JPH07120055B2 - Electrophotographic photoreceptor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor containing an azo pigment having a specific molecular structure in a photosensitive layer. It is about.

[Conventional technology]

BACKGROUND ART Conventionally, pigments and dyes exhibiting photoconductivity have been announced in many documents.

For example, "RCA Review" Vol.23, P.413 ~ P.419 (1962.9)
Discloses the photoconductivity of a phthalocyanine pigment, and an electrophotographic photoreceptor using this phthalocyanine pigment is disclosed in US Pat. No. 3397086 and US Pat. No. 38161.
It is shown in Japanese Patent Publication No. 18 and the like. Other organic semiconductors used in electrophotographic photoreceptors include, for example, US Pat. No. 431598.
No. 3, U.S. Pat. No. 4,327,169 and "Reseach Disclo".
sure "20517 (1981.5), pyrylium-based dye, squaric acid methine dye shown in US Pat. No. 3824099, US Pat. No. 3898084, US Pat. No. 4251613, US Pat. No. 4582771. Examples thereof include disazo pigments disclosed in Japanese Patent Publication No.

Such an organic semiconductor is easier to synthesize than an inorganic semiconductor, and can be synthesized as a compound having photoconductivity with respect to light in a required wavelength range. The electrophotographic photosensitive member formed on the conductive support has an advantage that the color sensitivity is improved, but practical properties are still insufficient in terms of sensitivity, durability and the like.

[Problems to be solved by the invention]

An object of the present invention is to provide a novel photoconductive material.

Another object of the present invention is to provide an electrophotographic photosensitive member which can be used in all existing electrophotographic processes and has practically high sensitivity characteristics and stable potential characteristics upon repeated use.

A second object of the present invention is to provide an electrophotographic photosensitive member having a wide spectral sensitivity extending from the visible region to the near infrared region and the infrared region.

[Means for solving problems]

That is, the electrophotographic photoreceptor of the present invention is characterized in that the photosensitive layer contains a compound having a bonding group represented by the general formula (1) or (2) in the structural formula.

Where R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atom, fluorine, chlorine, bromine,
Halogen atom such as iodine, cyano group, halomethyl group such as trifluoromethyl and difluoromethyl, acyl group such as acetyl, propionyl, benzoyl, toluoyl and cinnamoyl, alkyloxycarbonyl group such as methoxycarbonyl, ethoxycarbonyl and butoxycarbonyl, Shows aryloxycarbonyl groups such as enoxycarbonyl and naphthyloxycarbonyl, alkyl groups such as methyl, ethyl, propyl and butyl, aralkyl groups such as benzyl, phenethyl and naphthylmethyl, or aryl groups such as phenyl, naphthyl, biphenyl and anthryl. . The above acyl group, alkyloxycarbonyl group, aryloxycarbonyl group, alkyl group, aralkyl group,
The aryl group may have a substituent. The types of substituents include halogen atoms such as fluorine, chlorine, bromine and iodine, nitro groups, cyano groups, halomethyl groups such as trifluoromethyl and difluoromethyl, acyl groups such as acetyl and benzoyl, methyl, ethyl, propyl, Examples thereof include alkyl groups such as butyl, aralkyl groups such as benzyl and phenethyl, and aryl groups such as phenyl, naphthyl and biphenyl.

The present invention can be achieved by incorporating a dye, a pigment or the like having the above-mentioned bonding group in the structural formula into the photosensitive layer. In particular, an azo pigment represented by the following general formula (3) or (4) is used. When it is contained in the photosensitive layer, its effect is remarkable.

