JPS6218566A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having excellent sensitivity and potential stability in durable use by incorporating a specific tetrakis azo pigment into a photosensitive layer. CONSTITUTION:The photosensitive layer contains the tetrakis azo pigment expressed by the formula 1. The tetrakis azo pigment expressed by the formula has the structure symmetrically having four azo coupler components via N with an arylene group or bivalent condensed polycyclic arom. ring group as the center of the molecular skeleton and containing long pi-electron conjugated system and the sensitivity and the potential stability in durable use are consid ered to be assured as such structure contributes to the improvement of the photoconductivity of the pigment and the improvement of either or both of carrier forming efficiency and conveyability. The representative example of the tetrakis azo to be used is shown by the formula 1-1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor using a new electrophotographic photosensitive material, and more specifically, it relates to an electrophotographic photoreceptor using a novel electrophotographic photosensitive material. This invention relates to an electrophotographic photoreceptor contained in a layer.

[Conventional technology]

Conventionally, pigments and dyes exhibiting photoconductivity have been published in numerous publications.

For example, “RCA Revirw’ Vow, 2
3+ P, 413-P, 419 (1962, 9), the photoconductivity of phthalocyanine pigments was announced, and electrophotographic photoreceptors using this phthalocyanine pigment were published in U.S. Pat. No. 3,397,086 and U.S. Pat. 3
It is shown in 816118 and the like. In addition, examples of organic semiconductors used in electrophotographic photoreceptors include U.S. Pat. No. 4,315,983 and U.S. Pat. No. 4,327,169.
Publications and Reaeach Disclosure”2
0517 (1981°5), methine squaric acid dyes shown in U.S. Pat. No. 3,824,099, and U.S. Pat. No. 38,980.
Examples include disazo pigments disclosed in Japanese Patent No. 84, US Pat. No. 4,251,613, and the like.

Such organic semiconductors are easier to synthesize than inorganic semiconductors, and can be synthesized as compounds that have photoconductivity for light in the required wavelength range. An electrophotographic photoreceptor formed on a conductive support has the advantage of improved color sensitivity, but only a few of them are practical in terms of sensitivity and durability.

[Problem that the invention seeks to solve]

It is an object of the present invention to provide a new photoconductive material.

Another object of the present invention is to provide an electrophotographic photoreceptor that can be used in all existing electrophotographic processes and has practical high sensitivity characteristics and stable potential characteristics during repeated use. be.

[Means for solving problems]

In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate according to the present invention, the photosensitive layer has the following -, general formula (1), (wherein is a coupler residue having a phenolic OH group;
Ar1 is an arylene group or a divalent condensed polycyclic aromatic ring group which may have a substituent: Ar 2 + Ar 5 a
An electrophotographic image containing a tetrakisazo pigment represented by Ar4 and Ars each representing an arylene group, a divalent condensed aromatic ring group, or a divalent heterocyclic group, each of which may have a substituent. A photoreceptor is provided.

In the above general formula (1), the f2-residue having a phenolic OH group in A is, for example, the following general formula (2).
It is represented by ~(8): ~X,'ゝ,X,' (wherein, Alkyl, aralkyl which may have.

Aryl or heterocyclic group, or residues which together with the nitrogen atom form a cyclic amine group; R3 and R4 are alkyl, each of which may have a substituent.

Aralkyl, aryl; Y is aromatic hydrocarbon 2
A residue that forms a heterocyclic divalent group together with a valent group or a nitrogen atom; R5 and R6 are each a hydrogen atom,
Alkyl which may have a substituent.

Aralkyl, aryl, heterocyclic group, or residues that together form a 5- to 6-membered ring with the bonded carbon atom; R7 and R8 are each hydrogen atom, alkyl, aralkyl, aryl, or heterocyclic group that may have a substituent (represents a ring group)
.

Examples of the polycyclic aromatic ring and heterocycle of X include naphthalene, anthracene, carbazole, benzcarbazole, nopenzofuran, benzonaphthofuran, and diphenylene sulfide.

In the case of R,, R2, examples of alkyl include hamethyl, ethyl, f-ropyl, butyl, etc., examples of alkyl include benzyl, phenethyl, naphthylmethyl, etc., and examples of aryl include phenyl, diphenyl, naphthyl. .

