JPH07175240A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To provide an electrophotographic photoreceptor high in sensitivity, small in the wear of a photosensitive layer of the electrophotographic photoreceptor, the degradation of image quality and the deterioration of sensitivity and excellent in image stability. CONSTITUTION:In the electrophotographic photoreceptor produced by laminating a charge generation layer and a charge transport layer on a substrate, the charge generation layer contains a charge generating material expressed by a formula and the charge transfer layer contains polycarbonate resin. In the formula, R1 represents (un)substituted alkyl group or (un)substituted phenyl group, R2 represents hydrogen atom, cyano group, carboamide group, methoxy or ethoxy carbonyl group or methyl or ethyl carbonyl group. Each of R3 and R4 represents hydrogen atom, halogen atom, nitro group, alkoxyl group or (un)substituted alkyl group, D represents -Ar-Ar- or -Ar-Y-Ar- and Ar represents (un)substituted phenylene group and Y represents bivalent linkage group.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photoreceptor having high sensitivity, less wear of the photosensitive layer of the electrophotographic photoreceptor, less deterioration of image quality, less deterioration of sensitivity, and excellent image stability.

[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, as an electrophotographic photoreceptor, an inorganic photoreceptor having an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a photosensitive layer main component has been widely used. Recently, as a photosensitive layer of an electrophotographic photoreceptor, a carrier generation function and a carrier transport function are shared by different substances,
There is a trend to put into practical use an organic photoconductor having high sensitivity and high durability by selecting a substance that exhibits each function from a wide range according to desired characteristics.

Such a function-separated type organic photoreceptor is conventionally mainly used for negative charging, and a thin carrier generating layer is provided on a support, as described in JP-A-60-247647. 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 high polymer crystallinity, so that its solution is apt to gel and its application becomes impossible in about 1 to 2 days. have. Also,
When a film is formed by coating, crystalline polycarbonate is likely to be deposited on the surface of the film during the formation of a coating film to form a convex portion, which causes tailing of the coating film to reduce the yield, or Toner adheres to the convex portion during use and remains without being cleaned, and image defects due to so-called poor cleaning are likely to occur.

An electrophotographic photoreceptor using the above 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 the smooth 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 surface is applied. 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 surface properties and slipperiness, and are effective for dispersing suspension materials and improving dispersion stability in 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 (JP-A-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) has been proposed, but it does not have sufficient surface strength and surface smoothness, is vulnerable to abrasion and scratches, causes deterioration of image quality during repeated use, and has a problem of sensitivity deterioration due to film thickness reduction due to abrasion. Have a point.

[0011]

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.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor having a charge generation layer and a charge transport layer laminated on a substrate, wherein the charge generation layer has a charge represented by the following general formula (1). A charge generating layer containing a generating substance, and containing, as a binder resin, a copolymer compound having a repeating unit represented by the following general formula (B ₁ ) and general formula (B ₂ ) as a main component. Is achieved by the electrophotographic photoreceptor.

[0013]

[Chemical 3]

In the formula, R ₁ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group, and R ₂
Represents a hydrogen atom, a cyano group, a carboxamide group, a methoxy or ethoxycarbonyl group, or a methyl or ethylcarbonyl group. R ₃ and R ₄ represent a hydrogen atom, a halogen atom, a nitro group, an alkoxy group or a substituted or unsubstituted alkyl group, and D is —Ar—Ar— group or —Ar—.
It represents a Y-Ar- group, where Ar represents a substituted or unsubstituted phenylene group and Y represents a divalent linking group.

[0015]

[Chemical 4]

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

In the present invention, by containing the charge generating substance represented by the general formula (1) in the charge generating layer, excellent electrophotographic characteristics such as charge retention, sensitivity and residual potential can be obtained. By containing a polycarbonate resin composed of the copolymer compound of ₁ ) and (B ₂ ) in the charge transport layer, an electrophotographic photosensitive member that exhibits stable characteristics with little thickness loss even when repeatedly used is obtained. There was a remarkable effect of being able to be.

The compound represented by the general formula (1) of the present invention will be described in more detail.