Here, R ₁ , R ₂ , R ₃ and R ₄ are synonymous with the above symbols, and Ar ₁ and A
r ₂ , Ar ₃ and Ar ₄ are divalent aryl groups such as phenylene, biphenylene and naphthalenediyl, or pyridine, quinoline,
A divalent heterocyclic group formed by removing two hydrogen atoms from a heterocycle such as carbazole, thiophene, benzoxazole, benzothiazole, benzotriazole and indole is shown. These divalent aryl group and heterocyclic group may have a substituent. Substituents include halogen atoms such as fluorine, chlorine, bromine and iodine, methyl, ethyl,
Alkyl groups such as propyl and butyl, alkoxy groups such as methoxy, ethoxy and butoxy, phenyl, naphthyl,
An aryl group such as biphenyl, a nitro group, a cyano group, a trifluoromethyl group and the like are used.

Cp ₁ , Cp ₂ , Cp ₃ and Cp ₄ in the general formula (3) or (4) represent coupler residues having a phenolic OH group, and Cp ₁ and Cp ₂ and Cp ₃
And Cp ₄ may be the same or different. C
More preferable specific examples of the coupler residue represented by p ₁ , Cp ₂ , Cp ₃ and Cp ₄ are represented by formulas (5) to (10).

In the formula, X is condensed with a benzene ring to form a polycyclic aromatic ring such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, dibenzonaphthofuran ring, diphenylene sulphite ring, or a heterocyclic ring. The required residues are shown below.

The ring to which X is bonded is more preferably a naphthalene ring, an anthracene ring, a carbazole ring, or a benzcarbazole ring.

In the formula, R ₅ and R ₆ represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group, a heterocyclic group or a cyclic amino group together with the nitrogen atom to which R ₅ and R ₆ are bonded. .

Specific examples of the alkyl group include methyl, ethyl, propyl, butyl and the like, specific examples of the aralkyl group include benzyl, phenethyl, naphthylmethyl and the like, and specific examples of the aryl group include phenyl, diphenyl, naphthyl, anthryl and the like, Specific examples of the heterocyclic group include carbazole,
Examples include dibenzofuran, benzimidazolone, benzthiazole, thiazole, pyridine and the like.

Specific examples of the cyclic amino group include pyrrolidino, piperazino, morpholino, 9-carbazolyl and the like.

In the formula, R ₇ and R ₈ represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group or an aralkyl group. Specific examples of R ₇ and R ₈ are the same as those of R ₅ and R ₆ .

In the formula, the alkyl group, aryl group, aralkyl group, alkoxy group and heterocyclic group represented by the substituents R _{5 to} R ₈ are other substituents such as halogen atom such as fluorine, chlorine, iodine and bromine, methyl and ethyl. Substituted with alkyl group such as propyl, isopropyl, butyl, alkoxy group such as methoxy, ethoxy, propoxy, phenoxy, etc., substituted amino group such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, pyrrolidino It may have been done.

In the formula, Y represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group containing a nitrogen atom in the ring.

As the divalent group of the aromatic hydrocarbon, a divalent group of a monocyclic aromatic hydrocarbon such as o-phenylene, a condensed polycondensation group such as o-naphthylene, perinaphthylene, 1,2-anthrylene, and 9,10-phenanthrylene. A divalent group of a cyclic aromatic hydrocarbon may be mentioned. Further, as the divalent group of the hetero ring containing a nitrogen atom in the ring, 3,4-pyrazolediyl group, 2,3-pyridinediyl group, 4,5-pyrimidinediyl group, 6,7-indazolediyl group, A divalent group such as a 6,7-quinolinediyl group may be mentioned.

R ₉ in the formula represents an aryl group or heterocyclic group which may have a substituent, and specifically represents a phenyl, naphthyl, anthryl, bienyl, pyridyl, thienyl, furyl or carbazolyl group.

As the substituent of the aryl group or heterocyclic group represented by R ₉ , halogen atoms such as fluorine, chlorine, iodine and bromine, alkyl groups such as methyl, ethyl, propyl, isopropyl and butyl, methoxy, ethoxy, propoxy, phenoxy and the like. Alkoxy group, nitro group, cyano group, dimethylamino,
Substituted amino groups such as dibenzylamino, diphenylamino, morpholino, piperidino, pyrrolidino and the like can be mentioned.