Examples include Anthril. Especially R4 is hydrogen! D
%R2 Electron-absorbing group such as halo, nitro, cyan, trifluoromethyl, etc. and ethyl at the O-position.

Preferably, the compound has a structure of a phenyl group having an alkyl group such as methyl or butyl.

Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine.

Specific examples of R6 and R4 include the same ones as exemplified above for R1 and R2.

Furthermore, the alkyl group, aralkyl group, aryl group, and heterocyclic group of R1, R2, R3, and R4 described above may further include other substituents, such as the aforementioned alkyl group, alkoxy groups such as methoxy, ethoxy, and propoxy, and 710 G atoms. , nitro group,
Cyano group, or dimethylamino, zoethylamino,
It may be substituted with substituted amino groups such as dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino.

In the definition of Y, the divalent aromatic hydrocarbon group includes, for example, a monocyclic aromatic hydrocarbon group such as 0-phenylene,
0-Naphthylene, perinaphthylene.

Examples include fused polycyclic aromatic hydrocarbon groups such as 1.2-antrylene and 9.10-phenanthrylene.

An example of a divalent heterocycle formed with nitrogen is the 3,4-pyrazolediyl group.

2.5 such as 3-bilinone soil group, 4,5-pyrimidinediyl group, 6,7-indazolnoyl group, 5,6-penzimidazolediyl group, 6,7-chiralindiyl group, etc.
to 6-membered heterocyclic divalent groups.

Examples of the alkyl, aralkyl, and aryl of R5 and R6 include the same ones as exemplified for R1 to R4.

Further, the heterocyclic group for R5 and R6 is pyridyl.

Examples include chenyl, furyl, carbazoyl, and the like. These groups may be substituted with the substituents described above.

Furthermore, R5 and R6 represent residues that together form a 5-6 negative ring. The 5- to 6-membered ring may have a fused aromatic ring. Examples of such groups include cyclolinthelidene, cyclohexylidene, 9-fluorenidene, 9-xanthenylidene, and the like.

Specific examples of alkyl, aryl, and aralkyl in R7 and R8 include the same as those listed above. Heterocycles include carbazole, dibenzofuran, benzimidacylon, and benzthiazole.

Examples include thiazole and pyridine. These may be substituted with the substituents described above.

The specific example of X in formulas (7) and (8) is the same as that of X in formula (2) above. In particular, the ring to which X is bonded is an anthracene ring or a benzcarbazole ring.

A carbazole ring is preferred. The benzcarbazole ring has a large effect of expanding the spectral sensitivity range to a long wavelength range, and is suitable for producing a photoreceptor having high sensitivity in the semiconductor laser range.

In the above general formula (1), Ar1 is specifically, for example, an arylene group such as phenylene, naphthalene, anthrylene, or biphenylene; or indene, fluorene, acenaphthene, perylene, or fluorenone.

Anthrone, anthraquinone, benzanthrone.

Examples include divalent groups of condensed polycyclic aromatic rings such as isocoumarin. These arylene groups or divalent condensed polyfunctional aromatic ring groups may be substituted with substituents such as alkyl, alkoxy, aralkyl, aryl, nologne atoms, acyl, nitro, or cyano as described above.

Furthermore, Ar2 +Ar3 +A in general formula (1)
r4 and Ar5 are divalent heterocyclic groups such as pyridine, quinoline, oxadiazole, benzoxazole, benzimidazole, benzothiazole, benzotriazole, dibenzofuran, carbazole, xanthine, the above-mentioned arylene group, divalent Examples include fused polycyclic aromatic ring groups. These groups may be substituted with the substituents described above.

According to the present invention, although not bound by theory, the tetrakis pigment of the general formula (1) has an arylene group or a divalent condensed polycyclic aromatic ring group as the center of the molecular skeleton, and 4 By having a structure containing two azocabra components and a long π-electron conjugated system, the pigment's photoconductivity is improved, and either or both of carrier generation efficiency and transportability are improved, resulting in sensitivity. It is thought that potential stability during long-term use is ensured.