Examples of the substituted or unsubstituted alkyl group represented by R ₁ include methyl group, ethyl group, propyl group, i-propyl group, t-butyl group, pentyl group and hexyl group. The alkyl group includes those having a substituent, and examples of the substituent include a halogen atom (for example, each atom of chlorine, bromine, iodine, fluorine, etc.), a carboxyl group, a sulfo group, a nitro group, a hydroxyl group, and a mercapto. Group, amino group (for example, amino group, diethylamino group, etc.), alkoxy group (for example, methoxy group, ethoxy group,
n-butoxy group, n-octyloxy group, isopropoxy group, etc.), aryloxy group (phenyloxy group, naphthyloxy group, etc.), carbamoyl group (eg aminocarbonyl group, methylcarbamoyl group, n-pentylcarbamoyl group, phenyl) Carbamoyl group, etc.), amide group (eg, methylamido group, benzamido group, n-octylamido group, etc.), cyano group and the like.

Examples of the aryl group represented by R ₁ include a phenyl group and a naphthyl group. The aryl group includes those having a substituent, and examples of the substituent include the groups described above as the substituent of the alkyl group.

Preferred substituents represented by R ₁ are:
Lower alkyl groups are mentioned.

R ₂ represents a hydrogen atom, a cyano group, a carboxamide group, a methoxy or ethoxycarbonyl group or a methyl or ethylcarbonyl group, and a cyano group or a carboxamide group is preferable.

R ₃ and R ₄ are a hydrogen atom, a halogen atom,
It represents a nitro group, an alkoxy group or a substituted or unsubstituted alkyl group, and examples of the substituent of the alkyl group include the substituents of the alkyl group described above.

D is an --Ar--Ar-- group or --Ar--YA
Although it represents an r-group, Ar represents a substituted or unsubstituted phenylene group, and examples of the substituent include the substituents of the alkyl group described above. Preferred as D is a phenylene group substituted with a halogen atom, an alkoxy group or an unsubstituted alkyl group.

Y represents a divalent linking group, and examples of the linking group include methylene group, ethylene group, oxy group, carbonyl group, carbonylamino group, ureido group, thio group, dithio group, sulfinyl group, sulfonyl group, An imino group etc. are mentioned. Preferred is a methylene group or an ethylene group.

Examples of the compound represented by the general formula (1) used in the present invention are shown below.

[0027]

[Table 1]

The bisazo compound represented by the general formula (1) of the present invention can be easily synthesized, for example, by the method described in JP-A-63-155052.

Next, the general formulas (B ₁ ) and (B ₂ ) according to the present invention are described.
And typical examples of the copolymer compound represented by the general formulas (B ₁ ) and (B ₂ ) are shown below, but the compound examples according to the present invention are not limited thereto.

[0030]

[Chemical 5]

[0031]

[Chemical 6]

[0032]

[Chemical 7]

[0033]

[Chemical 8]

[0034]

[Chemical 9]

[0035]

[Chemical 10]

[0036]

[Table 2]

X, y in the copolymer compound in Table 2 above
The ratio (copolymerization ratio) of x: y is in the range of 95: 5 to 5:95, and more preferably in the range of 95: 5 to 50:50.

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

The polycarbonate resin composed of the copolymer compound of the general formulas (B ₁ ) and (B ₂ ) of the present invention is used in the presence of an inert solvent such as methylene chloride or 1,2-dichloroethane.
To a mixture of phenolic compounds of various repeating units,
Add an alkaline aqueous solution or pyridine as an acid acceptor,
It is synthesized by a method of cocondensing while introducing phosgene.

The charge generating substance represented by the general formula (1) of the present invention is dissolved in a suitable organic solvent, dispersed in a binder, and coated on a substrate to form a charge generating layer. Suitable organic solvents include, for example, hexane, benzene, toluene, hydrocarbons such as xylene, methylene chloride, methylene bromide, 1,2-dichloroethane, syn-tetrachloroethane, cis-1,2-dichloroethylene, Halogenated hydrocarbons such as 1,1,2-trichloroethane, 1,1,1-trichloroethane, 1,2-dichloropropane, chloroform, bromoform, chlorobenzene, ketones such as acetone, methyl ethyl ketone, cyclohexanone, acetic acid Ethyl, esters such as butyl acetate, methanol, ethanol, propanol, butanol, cyclohexanol, heptanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, alcohol such as cellosolve acetate and derivatives thereof, tetrahydrofuran, 1,4-dioxane, furan,
Ethers such as furfural, acetals, amines such as pyridine and butylamine, diethylamine, ethylenediamine, isopropanolamine, nitrogen compounds such as amides such as N, N-dimethylformamide, fatty acids and phenols, carbon disulfide and triethyl phosphate. And sulfur compounds such as phosphorus compounds.