In the formula, R ₁₀ and R ₁₁ represent an alkyl group which may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group, and specifically methyl, ethyl, propyl, butyl, benzyl, phenethyl, naphthyl It shows methyl, phenyl, naphthyl, anthryl, diphenyl, carbazole, dibenzofuran, benzimidazolone, benzthiazole, thiazole and pyridine.

In the formula, the substituents of the alkyl group, aryl group, aralkyl group and heterocyclic group represented by R ₁₀ and R ₁₁ are halogen atoms such as fluorine, chlorine, iodine and bromine, methyl, ethyl, propyl, isopropyl and butyl. Alkyl group of methoxy,
Alkoxy groups such as ethoxy, propoxy and phenoxy,
Substituted amino groups such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, pyrrolidino and the like can be mentioned.

X in general formulas (9) and (10) has the same meaning as in general formula (5). When Cp ₁ , Cp ₂ , Cp ₃ and Cp ₄ have the structures represented by the above general formulas (5) to (10), the effect of the present invention is remarkable, but Cp ₁ and Cp
p ₂ , Cp ₃ and Cp ₄ do not necessarily have the same structure.

Next, a general method for producing the azoalkene or disazoalkene compound used in the present invention will be described. The compound having the linking group represented by the general formula (1) or (2) in the structural formula is, for example, Chemische Berichte 102 Vol.
7-3655, or Justus Liebiys Annolender C, 1971
hemie 745, pp. 193-203, that is, a method of forming N-ylide using pyridine as a medium and then reacting it with a diazonium salt, or in 1986, the Chemical Society of Japan Spring Annual Meeting (April). It is synthesized by the method shown in “Synthesis of Ylide Containing Arylazo Group and Its Utilization” published by the inventors, that is, a method of reacting with a diazonium salt using S-ylide or P-ylide.

The manufacturing method for the azoalkene compound has been described above.
As described above, the azo pigment represented by the general formula (3) or (4) is particularly effective.

Hereinafter, a general method for producing the azo pigment used in the present invention will be described. In the azo pigment represented by the general formula (3) or (4), when Cp ₁ and Cp ₂ or Cp ₃ and Cp ₄ are the same, general formula (12)
Alternatively, the diamine represented by (13) is converted to a detrazonium salt by a conventional method such as sodium nitrite or nitrosylsulfate, and the coupler component Cp ₁ or Cp ₃ is subjected to aqueous coupling, or [The symbols Ar ₁ , Ar ₂ , Ar ₃ , Ar ₄ , R ₁ , R ₂ , R ₃ and R ₄ are the same as the symbols in claim 2. Alternatively, it can be obtained by taking out the obtained tetrazonium salt with a stable salt such as a borofluoride salt, and then performing coupling in an organic solvent such as DMF. When Cp ₁ and Cp ₂ or Cp ₃ and Cp ₄ are different from each other, in the coupling reaction, first coupling with the first coupler component is performed, and then a monoazo body is coupled, followed by coupling with the second coupler component to obtain a disazo pigment. Alternatively, it can be obtained by mixing two coupler components and conducting a coupling reaction, but the former method is preferable for surely obtaining an asymmetric pigment.

Next, specific examples of the azoalkene compound used in the present invention are listed below. However, the compounds shown in the following specific examples do not limit the claims of the present invention.

The coating film containing the above-mentioned azoalkene compound exhibits photoconductivity, and therefore can be used for the photosensitive layer of the electrophotographic photoreceptor described below.

That is, in the specific examples of the present invention, the electrophotographic photoreceptor is prepared by forming a film on the conductive support by the vacuum deposition method or by forming a film by dispersing and containing it in an appropriate binder. can do.

In a preferred embodiment of the present invention, the above-mentioned photoconductive coating can be applied as a charge generation layer in an electrophotographic photoreceptor in which the photosensitive layer of the electrophotographic photoreceptor is functionally separated into a charge generation layer and a charge transport layer.