In addition, it achieves high sensitivity and a long wavelength spectral sensitivity range, making it possible to apply it to high-speed copiers, radar beam printers, LED printers, liquid crystal printers, etc.
Furthermore, a stable potential is ensured regardless of the previous history of the photoreceptor, and stable and beautiful images can be obtained.

Representative examples of the tetrakisazo pigments used in the present invention are listed below.

These tetrakisazo pigments can be used alone or in combination of two or more. In addition, these pigments have, for example, the general formula (wherein Ar1, Ar2+ Ar3+ Ar
4+ Ars has the same meaning as the symbol in general formula (1)) is octazotized by a conventional method, and then the corresponding coupler is hydrogen-coupled in the presence of an alkali, or the tetrazonium of the diamine is Once the salt is isolated in the form of a borofluoride salt or zinc chloride double salt, it is coupled with a coupler in the presence of an alkali in a suitable solvent such as N,N-dimethylformamide or dimethyl sulfoxide. It can be easily manufactured.

The detailed conditions for producing the above-mentioned tetrakisazo pigment will become clear from the reference examples described below.

The coating containing the tetrakisazo pigment described above exhibits photoconductivity and can therefore be used in the photosensitive layer of the electrophotographic photoreceptor described below.

That is, in a specific example of the present invention, an electrophotographic photoreceptor is formed by forming a film of the above-mentioned tetrakisazo pigment on a conductive support by vacuum evaporation, or by dispersing it in a suitable binder and forming a film. It can be prepared.

In a preferred embodiment of the present invention, the photoconductive coating described above can be applied as a charge generation layer in an electrophotographic photoreceptor in which the photosensitive layer 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, 5μ or less, in order to shorten the range of the generated charge carriers. Preferably, the thin film layer has a thickness of 0.01 μm to 1 μm. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are recombined and captured! This is due to the need to inject into the charge transport layer without being deactivated by (wrap).

The charge generating layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on the substrate, or can be obtained by forming a vapor deposited film using a vacuum vapor deposition apparatus. The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, including 4, fiJ-N-vinylcarbazole,
It can be selected from organic photoconductive polymers such as polyvinylanthracene and polyvinylpyrene. Preferably, I-rivinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbinate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylpyridine, cellulose-based Examples include insulating resins such as resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. 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 varies depending on the type of resin, and it is preferable to select a solvent that does not dissolve the charge transport layer or the undercoat described below. Specific organic solvents include alcohols such as methanol, ethanol and isopronoenol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetolimide; Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene)・Logonized hydrocarbons or benzene, toluene, xylene, ligroin, monochlorobenzene,
Aromatics such as dichlorobenzene can be used.

Coating methods include dip coating method, spray coating method, spinner coating method, bead coating method,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30°C to 200°C for 5 minutes to 2
It can be carried out stationary or under blown air for a period of time within a range of hours.

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

When a charge transport layer is formed on a charge generation layer, the charge carriers and the substance to be transported in the charge transport layer (hereinafter simply referred to as charge transport substance) are substantially in the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. Preferably, it is insensitive to. The term "electromagnetic waves" used herein includes a broad definition of "light rays" including r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared rays, and the like. When the photosensitive wavelength range of the charge transport layer coincides with or overlaps that of the charge generation layer, charge carriers generated in both layers trap each other, resulting in a decrease in sensitivity.