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 resin comprising the copolymer compound of the general formulas (B ₁ ) and (B ₂ ) of the present invention is used as a binder for the charge transport layer.

Generally, the charge transport layer contains a carrier transport substance, but 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 derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc. Is mentioned.

In the present invention, as the binder of the charge transport layer, the above-mentioned binder used in the charge generation layer is used in addition to the polycarbonate resin comprising the copolymer compound of the general formulas (B ₁ ) and (B ₂ ) of the present invention. Can be used together.
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, if necessary, and may also 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.

As the electroconductive 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.

[0050]

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

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

Next, 5 g of polyvinyl butyral resin S-REC BX-1 (Sekisui Chemical Co., Ltd.) was dissolved in 1000 ml of MEK,
Furthermore, 10 g of Exemplified Compound (1-1) was mixed, and then dispersed using a sand mill for 20 hours. 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, 200 g of the compound T and 200 g of the polycarbonate resin (B-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 photoconductor 1 in which an intermediate layer, a charge generation layer and a charge transport layer were sequentially laminated.

[0055]

[Chemical 11]

<Photoreceptor 2> Polycarbonate resin (B-
Photosensitive member 2 was prepared in the same manner as photosensitive member 1 except that bisphenol Z type polycarbonate was used instead of 1).

<Photoreceptor 3> Polycarbonate resin (B-
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> In the same manner as in Photoreceptor 1 except that Exemplified Compound (1-1) was changed to Compound G-1, Photoreceptor 4 was obtained.
It was created.

<Photoreceptor 5> In the same manner as in Photoreceptor 1 except that Exemplified Compound (1-1) was changed to Compound G-2, Photoreceptor 5 was obtained.
It was created.

[0060]

[Chemical 12]

(2) Evaluation Photoreceptors 1 to 5 were mounted on U-Bix 4155 manufactured by Konica Corporation,
As shown in Table 3, a live-action test of 100,000 copies was 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.

[0062]

[Table 3]

From Table 3, the electrophotographic photoreceptor of the present invention is excellent in electrophotographic characteristics such as sensitivity and residual potential, and shows stable characteristics with little film thickness wear even when repeatedly used. You can see that

[0064]

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 generation layer contains a charge generation substance represented by the following general formula (1). In addition, the electrophotographic photosensitive member is characterized by containing as a binder resin a copolymer compound having a repeating unit represented by the following general formulas (B ₁ ) and (B ₂ ) as a main component. [Chemical 1] In the formula, R ₁ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group, and R ₂ represents a hydrogen atom, a cyano group, a carboxamide group, a methoxy or ethoxycarbonyl group, or a methyl or ethylcarbonyl group. . R ₃ and R ₄ represent a hydrogen atom, a halogen atom, a nitro group, an alkoxy group or a substituted or unsubstituted alkyl group, and D is —Ar—Ar— group or —Ar—Y—Ar—.
In the formula, Ar represents a substituted or unsubstituted phenylene group and Y represents a divalent linking group. [Chemical 2] In the formula, R ₁₁ and R ₁₂ are a hydrogen atom, a substituent having 1 to 6 carbon atoms,
It represents an unsubstituted alkyl group, a substituted or unsubstituted aryl group or a cyclic hydrocarbon residue having 4 to 10 carbon atoms, which is formed by including R ₁₁ and R ₁₂ . R ₁₃ , R ₁₄ , R ₁₅ and R ₁₆ are each 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 an alkyl group having 4 to 10 carbon atoms. Cyclic hydrocarbon group, l, m, p and q are 1
Is a positive integer of ˜4.