The charge generation layer contains as much of the above-mentioned photoconductive compound as possible in order to obtain sufficient absorbance, and is a thin film layer, for example 5 μm or less, in order to shorten the range of the generated charge carrier. Is preferably a thin film layer having a film thickness of 0.01 to 1 μm. This means that most of the amount of incident light is absorbed by the charge generation layer to generate a large number of charge carriers, and the generated charge carriers are not deactivated by recombination or capture (trap) to the charge transport layer. It is due to the need to inject.

The charge generation layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on a conductive support, or can be obtained by forming a vapor deposition film by a vacuum vapor deposition device. The binder that can be used when forming the charge generation layer by coating 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. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinyl pyridine, cellulosic resin, urethane Insulating resins such as resins, epoxy resins, casein, polyvinyl alcohol and polyvinylpyrrolidone can be mentioned. The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins differs depending on the type of resin, and is preferably selected from those that do not dissolve the charge transport layer and the undercoat layer described below. Specific organic solvents include methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexanone, N, N-dimethylformamide, amides such as N, N-dimethylacetamide, and dimethyl sulfoxide. Ethers such as sulfoxides, tetrahydrofuran, dioxane and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride and trichloroethylene. Or benzene, toluene,
Aromatic compounds such as xylene, ligroin, monochlorobenzene, and dichlorobenzene can be used.

The coating can be carried out using a coating method such as a dip coating method, a spray coating method, a blade coating method, a roller coating method, a curtain coating method and the like.

Drying is preferably a method of drying by touching at room temperature and then drying by heating. Heat drying at a temperature of 30 ℃ to 200 ℃ for 5 minutes to 2
It can be performed statically or under blast for a time range of hours.

The charge transport layer is electrically connected to the above-mentioned charge generation layer, and has a function of receiving the charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. At this time, the charge transport layer may be laminated on or below the charge generation layer.

The charge-transporting substance in the charge-transporting layer includes an electron-transporting substance and a hole-transporting substance, and the electron-transporting substance includes 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, 2,
There are electron-withdrawing substances such as 4,8-trinitrothioxanthone and those obtained by polymerizing these electron-withdrawing substances.

As the hole transporting substance, pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-Phenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-10-ethylphene Nothiazin,
N, N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N, N-
Diphenylhydrazone, 1,3,3-trimethylindolenine-ω-aldehyde-N, N-diphenylhydrazone, p
-Hydrazones such as diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1-phenyl-3- ( p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (3)]-3- (p-Diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [Lepidil (2)]-3- (p-
Diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3-
(Α-Methyl-p-diethylaminostyryl) -5-
(P-diethylaminophenyl) pyrazoline, 1-phenyl-3- (p-diethylaminostyryl) -4-methyl-5- (p-diethylaminophenyl) pyrazoline,
Pyrazolines such as 1-phenyl-3- (α-benzyl-p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline and spiropyrazoline, 2-
(P-Diethylaminostyryl) -6-diethylaminobenzoxazole, 2- (p-diethylaminophenyl) -4- (p-dimethylaminophenyl) -5- (2
-Chlorophenyl) oxazole and other oxazole compounds, 2- (p-diethylaminostyryl) -6-diethylaminobenzothiazole and other thiazole compounds,
Triarylmethane compounds such as bis (4-diethylamino-2-methylphenyl) -phenylmethane, 1,1-
Polyarylalkanes such as bis (4-N, N-diethylamino-2-methylphenyl) heptane and 1,1,2,2-tetrakis (4-N, N-dimethylamino-2-methylphenyl) ethane, p-diphenylamino -Β-phenylstilbene, p-ditolylaminostyrylfluorenylidene, p-diethylaminostyrylbenzene, p-diethylaminostyryl-4-methoxynaphthalene, 3-α-
Styryl compounds such as phenylstyryl-9-ethylcarbazole, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin, etc. There is.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-telluramorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have a film forming property, a film can be formed by selecting an appropriate binder. The resin that can be used as the binder is, for example, an acrylic resin,
Polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber, or organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene You can