Charge-transporting substances include electron-transporting substances and hole-transporting substances. Examples of electron-transporting substances include chloranyl, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2.4.7-)linitro=9- Fluorenone, 2.4,5.7-tetranitro-9-fluorenone, 2.4.7-) Rinitro-9-nocyanomethylenefluorenone, 2.4.5.7-titranitroxanthone, 2.4.8-) Examples include electron-withdrawing substances such as linitrothioxanthone and polymerized versions of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N −x ti/l/
Carbazole, N-inpropylcarbazole, N-methyl-N-buenylhydrazino 3-methylitene-9-
Ethylcarbazole, N,N-diphenylhydrazino-
3-methylidene-9-ethylcarbazole, N,N-diphenylhydracino 3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazinol 3-methylidene-10-ditylphenoxazine, P-diethylaminobenzaldehyde N,N-diphenylhydrazone, P-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1.3
．． 3-) rifthylindolenine-ω-aldehyde-N,
Hydrazones such as N-diphenylhydrazone, P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2.5-bix<p-, )xthylaminophenyl)-1,3,4-, txadiazole, 1
-Phenyl-3-(P-diethylaminostyryl)-5
-(P-diethylaminophenyl)pyrazoline, -1-
(quinolyl(2)) -3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl) phenyl)pyrazoline, 1-[6-medoxypyridyl (2)
] -3-(p-diethylaminostyryl)-5-(
P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)virazo I)
7.1-[Pyridyl (2)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)
Pyrazoline, 1-[pyridyl(2))-3-(P-
diethylaminostyryl)-4-methyl-5-(P-diethylaminophenyl)pyrazoline, 1-(pyridyl(
2) ) -3-(α-Methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)hilazoline, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl-5-(P-diethylaminostyryl) phenyl)pyrazoline, 1-phenyl-3-(α-benzyl-P
2-(P-diethylaminostyryl)-6-
Oxazole compounds such as dinithylaminobenzoxazole, 2-(P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2-(P-diethylaminostyryl)-6- Thiazole compounds such as dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamine-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamino-
2-methylphenyl)hebutane, 1. ], ]2.2-tetrakis 4-N,N-dimethylamino-2-methylphenyl) polyarylalkanes such as ethane, triphenylamine, poly-N-vinylcarbasol, polyvinylpyrene, polyvinylanthracene, polyvinylacridine , poly-9-vinylphenylanthracene, pyrene-formal human resin, ethyl carbazole formaldehyde resin W.

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 does not have film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as binders include acrylic resin,
polyester, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, 141J sulfone, polyacrylamide, polyamide, chlorinated rubber, or organic photoconductive resins such as polyJ-N-vinylcarbazole, polyvinylanthracene, and haripinylpyrene. Polymers can be mentioned.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30μ, but the preferred range is 8 to 20μ.
It is. When forming the charge transport layer by coating, suitable coating methods such as those described above can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. As the storage body having a conductive layer, the base itself is conductive, such as aluminum, aluminum alloy, copper, zinc,
Stainless steel, vananium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, innoum-tin oxide alloy, etc. can be used to form 44 films using the vacuum evaporation method. Plastics with formed layers (e.g. polyethylene, polyzolopyrene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (e.g.
(aluminum powder, tin oxide, zinc oxide, titanium oxide, carbon black, silver particles, etc.) together with a suitable binder in plastic or the above-mentioned conductor'1πff1. A substrate coated on a substrate, a substrate made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the subbing layer is 0.1 to 5μ, preferably 0.5 to 3μ.
μ is appropriate.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, the surface of the charge transport layer must be positively charged, and exposure after charging is required. Then, in the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the positive charge, causing a decrease in surface potential and creating an electrostatic contrast with the unexposed area. . A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, developing method, and fixing method may be any known one or any known method, and are not limited to a specific one.On the other hand, the charge transport material may be a hole transport material. In this case, it is necessary to charge the surface of the charge transport layer negatively, and when it is exposed to light after being charged, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the negative charge. , the surface potential attenuates and an electrostatic contrast occurs between the exposed area and the unexposed area.

During development, it is necessary to use a positively charged toner, contrary to the case where an electron transporting substance is used.

When using a photoreceptor in which a conductive layer, a charge transport layer, and a charge generation layer are laminated in this order, if the charge transport material is made of an electron transport material, the surface of the charge generation layer must be negatively charged, and exposure after charging is required. Then, in the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer and then reach the substrate. On the other hand, holes generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a positively charged toner.

This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed. Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or methods, and are not limited to specific ones.

On the other hand, when the charge generation layer is made of a hole transporting substance, the surface of the charge generation layer must be positively charged, and when exposed to light after charging, the holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. and then reaches the base. On the other hand, electrons generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area. During development, it is necessary to use a negatively charged toner, contrary to the case where an electron transporting substance is used.

Further, in another embodiment of the present invention IJ, organic light such as the above-mentioned hydrazones, pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamine, poly-N-vinylcarbazoles, etc. A photosensitive film containing the aforementioned tetrakisazo pigment as a sensitizer for a conductive substance or an inorganic photoconductive substance such as zinc oxide, cadmium sulfide, or selenium can be used. This photosensitive film is formed by coating these photoconductive substances and the above-mentioned tetrakisazo pigment together with a binder.

