JPH0887124A - Electrophotographic photoreceptor and electrophotographic device equipped with that electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To improve the production efficiency and injection efficiency of a charge carrier and to obtain excellent characteristics of sensitivity and potential stability for repeated use by incorporating an azo pigment having a specified structure in a photosensitive layer. CONSTITUTION: This electrophotographic photoreceptor has a photosensitive layer on a conductive supporting body. The photosensitive layer contains an azo pigment having org. residue expressed by formula. In formula, R1 and R2 be the same blame or different and are hydrogen atoms, alkyl groups which may have substituents, aralkyl groups which may have substituents, aryl groups which may have substituents, heterocyclic groups which may have substituents, or cyclic amino groups including the nitrogen atom bonded with R1 , R2 in the ring, and Z is an oxygen atom or sulfur atom. Considering the interaction between pigment molecules due to hydrogen bond force, it is preferable that R1 is a hydrogen atom, and when R1 is a hydrogen atom, R2 is an aryl group which may have substituents. When R2 is a phenyl group which may have substituents, the max. sensitivity and durability characteristics can be obtd.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus equipped with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide and zinc oxide have been widely used as electrophotographic photoreceptors. An electrophotographic photoreceptor using an organic photoconductive substance has a good film-forming property and can be produced by coating, so that it has an advantage of being able to provide an electrophotographic photoreceptor having extremely high productivity and low cost. Further, it has an advantage that the color sensitivity can be freely controlled by selecting a dye or a pigment to be used, and thus extensive studies have been made so far. Particularly recently, by the development of a function-separated photoreceptor in which a charge generation layer containing an organic photoconductive dye or pigment and a charge transport layer containing a photoconductive polymer or an organic photoconductive substance of a low molecular weight are laminated. The sensitivity and durability, which have been considered to be the drawbacks of conventional organic electrophotographic photoreceptors, have been remarkably improved.

Azo pigments have excellent photoconductivity, and since compounds having various characteristics can be easily obtained by combining amine components and coupler components, many compounds have been proposed so far. , For example, JP-A-47-3
No. 7543, No. 53-132347, No. 54-22834, No. 58-70232.
JP, JP-A-60-131539, JP, JP-A-62
-2267, JP-A-62-192748,
JP-A-63-262656, JP-A-63-158
561, JP-A-63-264762, JP-A-1-180554 and the like.

However, conventional electrophotographic photoreceptors using disazo pigments are not always sufficient in terms of sensitivity and potential stability during repeated use, and very few have been put to practical use. Only material.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel electrophotographic photosensitive member, and to provide an electrophotographic photosensitive member having practical high sensitivity characteristics and stable potential characteristics upon repeated use. An object of the present invention is to provide an electrophotographic apparatus including the electrophotographic photosensitive member.

[0006]

The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer containing an azo pigment having an organic residue represented by the general formula (1). And an electrophotographic photosensitive member. General formula (1)

[Chemical 5] In the formula, R ₁ and R ₂ are the same or different and each represents a hydrogen atom,
An alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent or R ₁ and R ₂ represents a cyclic amino group containing a nitrogen atom to which R ₂ is bonded, and Z represents an oxygen atom or a sulfur atom.

The organic residue represented by the general formula (1) will be specifically described. In the formula, R ₁ and R ₂ are hydrogen atoms,
Alkyl groups such as methyl, ethyl, propyl and butyl which may have a substituent, aralkyl groups such as benzyl, phenethyl and naphthylmethyl which may have a substituent, phenyl and diphenyl which may have a substituent. , Naphthyl, aryl groups such as anthryl, pyridyl which may have a substituent,
A heterocyclic group such as thienyl, furyl, thiazolyl, carbazolyl, dibenzofuryl, benzimidazolyl, and benzthiazolyl, or a cyclic amino group containing a nitrogen atom to which R ₁ and R ₂ optionally having a substituent are bonded in the ring, Examples of the substituent of the alkyl group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a nitro group and a cyano group, and a substituent of an aralkyl group, an aryl group and a heterocyclic group. Examples include an alkyl group such as methyl, ethyl and propyl, an alkoxy group such as methoxy and ethoxy, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, an alkylamino group such as dimethylamino and diethylamino, and a phenylcarbamoyl group. ,
Examples thereof include a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl.

