In the formula, R ₂₁ and R ₂₂ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group, or a cyclic hydrocarbon residue having 4 to 10 carbon atoms. , R, s are positive integers of 1 to 4, and t is a positive integer of 1 to 5.