Another specific example of the present invention is an electrophotographic photoreceptor containing the aforementioned tetrakisazo pigment and a charge transporting substance in the same layer. In this case, in addition to the above-mentioned charge transport substance, a lumi-transfer complex compound consisting of poly(7-N-vinylcarbazole) and trinitrofluorenone can be used. The electrophotographic photoreceptor of this example can be prepared by dispersing the aforementioned tetrakisazo pigment and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a film thereon.

The pigment used in any of the photoreceptors contains at least one pigment selected from tetrakisazo pigments represented by the general formula (1), and its crystal form may be amorphous or crystalline. Good too.

In addition, if necessary, the tetrakisazo pigment represented by the general formula (1) may be used in combination to increase the sensitivity of the photoreceptor or to obtain a highly chromatic photoreceptor. Combining more than one type or known dyes,
It is also possible to use them in combination with charge-generating substances selected from pigments.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers, L
It can also be widely used in electrophotographic applications such as ED printers, liquid crystal printers, and laser engraving.

Hereinafter, the present invention will be explained by examples.

Reference Example: Synthesis of Tetrakisazo Pigment Shop 1 500 - Put 80 water, 33.2 m (0.38 mol) of concentrated hydrochloric acid into a beaker, and while cooling in an ice water bath, prepare an amine with the following structure (the amine is prepared by the method described in French Patent No. 1398240). Synthesized by fc
) 17.91 g (0,029%) was added thereto and stirred while cooling in an ice water bath to bring the liquid temperature to 3°C. Next, a solution of 8.2 F (0,122 mol) of sodium nitrite dissolved in water was heated for 10 minutes while controlling the liquid temperature within the range of 3 to 10 degrees Celsius.
The mixture was added dropwise over a period of minutes, and after the addition was completed, the mixture was stirred for an additional 30 minutes at the same temperature. Add carbon to the reaction solution and filter to obtain a tetrazotized solution.

Next, 2! Put dimethylformamide 700- in a beaker and triethylamine 53.6.9 (0.55 mol)
Add 3-hydroxy-2-naphthoic acid anilide 32.
12 g (0,122 mol) were added and dissolved.

This coupler solution was cooled to 6°C, and while controlling the liquid temperature at 6 to 10°C, the above-mentioned tetrazotized solution was added dropwise over 30 minutes with stirring.Then, the solution was stirred at room temperature for 2 hours and further left overnight. The reaction solution was filtered, washed with water, and filtered to obtain water yeast with a crude pigment content of 43.3.9 in terms of solid content.

Next, filtration with stirring was repeated four times at room temperature using 400-N,N-dimethylformamide. Thereafter, the mixture was repeatedly stirred and filtered twice with 400-g of methyl ethyl ketone, and then dried under reduced pressure at room temperature to obtain a purified pigment of 40.8. I got P. The yield was 82%. Melting point〉250゜Elemental analysis Calculated value (%) Actual value (4) C72.8
572,92 H4,114,07 N 11.44 11.50C14,1
44,04 The synthesis method of typical pigments has been described above, and the general formula (
Other tetrakisazo pigments shown in 1) are also synthesized in the same manner.

Actual examples 1 to 60 An ammonia aqueous solution of casein (casein 1
1.2 1 g of ammonia water, 222 m of water) was applied using a Mayer Parr so that the film thickness after drying would be 10 μm, and then dried.

Next, 1.5 g of the above-exemplified tetrakisazo pigment A was added to a solution prepared by dissolving 2.9 g of butyral resin (degree of butyralization: 63 mol %) in 95 g of ethanol, and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed casein layer using a Mayer Par so that the film thickness after drying would be 0.5 μm, and dried to form a charge generation layer. Next, hydrazone compound 5I of the structural formula and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were mixed with 70 g of benzene.
- and apply it on the charge generation layer so that the film thickness after drying is 1
The photoreceptor of Example 1 was prepared by coating with a Mayer par to a thickness of 2μ and drying to form a charge transport layer. Photoreceptors corresponding to Examples 2 to 60 were prepared in exactly the same manner using other tetrakisazo pigments shown in Table 1 by chemically modifying the tetrakisazo pigment A1.