Since the charge transport layer has a limit for transporting the charge carrier, the film thickness cannot be increased more than necessary. Generally, it is 5 to 30 μm, but the preferable range is 8 to 20 μm.
Is. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

The photosensitive layer having such a laminated structure of the charge generation layer and the charge transport layer is provided on the conductive support. As the conductive support, one having conductivity itself, for example, aluminum, aluminum alloy, copper, zinc, stainless steel,
Vanadium, molybdenum, chrome, titanium, nickel,
Indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloy, indium oxide,
Plastic having a layer formed by vacuum deposition of tin oxide, indium oxide-tin oxide alloy, or the like, conductive particles (for example, titanium oxide, tin oxide, carbon black, silver particles, etc.) together with a suitable binder. It is possible to use a support coated on the conductive support, a plastic in which conductive particles are impregnated, a support in which paper is impregnated, or a plastic having a conductive polymer.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The subbing layer is made of casein, polyvinyl alcohol, nitrocermoose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. Can be formed.

The thickness of the undercoat layer is 0.1 to 5 μm, preferably 0.5 to 3 μm
Is appropriate.

In another embodiment of the present invention, the above-mentioned hydrazones,
Organic photoconductive substances such as pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamine, poly-N-vinylcarbazoles and inorganic photoconductive substances such as zinc oxide, cadmium sulfide and selenium A photosensitive film containing the above compound as a sensitizer for the substance can be used. This photosensitive film is formed by coating these photoconductive substances and the above compounds with a binder.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned azoalkene compound in the same layer together with a charge transporting substance. In this case, a charge transfer complex compound composed of poly-N-vinylcarbazole and trinitrofluorenone can be used in addition to the above charge transport material. The electrophotographic photoreceptor of this example can be prepared by dispersing the above-mentioned azoalkene compound and charge transfer complex compound in a solution of polyester dissolved in tetrahydrofuran and then forming a film.

In any of the photoconductors, the charge generating substance contains at least one kind of dye or pigment selected from the compounds having a bonding group represented by the structural formula (1) or (2), and its crystalline form is amorphous. Or may be crystalline.
If necessary, pigments having different light absorption may be used in combination to enhance the sensitivity of the photoconductor, or two or more azoalkene compounds according to the present invention may be combined for the purpose of obtaining a bankromatic photoconductor. Alternatively, it may be used in combination with a charge generating substance selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in laser printers, CRT printers, and LEDs.
It can be widely used in electrophotographic application fields such as printers, liquid crystal printers, and laser plate making.

Hereinafter, the present invention will be described with reference to examples.

Examples 1 to 58 An aqueous ammonia solution of casein (11.2% casein, 1 g of ammonia water, 222 ml of water) was applied on an aluminum support with a Meyer bar so that the film thickness after drying was 1.0 μm and dried.
Next, 5 g of the above-mentioned No. (1) compound was added to 95 m of ethanol.
2 g of butyral resin (butyralization degree: 75 mol%) was dissolved in l and dispersed in a sand mill for 2 hours. This dispersion has a film thickness of 0.5 after being dried on the casein layer previously formed.
The charge generation layer was formed by coating with a Meyer bar so as to have a thickness of μm and drying. Then the structural formula Hydrazone compound (5 g) and polymethylmethacrylate resin (number average molecular weight 100,000) (5 g) are dissolved in 70 ml of benzene, and this is applied to the charge generation layer with a Meyer bar so that the film thickness after drying is 18 μm and dried. A charge transport layer was formed to prepare a photoconductor of Example 1. Photosensitive members of Examples 2 to 58 were prepared in the same manner as in Example 1 by using the other exemplified pigments shown in Table 1 in place of the compound of Example No. (1).

The electrophotographic photoconductor thus prepared is manufactured by Kawaguchi Electric Co., Ltd.
Using an electrostatic copying paper tester Model SP-428, a static method was used to perform corona charging at −5 KV, hold for 1 second in a dark place, and then expose at 2 lux of illuminance to examine charging characteristics.