The cyclic amino group containing a nitrogen atom in the ring includes pyrrolyl, pyrrolinyl, pyrrolidyl, indolyl, piperidinyl, piperazinyl, isoindolyl, carbazolyl, benzoindolyl, imidazolyl, pyrazolyl,
Cyclic amino groups derived from pyrazonilyl, oxazinyl, phenoxazinyl, benzocarbazolyl, and the like, and the substituents include methyl, ethyl, alkyl groups such as propyl, methoxy, alkoxy groups such as ethoxy, fluorine atom, chlorine atom, Examples thereof include a halogen atom such as a bromine atom and an iodine atom, a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl.

As described later, R ₁ is preferably a hydrogen atom from the viewpoint of interaction between pigment molecules due to hydrogen bonding ability. When R ₁ is a hydrogen atom, R ₂ is preferably an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent. Among them, an aryl group which may have a substituent is preferable, and particularly a phenyl group which may have a substituent,
The highest sensitivity and durability characteristics can be obtained.

Z represents an oxygen atom or a sulfur atom.

The aromatic hydrocarbon ring or aromatic heterocycle which may be bonded via a bonding group to which the organic residue represented by the general formula (1) is bonded is benzene, naphthalene, fluorene, phenanthrene, anthracene or pyrene. Hydrocarbon aromatic rings such as furan, thiophene, pyridine, indole, benzothiazole, carbazole, acridone,
Heterocyclic aromatic rings such as dibenzothiophene, benzoxazole, benzotriazol, oxadiazol, and thiazole, and those in which the above aromatic ring is bonded directly or with an aromatic group or a non-aromatic group, for example, tri Phenylamine, diphenylamine, N-methyldiphenylamine, biphenyl, ta-phenyl, binaphthyl, fluorenone, phenanthrenequinone, anthraquinone, benzanthrone, diphenyloxadiazol, phenylbenzoxazole, diphenylmethane, diphenylsulfone, diphenyl Ether, benzophenone, stilbene, distyrylbenzene, tetraphenyl-p-phenylenediamine, tetraphenylbenzidine and the like can be mentioned.

The substituent which the aromatic hydrocarbon ring or aromatic heterocycle which may be bonded via the bonding group to which the organic residue represented by the general formula (1) may have is methyl,
Alkyl groups such as ethyl, propyl, butyl, methoxy,
Alkoxy group such as ethoxy, dialkylamino group such as dimethylamino and diethylamino, halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom, nitro group, cyano group, halomethyl group and general formula (5) —N═N -Cp (In the formula, Cp is a coupler having a phenolic OH group.
And a substituted azo group represented by (which represents a residue).

Next, examples of coupler residues having a phenolic OH group will be given. General formula (6)

[Chemical 6] General formula (7)

[Chemical 7] General formula (8)

Embedded image General formula (9)

[Chemical 9] General formula (10)

[Chemical 10] General formula (11)

[Chemical 11] General formula (12)

[Chemical 12] General formula (13)

[Chemical 13] General formula (14)

Embedded image General formula (15)

[Chemical 15] General formula (16)

Embedded image General formula (17)

[Chemical 17] General formula (18)

[Chemical 18] General formula (19)

[Chemical 19]

In the above general formula, X ₁ is condensed with a benzene ring to form a naphthalene ring which may have a substituent, an anthracene ring, a carbazole ring, a benzocarbazole ring, a dibenzofuran ring, a benzonaphthofuran ring, Represents an organic group necessary for forming an aromatic hydrocarbon ring such as a fluorenone ring or an aromatic heterocycle, X ₂ is condensed with a benzene ring,
A naphthalene ring which may have a substituent, an anthracene ring,
Necessary to form an aromatic hydrocarbon ring or aromatic heterocycle such as carbazole ring, benzocarbazole ring, dibenzofuran ring, benzonaphthofuran ring, diphenylene sulfite ring, quinoline ring, isoquinoline ring, acridine ring Represents an organic residue.

R ₃ and R ₄ are the same or different and each is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl which may have a substituent. Group, a heterocyclic group which may have a substituent, or R ₃ and R ₄
Of R ₅ and R ₆ are the same or different and each is a hydrogen atom, an alkyl group which may have a substituent, or an aralkyl which may have a substituent. Represents a group, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, and R ₇ represents an alkyl group which may have a substituent, and a substituent which may have a substituent. It represents a good aralkyl group, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent.

Y ₁ represents a divalent hydrocarbon group or a heterocyclic group which may have a substituent.

Contains Y ₁

Embedded image Examples include the groups listed in Table 1.