The electrophotographic photoreceptor produced in this way was sold at Whistle@Co., Ltd.
Using an electrostatic copying paper tester Model 5P-428, corona charging was carried out statically at 15 kV and 1
After being held for 2 seconds, it was exposed to light at an illumination intensity of 21 ux and the charging characteristics were investigated.Next, as for the charging characteristics, the surface potential (Vo) and the amount of exposure necessary to attenuate the potential when dark decaying for 1 second (Ey2) were measured. . The results are shown in Table 1.

Table 1 Table 1 (Continued) Table 1 (Continued) Examples 61 to 65 Fluctuations in bright area potential and dark area potential during repeated use of the photoreceptors used in Examples 1.7, 51, 62, and 97 was measured.

The photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a -5.6 kV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as a cylinder is driven. Using this copying machine, the initial light potential (vL) and dark potential (VD) were set to around -100V and -600V, respectively.
The bright area potential (VL) and dark area potential (VD) were measured after each use. The results are shown in Table 2.

From the data of Examples 1 to 65 in Table 2, the g-photon of the present invention had extremely good electrophotographic sensitivity and excellent VD and vL stability even after repeated use.

Example 66 On the charge generation layer prepared in Example 1, 5 g of 2,4,7-dolinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2'-pronocarbonate (molecular weight 300 ,000) 5 evenings with tetrahydrofuran 7
The coating amount after drying of the coating solution prepared by dissolving in 0- is 10
It was coated to a thickness of 1//m2 and dried.

The electrostatic charge of the electrophotographic photoreceptor thus prepared was measured in the same manner as in Example 1. At this time, the charging polarity was set to ■.

The results were: vo: ■570 delt E’4: 5.01ux, sec.

Example 67 A test film of polyvinyl alcohol 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 tetrakisazo pigment used in Example 1 was applied onto the previously formed polyvinyl alcohol layer using a Mayer bar so that the film thickness after drying was 0.5μ, dried, and charged. A generation layer is formed.

Next, pyrazoline compound 5I of the structural formula and polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid)
A solution obtained by dissolving 5 g of the solution in 70 g of tetrahydrofuran is applied onto the charge generation layer so that the film thickness after drying is 10 μm, and dried to form a charge transport layer.

The charging characteristics and durability characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1 and Sister Example 61.

The results are shown in Table 3.

Table 3 From the results shown in Table 3, the photoreceptor has good sensitivity and good potential stability during long-term use.

Example 68 An ammonia aqueous solution of casein was coated on an aluminum plate with a thickness of 100 microns and dried to form a subbing layer with a thickness of 0.5 microns.

Then, 2.4.7-) Rinitro 9-fluorenone 5
g and poIJ-N-vinylcarbazole (number average molecule i
2300. ooo) was dissolved in 70 portions of tetrahydrofuran to form a charge transfer complex. This charge transfer complex compound and the above-mentioned tetrakisazo pigment 1011 F were added to a solution in which polyester resin (Pylon: manufactured by Toyobo) 5I was dissolved in tetrahydrofuran 7 and Ome, and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 12 microns, and dried. The charging characteristics and durability characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1. . However, the charging polarity was set to ■.

The results were: vo:■575v E'/l: 5゜Olux, sec.

Example 69 The charge transport layer and charge generation layer of Example 1 were sequentially laminated on the casein enriched soil of the AlSi substrate with the casein layer used in Example 1, and the structure was completely the same as that of sister Example 1 except that the layer structure was different. A photoreceptor was formed in the same manner, and the charge was measured in the same manner as in Example 1. However, the band'@polarity was set to ■.

The results were: vo:■565v E’A: 5.0/, ux, sec.

Example 70 Aqueous solution of casein in ammonia (casein 11.2.9.28% aqueous ammonia II,
22.2 m/m of water was applied by dip coating and dried to form a subbing layer with a coating amount of 1,0,9/m2.

Next, the aforementioned Tetrakisazo Pigment Shop 621 Heavy Electrical Department, 1 part by weight of butyral resin (S-LEC BM-2, manufactured by Tsukusui Kagaku Co., Ltd.) and 30 parts by weight of inpropyl alcohol were dispersed for 4 hours using a Goal Mill disperser. .