As the charging characteristics, the surface potential (Vo) and the exposure dose (E 1/2) required to reduce the potential when dark-decayed for 1 second to 1/2 were measured. The results are shown in Table 1.

Comparative Examples 1 to 4 The electrophotographic characteristics of the pigment having the following structure were evaluated in the same manner as in Example 1 and are shown in Table 2.

As is clear from the table, the pigment according to the present invention is significantly superior to the comparative example.

Examples 59 to 63 Using the photoconductors used in Examples 1, 26, 37, 52 and 58, changes in the light potential and the dark potential during repeated use were measured. As a method, -5.6KV corona charger, exposure optical system, developing device,
This copying machine, in which a photoconductor is attached to a cylinder of an electrophotographic copying machine equipped with a transfer charger, a static elimination exposure optical system, and a cleaner, is configured such that an image can be obtained on a transfer paper as the cylinder is driven. Using this copier, the initial bright area potential (V _L ) and dark area potential (V _D ) were −100 V and −600, respectively.
The light potential (V _L ) and the dark potential (V _D ) were measured after setting to about V and using 5000 times. The results are shown in Table 3.

Comparative Examples 5 to 8 Similar to Example 59, the potential fluctuations during repeated use of the photoconductors used in Comparative Examples 1 to 4 were examined and shown in Table 4.

From the above, it is understood that the present invention is superior in durability as compared with the comparative pigment.

Example 64 On top of the charge generation layer prepared in Example 1, 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2'-propane carbonate (molecular weight 300,0
A coating solution prepared by dissolving 5 g of 00) in 70 ml of tetrahydrofuran was applied so that the coating amount after drying would be 10 g / m ^2, and dried.

The electrophotographic photosensitive member thus prepared was subjected to charge measurement in the same manner as in Example 1. At this time, the electrode made of a strip electrode was used.
The results are shown below.

V ₀ : 675V E _{1 ] 2} : 4.0lux · sec Example 65 A polyvinyl alcohol film having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. Next, the dispersion of the azoalkene compound used in Example 1 was applied onto the polyvinyl alcohol layer previously formed by a Meyer bar so that the film thickness after drying was 0.5 μm, and dried to form a charge generation layer. .

Then the structural formula Pyrazoline compound 5g and polyarylate resin (bisphenol A and terephthalic acid-isophthalic acid condensation polymer) 5g
Was dissolved in 70 ml of tetrahydrofuran and applied on the charge generation layer so that the film thickness after drying was 10 μm and dried to form a charge transport layer. The charging property and durability property of the thus prepared photoconductor were measured by the same method as in Example 59. The results are shown in Table 3.

From the results in Table 3, the sensitivity is good and the potential stability during durable use is also good.

Example 66 An aqueous ammonia solution of casein was applied onto an aluminum support having a thickness of 100 μm and dried to form an undercoat layer having a thickness of 0.5 μm.

Next, 5 g of 2,4,7-trinitro-9-fluorenone and poly-
5 g of N-vinylcarbazole (number average molecular weight 300,000) was dissolved in 70 ml of tetrahydrofuran to form a charge transfer complex compound. This charge transfer complex compound and the above-exemplified compound No. 2
11 g of polyester resin (Vylon: Toyobo) was added to and dispersed in a solution of 5 g of tetrahydrofuran in 70 ml. This dispersion was applied on the undercoat layer and dried to prepare a 12 μm photosensitive member.

The charging characteristics and durability characteristics of the thus prepared photoconductor were measured by the same method as in Example 1. The results are shown below. However, the charging polarity was.

V ₀ : 685V E _{1 ] 2} : 3.0lux · sec Example 67 The charge transport layer and the charge generating layer of Example 1 were sequentially laminated on the casein layer of the aluminum support having the casein layer used in Example 66. A photoreceptor was formed in exactly the same manner as in Example 1 except that the layer structure was different, and the charging characteristics were measured in the same manner as in Example 1. However, the charging polarity was set. The results are shown below.