[Table 1]

Y ₂ represents a divalent aromatic hydrocarbon ring group which may have a substituent, and is o-phenylene, o-naphthylene, perinaphthylene, 1,2-anthrylene, 9,10.
Groups such as phenanthrene, Y ₃ represents a divalent aromatic hydrocarbon ring group which may have a substituent or a divalent heterocyclic group containing a nitrogen atom in the ring, and a divalent aromatic group. As the group hydrocarbon ring group, o-phenylene, o-naphthylene,
Examples thereof include groups such as perinaphthylene, 1,2-anthrylene, and 9,10-phenanthrene. The divalent heterocyclic group containing a nitrogen atom in the ring is 3,4-pyrazol-diyl,
2,3-pyridinediyl, 4,5-pyridinediyl,
Examples include groups such as 6,7-indazoldiyl, 5,6-benzimidazolediyl, and 6,7-quinolinediyl.

B represents an oxygen atom, a sulfur atom, an N-substituted or unsubstituted imino group, and the substituent of N is an alkyl group which may have a substituent or an aralkyl group which may have a substituent. Alternatively, it represents an aryl group which may have a substituent.

Z represents an oxygen atom or a sulfur atom.

Examples of the alkyl group in the above expression include groups such as methyl, ethyl, propyl and butyl, examples of the aralkyl group include groups such as benzyl, phenethyl and naphthylmethyl, and examples of the aryl group include phenyl and diphenyl. , Naphthyl, anthryl, etc., and the heterocyclic group includes pyridyl, thienyl, furyl, thiazolyl, carbazolyl, dibenzofuryl, benzimidazolyl, benzothiazolyl, etc., and a cyclic amino group containing a nitrogen atom in the ring. Is pyrrole, pyrroline, pyrrolidine, pyrrolidone, indole, indoline, isoindole, carbazole, benzoindole, imidazole.
And a group derived from pyrazole, pyrazoline, oxazine, phenoxazine, benzocarbazol and the like.

As the substituent, an alkyl group such as methyl, ethyl and propyl, an alkoxy group such as methoxy and ethoxy, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, an alkylamino such as dimethylamino and diethylamino. Group, phenylcarbamoyl group, nitro group,
Examples thereof include a cyano group and a halomethyl group such as trifluoromethyl.

Representative examples of azo pigments used in the present invention are listed in Tables 1 to 52. Pigment Examples (1) -1 to (2) -11
9, Pigment Examples (3) -1 to (3) -19, Pigment Example (4)-
1 to (4) -4 represent the azo pigment represented by the following general formula (3) as a basic type, and the organic residue portion represented by the above general formula (1) as A. General formula (3)

[Chemical 21] In the formula, R ₁ and R ₂ are the same or different and each represents a hydrogen atom,
An alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent or R ₁ and R ₂ represents a cyclic amino group containing in the ring a nitrogen atom to which R ₂ is bonded, Z represents an oxygen atom or a sulfur atom, Ar represents an aromatic group which may be bonded via a bonding group, and which may have a substituent. Represents a group hydrocarbon ring or an aromatic heterocycle, and n represents an integer of 1, 2, 3 or 4.

Pigment Examples (2) -120 to (2) -134,
Pigment Example (3) -20 to (3) -22, Pigment Example (4) -5
Is an example having an organic residue selected from the organic residues represented by the general formula (1) and an organic residue corresponding to the general formula (5) different from the selected organic residue. .

Based on the number of n, the above basic type is a type of n = 1,
It is classified into n = 2 type, n = 3 type and n = 4 type.

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

[Table 21]

[Table 22]

[Table 23]

[Table 24]

[Table 25]

[Table 26]

[Table 27]

[Table 28]

[Table 29]

[Table 30]

[Table 31]

[Table 32]

[Table 33]

[Table 34]

[Table 35]

[Table 36]

[Table 37]

[Table 38]

[Table 39]

[Table 40]

[Table 41]

[Table 42]

[Table 43]

[Table 44]

[Table 45]

[Table 46]

[Table 47]

[Table 48]

[Table 49]

[Table 50]

[Table 51]

[Table 52]

The azo pigment used in the present invention has the general formula (20).

[Chemical formula 22] (Wherein R ₁ , R ₂ and Z have the same meanings as in formula (1)) and a compound having a diazonium salt structure are coupled in the presence of an alkali to synthesize the compound. it can.

Further, the coupler component represented by the general formula (20) has a structural formula

[Chemical formula 23] And a carboxylic acid represented by the general formula (21)

[Chemical formula 24] (Wherein R ₁ and R ₂ have the same meanings as described above) and ureas represented by the formulas benzene, toluene, xylene, chlorobenzene, o
-In an aromatic solvent selected from dichlorobenzene or the like, in the presence of phosphorus trichloride, heat-condensed at 80 to 200 ° C, or a structural formula

[Chemical 25] Can be synthesized by deacetylating the compound obtained by heating the acid chloride represented by the above and the above ureas in the above aromatic solvent under acid or alkaline conditions.