This dispersion was applied onto the previously formed subbing layer by a dip coating method and dried to form a charge generating layer. The film thickness at this time was 0.3 microns.

Next, 1 part by weight of the hydrazone compound used in Example 1, 1 part by weight of polysulfone resin (P1700: Union Carbide Co., Ltd. 111), and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer. This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time was 12 microns.

A corona discharge of 15 kV was applied to the photoreceptor thus prepared. The surface potential at this time was measured (initial potential Vo).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (dark decay vK). Sensitivity was evaluated by measuring the amount of exposure (E112 microsol/cIF72) required to attenuate the potential vK after dark decay. At this time, gallium/aluminum/
Arsenic ternary semiconductor laser (Dekani 5 rnW,
The oscillation wavelength was 778 nm).

These results were as follows.

Vonny 520yf ■K: 93qb Ek: 2.0-r microjoule/cIrL2 Next, the above was applied to a laser beam printer (LBP-CX manufactured by Canon), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser. The photoreceptor was replaced with an LBP-CX photoreceptor, and an actual image forming test was conducted. The conditions are as follows.

Surface potential after primary band enrichment knee 700V, surface potential after image exposure: -150V (exposure amount 3 μJ/crri'),
Transfer potential: +700V, developer polarity: negative polarity, process speed: 50ml sec, development conditions (development bias) knee 450V, image exposure scan method: image scan, - exposure before next charging: 501 ux-sec red full exposure O image Formation was carried out by line scanning a laser beam in accordance with character signals and image signals, and good prints were obtained for both character and image signals.

〔Effect of the invention〕

According to the present invention, by incorporating a specific tetrakisazo pigment into the photosensitive layer, carrier generation efficiency and/or carrier transport efficiency within the photosensitive layer are significantly improved, and as a result, sensitivity and long-term use are improved. An electrophotographic photoreceptor with excellent potential stability can be obtained.

Claims (5)

[Claims] (1) In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the photosensitive layer has the following general formula (1), ▲ mathematical formula, chemical formula, table, etc. ▼ (1) (in the formula, A is phenol). a coupler residue having a functional OH group;
Ar_1 is an arylene group or a divalent fused polycyclic aromatic ring group which may have a substituent; Ar_2, Ar_3, Ar_4 and Ar_5 are an arylene group or a divalent fused aromatic ring group which may each have a substituent; 1. An electrophotographic photoreceptor comprising a tetrakisazo pigment represented by (representing a divalent heterocyclic group). (2) A in the above general formula (1) is the following general formula (2)
The electrophotographic photoreceptor according to claim 1, which is represented by ~ (8): ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (3) ▲ Mathematical formulas, There are chemical formulas, tables, etc. ▼ (4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (6) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (7) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (8) (In the formula, X is a residue that is fused with a benzene ring to form a polycyclic aromatic ring or a heterocycle; R_3 and R_4 are alkyl, aralkyl, aralkyl, which may each have a substituent;
Represents aryl; Y is a divalent group of an aromatic hydrocarbon or a residue that forms a divalent heterocyclic group together with a nitrogen atom; R_5 and R_6 each have a hydrogen atom and a substituent; optional alkyl, aralkyl, aryl, heterocyclic group, or residues that together form a 5- to 6-membered ring with bonded carbon atoms; R_7 and R_8 are each a hydrogen atom, alkyl, aralkyl that may have a substituent , aryl or heterocyclic group). (3) Claim 1, wherein the photosensitive layer is of a functionally separated type consisting of a charge generation layer and a charge transport layer, and the charge generation layer contains a tetrakisazo pigment represented by the general formula (1). electrophotographic photoreceptor. (4) In the above general formula (2), R_1 is a hydrogen atom, and R_2 is the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_9 is from halogen, nitro, cyano, trifluoromethyl, and acyl. The electrophotographic photoreceptor according to claim 2, which is a substituted phenyl represented by (indicating a selected substituent). (5) In the above general formula (2), R_1 is a hydrogen atom, R_2 is a phenyl group which may have a substituent, and
The electrophotographic photoreceptor according to claim 2, wherein together with a benzene ring, the following group ▲ has the following mathematical formula, chemical formula, table, etc. ▼.