V ₀ : 680V E _{1 ] 2} : 3.5lux · sec Example 68 When the photoconductor used in Example 25 was exposed to a semiconductor laser having an oscillation wavelength of 780 nm, the spectral sensitivity at 780 nm was 0.9 μJ / cm ² (half) Exposure amount).

Next, this photoconductor was applied to the drum of a laser beam printer (LBP-CX manufactured by Canon Inc.), which is an electrophotographic printer of a reversal development system equipped with a semiconductor laser as an exposure optical system, and a real-image test was conducted. No good image was obtained. Moreover, this did not change even after repeating 10,000 times.

Example 69 In Example 68, 31,78,83,1 instead of the exemplified compound 35
A photoreceptor on a drum was prepared in the same manner except that 00 was used. The spectral sensitivity of each photoconductor at 780 nm is 4th.
It was as shown in the table.

Table 4 Exemplified Compounds 31 78 83 100 Half-exposure dose (μJ / cm ² ) 1.3 1.0 0.9 1.8 Next, a real image test was conducted in the same manner as in Example 68, and an image free from fog was obtained. This did not change after repeated 10,000 times.

〔The invention's effect〕

The present invention, by using a compound having a specific bonding group azoalkene in the structural formula in the photosensitive layer, either one or both of carrier generation efficiency or carrier transport efficiency in the photosensitive layer containing the azoalkene compound. Perhaps because of the improvement, it is possible to obtain an electrophotographic photosensitive member having high sensitivity and excellent potential stability during durable use. Further, it is possible to obtain a good image with high sensitivity and no fog even in the oscillation wavelength range of the semiconductor laser.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 58-70232 (JP, A) JP 58-217556 (JP, A) JP 61-84653 (JP, A) JP 61- 251861 (JP, A) Japanese Patent Sho 47-24892 (JP, B1)

Claims (3)

[Claims] 1. A general formula (1) or (2) (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, a halogen atom, a cyano group, a halomethyl group, or an optionally substituted acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, An electrophotographic photoreceptor comprising a compound having a bonding group represented by an alkyl group, an aralkyl group or an aryl group) in a structural formula in a photosensitive layer. 2. A compound having a bonding group represented by the general formula (1) or (2) in the structural formula is represented by the general formula (3) or (4). (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, a halogen atom, a cyano group, a halomethyl group, or an optionally substituted acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an alkyl group. Group, aralkyl group or aryl group, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ each represent a divalent aryl group or heterocyclic group which may have a substituent, and Cp ₁ , Cp ₂ and Cp. ₃ , Cp
₄ represents a coupler residue having a phenolic OH group. Cp ₁
And Cp ₂ , and Cp ₃ and Cp ₄ may be the same or different. The electrophotographic photosensitive member according to claim 1, which is an azo pigment represented by the formula (1). 3. Cp ₁ , Cp ₂ , in the general formulas (3) and (4)
The electrophotographic photosensitive member according to claim 2, wherein Cp ₃ and Cp ₄ are selected from the general formulas (5) to (10). (In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a hetero ring by condensing with a benzene ring. R ₅ and R ₆ may have a hydrogen atom or a substituent. It represents a cyclic amino group together with an alkyl group, an aryl group, an aralkyl group, a heterocyclic group, or a nitrogen atom to which R ₅ and R ₆ are bonded.) (In the formula, R ₇ represents an alkyl group which may have a substituent, an aryl group or an aralkyl group.) (In the formula, R ₈ represents an alkyl group which may have a substituent, an aryl group or an aralkyl group.) (In the formula, Y represents a divalent group of an aromatic hydrocarbon or a divalent group of a hetero ring containing a nitrogen atom in the ring.) (In the formula, R ₉ represents an optionally substituted aryl group or heterocyclic group, and X has the same meaning as X in formula (5).) (R ₁₀ and R ₁₁ represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent. X has the same meaning as X in the general formula (5).