Using the coupler component thus obtained, an amino compound represented by the general formula (22)

[Chemical formula 26] (Wherein Ar and n have the same meanings as in the general formula (3)) by diazotization by a conventional method, and an aqueous coupling reaction is carried out in the presence of an alkali, or the diazonium salt of the amino compound is converted into a fluoroborate salt or a zinc chloride compound. After once isolated in the form of a salt or the like, a suitable solvent, for example, an organic solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, sodium acetate, pyridine,
The azo pigment used in the present invention can be synthesized by the organic solvent-based coupling reaction in the presence of a base such as trimethylamine or triethylamine.

Further, the azo pigment (n
= 2, 3, 4), as long as it contains one organic residue represented by the general formula (1) in the same molecule, the general formula (2
3)

[Chemical 27] (Wherein Ar is as defined above, m is an integer of 1, 2 or 3 and k is an integer of 3, 2 or 1) is diazotized by a conventional method to give a diazonium salt as described above. After coupling with a coupler component represented by the formula (20) in the presence of an alkali, hydrolysis is performed with a mineral acid such as hydrochloric acid to obtain a reaction product having a structure corresponding to the following:
Structure of reaction product

[Chemical 28] (In the formula, Ar, Z, R ₁ , R ₂ , m and k are as defined above)
This reaction product may be synthesized again by diazotization by a conventional method, and then sequentially coupled with another coupler component having a phenolic OH group to synthesize the compound. Even if a diazonium salt of an amino compound represented by (22) is added to a mixed coupler solution containing at least one coupler component represented by the general formula (20) and a coupling reaction is performed in the presence of an alkali, the compound is synthesized. Of course, it is also possible to carry out the coupling reaction by primary coupling with one of the coupler components represented by the general formula (20) in the presence of an alkali and then sequentially adding an alkali-containing solution of another coupler component to carry out the coupling reaction. Can be synthesized.

Synthesis Example 1 (Synthesis of Pigment Example (2) -1) 300 ml beaker with 150 ml of water and 20 ml of concentrated hydrochloric acid.
(0.23 mol) and 7.8 g of o-dianisidine (0.
(032 mol) was added and cooled to 0 ° C., and a solution of 4.6 g (0.067 mol) of sodium nitrite in 10 ml of water was added dropwise over 10 minutes while maintaining the liquid temperature at 5 ° C. After stirring for 15 minutes, carbon filtration was carried out, and 10.5 g (0.096 mol) of sodium borofluoride was added to 90 ml of water in this solution.
The liquid dissolved in 1 was added dropwise with stirring, and the precipitated borofluoride salt was filtered, washed with cold water and then with acetonitrile, and dried under reduced pressure at room temperature. Yield 12.0g, Yield 85
%. Next, add 500 ml of N, N-dimethylformamide to a 1-liter beaker, and add 2-fodoxynaphthalene-
6-carboxylic acid-N'-phenylureido 12.9 g
After dissolving (0.042 mol) and cooling to a liquid temperature of 5 ° C, 8.8 g (0.02 mol) of the borofluoride salt obtained above was dissolved, and then 5.1 g (0.050 mol) of triethylamine was dissolved. It was dripped for 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration and washed with N, N′-dimethylformamide four times,
After washing 3 times with water, it was freeze-dried. Yield 16.7g,
Yield 95%. Elemental analysis Element Calculated value (%) Experimental value (%) C 68.3 68.6 H 4.4 4.3 N 12.8 12.7

The electrophotographic photosensitive member of the present invention has a photosensitive layer containing an azo pigment having an organic group represented by the general formula (1) on a conductive support. A preferred example of the present invention is an electrophotographic photoreceptor having a photosensitive layer functionally separated into a charge generation layer and a charge transport layer.

The charge generating layer can be formed by coating a coating solution prepared by dispersing the above-mentioned azo pigment together with a binder resin in a suitable solvent on a conductive support by a known method. It is desirable that the thin film layer has a thickness of 5 μm or less, preferably 0.1 to 1 μm.

The binder resin used in this case can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferred are polyvinyl butyral, polyvinyl benzal, polyarylate (polycondensate of bisphenol A and phthalic acid etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, poly Acrylamide, polyamide, polyvinyl pyridine, cellulose resin, polyurethane, casein, polyvinyl alcohol
And polyvinylpyrrolidone. The content of the binder resin in the charge generation layer is 80% by weight.
It is preferably 40% by weight or less.

The solvent used dissolves the above resin,
It is preferable to select from those that do not dissolve the charge transport layer and the undercoat layer described below. Specifically, alcohols such as methanol, ethanol and isopropanol, acetone,
Ketones such as methyl ethyl ketone, methyl isobutyl ketone, dichlorohexanone, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, etc. Ethers, esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, salt or methylene, dichloroethylene, carbon tetrachloride, trichloroethylene or benzene, toluene, xylene, monochlorobenzene , Aromatic compounds such as dichlorobenzene and the like can be used.

Coating is carried out by a dip coating method or a spray coating method.
Coating method, spinner coating method, bead coating method, myer coating method, blade coating method
The coating method may be a coating method such as a coating method, a roller coating method, and a curtain coating method.

Drying is preferably carried out by drying by touching at room temperature and then heat drying. Heat drying at 30 ~ 200 ℃ 5
It can be carried out in the range of from 1 minute to 2 hours while still or under blowing air.

The charge transport layer is laminated on or under the charge generation layer and has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them.

The charge transport material includes an electron transport material and a hole transport material. Examples of the electron transport material include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone,
2,4,5,7-tetranitro-9-fluorenone,
2,4,7-trinitro-9-dicyanomethylenefluorenone, 2,4,5,7-tetranitroxanthone,
Examples thereof include electron-withdrawing substances such as 2,4,8-trinitrothioxanthone and polymers obtained by polymerizing these electron-withdrawing substances. Examples of the hole transport material include pyrene, N-ethylcarbazol, N-isopropylcarbazol, N-methyl-N-phenylhydrazino-3-methylidene-9-
Ethylcarbazol, N, N-diphenylhydrazino-
3-methylidene-10-ethylphenothiazine, N, N
Hydrazone compounds such as -diphenylhydrazino-3-methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone, 1- [pyridyl ( 2)]-3- (α
-Methyl-p-diethylaminostyryl) -5- (p-
(Diethylaminophenyl) hirazoline, 1-diphenyl-3- (p-diethylaminostyryl) -4-methyl-
5- (p-diethylaminophenyl) pyrazoline, 1-
Pyrazoline compounds such as phenyl-3- (α-benzyl-p-diethylaminostyryl) -5- (p-diezulaminophenyl) pyrazoline and spiropyrazoline, 4-
Styryl compounds such as diethylamino-β-naphthylstyrene and 4-diphenylamino-4'-methoxystilbene, 2- (p-diethylaminostyryl) -6-diethylaminobenzoxazole, 2- (p-diethylaminophenyl)- 4- (p-dimethylaminophenyl)
Oxazol-based compounds such as 5- (2-chlorophenyl) oxazole, 2- (p-diethylaminostyryl)
Thiazol compounds such as -6-diethylaminobenzothiazole, bis (4-diethylamino-2-methylphenyl) -phenylmethane, 2- (N, Np-ditolyl) amino-9,9-dimethyl Triarylmethane compounds such as fluorene, 1,1-bis (4-N, N-diethylamino-2-methylphenyl) heptane, 1,1,
2,2-tetrakis (4-N, N-dimethylamino-2
-Methylphenyl) ethane and other polyarylalkanes, triphenylamine, poly-N-vinylcarbazo-
And polyvinyl pyrene, polyvinyl anthracene, polyvinyl acridine, poly-9-vinyl anthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin and the like. In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used. Further, these charge transport substances can be used alone or in combination of two or more.

When the charge transport material has no film forming property, a film can be formed by selecting an appropriate binder. Resins that can be used as the binder include, for example, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone. Insulating resins such as polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-M-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Since the charge transport layer has a limit for transporting charge carriers, the film thickness cannot be increased more than necessary. Generally 5 to 30 μm, preferably 10 to 25
μm. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

The photosensitive layer having a laminated structure of a charge generating layer and a charge transport layer is provided on a conductive support. As the conductive support on which the photosensitive layer is formed, for example, aluminum,
Aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum and the like can be used. In addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-oxidation can be used. Plastic (for example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.) having a layer formed by coating a tin alloy or the like by a vacuum deposition method, conductive particles (for example, aluminum powder, titanium oxide, oxidation) Tin, zinc oxide, carbon black, silver particles, etc.) together with a suitable binder resin on a plastic or the above-mentioned conductive support, a support or conductive polymer in which conductive particles are impregnated in plastic or paper.
It is possible to use a plastic or the like having.

An undercoat layer having a barrier function and an adhesive function may be provided between the conductive support and the photosensitive layer. The film thickness of the undercoat layer is 0.1 μm to 10 μm, preferably 0.1 μm.
5 to 5 μm is suitable. The undercoat layer is casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane,
It can be formed of aluminum oxide or the like.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned azo pigment and a charge transport material in the same layer. In this example, a charge transfer complex compound composed of poly-N-vinylcarbazole and trinitrofluorenone can be used instead of the charge transport material. In this case, the azo pigment and the charge transfer complex compound described above are dispersed in a polyester solution dissolved in tetrahydrofuran and then formed into a film.

Any electrophotographic photoreceptor contains at least one pigment selected from the azo pigments having an organic residue represented by the general formula (1) used, and its crystalline form is amorphous. It may be present or crystalline, and if necessary, pigments having different light absorption may be used in combination to enhance the sensitivity of the photoconductor or to obtain a panchromatic photoconductor. It is also possible to use two or more kinds of azo pigments having an organic residue represented by the above) or to use them in combination with a known charge generating substance.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in digital electrophotographic copying machines, laser beam printers, CRT printers, LED printers, liquid crystal printers, laser plate making, etc. It can also be widely used in many electrophotographic application fields of digital recording systems using the near infrared light source.

The present invention also comprises an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention.

Next, an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention will be described. FIG. 1 shows a schematic structure of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image bearing member, which is rotationally driven around a shaft 1a in a direction of an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged at its peripheral surface by a charging unit 2 at a predetermined positive or negative potential in the course of its rotation, and then at an exposure unit 3 an optical image exposure L (slit exposure Laser beam scanning exposure). As a result, electrostatic latent images corresponding to the exposed image are sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 from a paper feeding portion (not shown) between the photosensitive body 1 and the transfer means 5. Then, the images are sequentially transferred onto the surface of the transfer material 9 that is fed in synchronization with the above. The transfer material 9 that has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 where it is subjected to image fixing and printed out as a copy (copy). After the image transfer, the surface of the photoconductor 1 is cleaned by the cleaning means 6 to remove the residual toner after transfer, and is discharged by the pre-exposure means 7 to be repeatedly used for image formation. As a uniform charging means 2 for the photoconductor 1, a corona charging device is generally widely used. Also, as the transfer device 5, corona transfer means is generally widely used. As an electrophotographic apparatus, a plurality of constituent elements such as the photoconductor, the developing unit, and the cleaning unit described above are integrally combined as an apparatus unit, and the unit is detachably attached to the apparatus main body. It may be configured.
For example, the photosensitive member 1 and the cleaning means 6 may be integrated into one device unit, and the device body may be detachable by using a guide means such as a rail. At this time, the above-mentioned apparatus unit may be configured with a charging means and / or a developing means. Also, light image exposure L
When the electrophotographic apparatus is used as a copying machine or a printer, reflected light or transmitted light from the original is used, or the original is read and converted into a signal, and the laser beam is scanned by this signal. , The light emitting diode array is driven, or the liquid crystal shutter array is driven.

[0048]

【Example】

Amino compounds shown in Examples 1 to 18 A solution prepared by dissolving 5 g of methoxymethylated nylon (average molecular weight 32000) and 10 g of alcohol-soluble copolymerized nylon (average molecular weight 29000) in 95 g of methanol on an aluminum substrate was used. The film thickness after coating with a bar and drying is 1
An undercoat layer of μm was formed.

Next, 5 g of the pigment of Pigment Example (2) -1 was added to a solution prepared by dissolving 2 g of butyral resin (butyralization degree: 63 mol%) in 95 g of cyclohexanone, and the mixture was mixed with a sand mill to obtain 2
Dispersed for 0 hours. This dispersion was applied onto the undercoat layer with a Meyer bar so that the film thickness after drying was 0.2 μm, to form a charge generation layer.

Then, 5 g of a compound having the following structural formula

[Chemical 29] And polymethylmethacrylate (number average molecular weight 10,000
0) 5 g was dissolved in 35 g of chlorobenzene, and this solution was applied on the charge generation layer with a Mayer bar so that the film thickness after drying was 22 μm to form a charge transport layer. A photoconductor was created.

Example 2 Except for using the pigment of another pigment example instead of the pigment example (2) -1, Example 2
Electrophotographic photoreceptors corresponding to Nos. 18 to 18 were prepared.

Each of the prepared electrophotographic photosensitive members was negatively charged by a corona discharge of -5 KV using an electrostatic copying paper tester (SP-428) manufactured by Kawaguchi Electric Co., Ltd., and was left for 1 second in a dark place. It was exposed to light having an illuminance of 10 lux using a lamp and the charging characteristics were evaluated. As the charging characteristics, the surface potential V ₀ and the exposure amount E _1/2 required for the surface potential after being left in the dark to be attenuated to _1/2 were measured. The results are shown in Table 53.

[Table 53]

Comparative Examples 1 to 5 Comparative Examples 1 to 5 were made in the same manner as in Example 1 except that the pigment of the example (2) -1 used in Example 1 was replaced with the pigment of the disazo pigment example having the following structural formula. Electrophotographic photoreceptors corresponding to Examples 1 to 5 were prepared and the charging characteristics were evaluated in the same manner. The results are shown in Table 5.
4 shows. Comparative pigment A

[Chemical 30] Comparative pigment B

[Chemical 31] Comparative pigment C

[Chemical 32] Comparative pigment D

[Chemical 33] Comparative pigment E

Embedded image

[0054]

[Table 54]

From these results, it is known that each of the electrophotographic photoreceptors of the present invention has sufficient charging ability and excellent sensitivity.

Examples 19 to 30 The electrophotographic photosensitive member prepared in Example 1 is equipped with a -6.5 KV corona charger, an exposure optical system, a developing device, a transfer charger, a static elimination exposure optical system and a cleaner. It was attached to the cylinder of the electrophotographic copying machine.

The initial dark portion potential V _D and the light portion potential _VL are set to around -700 V and -200 V, respectively, and the variation amount ΔV _D of the dark portion potential and the variation amount of the bright portion potential when repeatedly used 5,000 times. ΔV _L was measured. The results are shown in Table 55. In addition,
A negative sign in the amount of change in potential represents a decrease in the absolute value of the potential, and a positive sign represents an increase in the absolute value of the potential.

Examples 2, 3, 4, 5, 8, 10, 11,
The electrophotographic photoconductors prepared in Nos. 13, 16, 17 and 18 were also evaluated in the same manner. The results are shown in Table 55.

[Table 55]

Comparative Examples 6 to 10 The electrophotographic photoreceptors prepared in Comparative Examples 1 to 5 were subjected to the same method as in Example 19 to measure the amount of potential fluctuation during repeated use. The results are shown in Table 56.

[Table 56]

From the results of Examples 19 to 30 and Comparative Examples 6 to 10, it is known that the electrophotographic photosensitive member of the present invention has little potential fluctuation during repeated use.

Example 31 Polyvinyl alcohol having a film thickness of 0.5 μm on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.
An undercoat layer was formed. Then, the same dispersion liquid of the azo pigment as in Example 1 was applied and dried with a Mayer bar,
A charge generation layer having a thickness of 0.2 μm was formed. Then, 5 g of a compound having the following structural formula

Embedded image And polycarbonate (weight average molecular weight 55000) 5 g
Was dissolved in 40 g of tetrahydrofuran and applied on the charge generation layer and dried to form a charge transport layer having a film thickness of 18 μm to prepare an electrophotographic photoreceptor.

The charging characteristics and durability characteristics of the electrophotographic photosensitive member thus prepared were measured by the same methods as in Examples 1 and 19. The results are shown. _{V 0: -700V, E 1/2:} 1.50lux · sec △ V D: + 5V, △ V L: + 5V

Example 32 Polyvinyl alcohol having a thickness of 0.7 μm on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.
An undercoat layer was formed. On this, the same dispersion liquid of the azo pigment as in Example 4 was applied and dried with a Mayer bar,
A charge generation layer having a thickness of 0.18 μm was formed. Then, 5 g of a compound having the following structural formula

Embedded image And polycarbonate (weight average molecular weight 55000) 5 g
Was dissolved in 40 g of tetrahydrofuran and applied on the charge generation layer and dried to form a charge transport layer having a film thickness of 19 μm, thereby preparing an electrophotographic photoreceptor.

The charging characteristics and durability characteristics of the produced electrophotographic photosensitive member were measured by the same methods as in Example 1 and Example 19. The results are shown. _{V 0: -700V, E 1/2:} 1.18lux · sec △ V D: 0V, △ V L: + 5V

Example 33 Example 11 was repeated except that the charge generation layer and the charge transport layer in the electrophotographic photosensitive member prepared in Example 11 were coated in the reverse order.
An electrophotographic photosensitive member was prepared in the same manner as in 1. and the charging property was evaluated by the same method as in Example 1. However, the charging was positive. The results are shown. V ₀ : + 700V, E _1/2 : 2.15lux · sec

Example 34 A charge generation layer was formed in the same manner as in Example 16, and 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2, were formed on the charge generation layer. Two
A solution prepared by dissolving 5 g of propane carbonate (molecular weight 300,000) in 50 g of tetrahydrofuran was used as a Mayer bar.
Was coated and dried to form a charge transport layer having a thickness of 22 μm to prepare an electrophotographic photosensitive member, and the charging property was evaluated by the same method as in Example 1. However, the charging was positive. The results are shown. V ₀ : + 695V, E _1/2 : 1.58lux · se
c

Example 35 0.5 g of the pigment of Pigment Example (3) -1 was dispersed with 9.5 g of cyclohexanone in a paint shaker for 5 hours. 5 g of the charge transport material used in Example 1 and polycarbonate
A solution prepared by dissolving 5 g of the above in 40 g of tetrahydrofuran was added, and the mixture was further shaken for 1 hour. The prepared coating solution was applied on an aluminum substrate with a Mayer bar and dried to form a photosensitive layer having a film thickness of 20 μm to prepare an electrophotographic photosensitive member, and the charging property was evaluated by the same method as in Example 1. However, the charging was positive. The results are shown. V ₀ : +700 V, E _1/2 : 2.35
lux / sec

[0068]

The electrophotographic photoreceptor of the present invention contains the azo pigment having a specific structure in the photosensitive layer.
One or both of the charge carrier generation efficiency and the injection efficiency inside the photosensitive layer are improved, and a remarkable effect is obtained in that sensitivity and potential stability during repeated use can be obtained. This effect is the same when the electrophotographic photosensitive member is applied to an electrophotographic apparatus.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoconductor as an image carrier (electrophotographic photoconductor of the present invention) 1a axis 2 corona charging device 3 exposure unit 4 developing unit 5 transfer unit 6 cleaning unit 7 pre-exposure unit 8 image fixing unit 9 image transfer unit Transfer material received L light image exposure

Claims (11)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains an azo pigment having an organic residue represented by the general formula (1). body. General formula (1) In the formula, R ₁ and R ₂ are the same or different and each represents a hydrogen atom,
An alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent or R ₁ and R ₂ represents a cyclic amino group containing a nitrogen atom to which R ₂ is bonded, and Z represents an oxygen atom or a sulfur atom. 2. The electrophotographic photoreceptor according to claim 1, wherein the organic residue represented by the general formula (1) is an organic residue group represented by the general formula (2). General formula (2) In the formula, R ₃ represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent, and Z represents an oxygen atom or a sulfur atom. Represents 3. The electrophotographic photoreceptor according to claim 2, wherein in the organic residue represented by the general formula (2), R ₃ is an aryl group which may have a substituent. 4. The electrophotographic photosensitive member according to claim 2, wherein in the organic residue represented by the general formula (2), R ₃ is a phenyl group which may have a substituent. 5. The aromatic hydrocarbon ring which may have a substituent which may be bonded to the organic residue represented by the general formula (1) via a bonding group, in the azo pigment according to claim 1. The electrophotographic photosensitive member according to claim 1, which has a bonded structure. 6. The azo pigment according to claim 1 is bonded to an aromatic heterocycle which may have a substituent which may be bonded to the organic residue represented by the general formula (1) via a bonding group. The electrophotographic photosensitive member according to claim 1, which has the structure described above. 7. The electrophotographic photosensitive member according to claim 1, wherein the azo pigment according to claim 1 is an azo pigment represented by the general formula (3). General formula (3) In the formula, R ₁ and R ₂ are the same or different and each represents a hydrogen atom,
An alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent or R ₁ and R ₂ represents a cyclic amino group containing in the ring a nitrogen atom to which R ₂ is bonded, Z represents an oxygen atom or a sulfur atom, Ar represents an aromatic group which may be bonded via a bonding group, and which may have a substituent. Represents a group hydrocarbon ring or an aromatic heterocycle, and n represents an integer of 1, 2, 3 or 4. 8. The electrophotographic photoreceptor according to claim 1, wherein the azo pigment according to claim 1 is an azo pigment represented by the general formula (4). General formula (4) In the formula, R ₃ represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent, and Z represents an oxygen atom or a sulfur atom. Represents an aromatic hydrocarbon ring optionally having a substituent or an aromatic heterocycle optionally having a substituent, and n is 1, 2 Represents an integer of 3 or 4. 9. The electrophotographic photosensitive member according to claim 8, wherein in the azo pigment represented by the general formula (4), R ₃ is an aryl group which may have a substituent. 10. The electrophotographic photosensitive member according to claim 8, wherein in the azo pigment represented by the general formula (4), R ₃ is a phenyl group which may have a substituent. 11. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1. [0001]