JPS61251862A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form an electrophotographic sensitive body practicably superior in sensitivity and durability by incorporating a specified trisazo pigment in a photosensitive layer. CONSTITUTION:The photosensitive layer contains the trisazo pigment represented by formula (1) in which Ar1-Ar3 are each an optionally substd. arylene or divalent heterocyclic group, and A is a coupler residue having a phenolic OH group. This pigment is typified by table 1, thus permitting one or both of carrier generating efficiency and carrier transfer efficiency to be improved, sensitivity to be enhanced, potential stability to be ensured during use for a long period, and consequently, a stable beautiful image to be obtained independent of its use history.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor in which a photosensitive layer contains a specific azo pigment.

[Prior art]

Electrophotographic photoreceptors using inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components have been known.

Since the discovery that certain organic compounds exhibit photoconductivity, many organic photoconductors have been developed. For example, organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, carbazole,
Low-molecular organic photoconductors such as anthracene, pyrazolines, oxadiazoles, hydrazones, polyarylalkanes, phthalocyanine pigments, azo pigments, cyanine dyes, polycyclic quinone pigments, perylene pigments, indigo dyes, thioindigo dyes Alternatively, organic pigments and dyes such as methine squaric acid dyes are known. Especially organic pigments and dyes that have photoconductivity.

Many photoconductive organic pigments and dyes have been proposed because they are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in the appropriate wavelength range has expanded. For example, U.S. Patent No. 412327
No. 0, No. 4247614, No. 4251613,
Same No. 4251614, Same No. 4256821, Same No. 4
No. 260672, No. 4268596.

As disclosed in 4278747 and 4293628, a disazo pigment exhibiting photoconductivity is used as a charge generation substance in a photosensitive layer that is functionally separated into a charge generation layer and a charge transport layer. What is known?

An electrophotographic photoreceptor using such an organic photoconductor can be produced by a coating method by selecting an appropriate binder, so it is possible to provide an extremely productive and inexpensive photoreceptor. Although it has the advantage of being able to freely control the sensitive wavelength range through selection, this photoreceptor has poor sensitivity and durability, and so far only a few have been put into practical use.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a novel electrophotographic photoreceptor.

Another object of the present invention is to provide an electrophotographic photoreceptor with excellent sensitivity and durability.

[Means for solving problems]

According to the present invention, the following general formula (1)% formula% (wherein Ar11 Ar2 and Ar5 are each an arylene group or a divalent heterocyclic group which may have a substituent, and A has a phenolic OH group) Provided is an electrophotographic photoreceptor characterized in that a photosensitive layer contains a trisazo pigment represented by (a coupler residue).

In the general formula (1), Ar1 e Ar21 Ar
As the definition of 3, examples of the arylene group include phenylene, biphenylene, naphthylene, and anthrylene. Examples of substituents that may be substituted with these include hydroxy group, halogen (chloro).

Bromo, iodo), alkyl (methyl, ethyl, globyl, butyl), alkoxy (methoxy, ethoxy, propoxy, butoxy).

Aryloxy group (phenyloxy), [substituted amino (tumethylamino, diethylamino, dibenzylamino, pyrrolidino, piperidino, morpholino, etc.), nitro, cyano, acyl (acetyl).

Examples include benzoyl, etc.).

Furthermore, as a definition of Ar11 Ar2 * Ars, examples of the heterocyclic group include benzoxazole and benzothiazole.

It is a divalent group such as pyrison, quinoline, thiophene, carbazole, etc., and these may be substituted with the above-mentioned substituents.

At least one of Ar1 + Ar2 and Ars is preferably an arylene group selected from biphenylene, naphthylene, and anthrylene which may have a substituent.

Further, as the coupler residue having a phenolic OH group of A in general formula (1), for example, the following general formula (
2) to (8): , Y, (wherein X is a residue condensed with a benzene ring to form a polycyclic aromatic ring or a bicyclic ring; R3 and R4 are hydrogen.

Alkyl, aralkyl, aryl or heterocyclic group which may have a substituent or together form a cyclic amino group with a nitrogen atom; R5 and R6 each have an optional substituent and alkyl, aralkyl, aryl Y represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group together with a nitrogen atom; R7 represents an aryl or heterocyclic group which may have a substituent. ;R8
and R2 are alkyl and aralkyl, each of which may have a substituent. aryl or heterocyclic group).

The polycyclic aromatic ring of X is, for example, naphthalene.

Examples include anthracene, carbazole, benzcarbasol, dibenzofuran, benzonaphthofuran, and diphenylene sulfide. These may be substituted with the substituents described above.

Also R3. In the case of R4, alkyl is, for example, methyl.

Ethyl, propyl, butyl, etc. are shown, aralkyl is, for example, benzyl, phenethyl, naphthylmethyl, etc., and aryl is, for example, phenyl, diphenyl, naphthyl, anthryl, etc. Especially when R3 is hydrogen, R4
A compound having a structure in which the phenyl group is a phenyl group having an electron-withdrawing group such as halogen, nitro, cyan, or trifluoromethyl at the ○-position is preferable. These may have substituents.

The heterocycle is carbazole 8 dibenzofuran.

benzimidacilone, benzthiazole, thiazole,
Examples include pyridine.

Specific examples of R5 and R6 are the same as those exemplified above for R, and R4. These may be substituted with the substituents described above.

In the definition of Y, the divalent aromatic hydrocarbon group includes, for example, a monocyclic aromatic hydrocarbon group such as O-7 enylene, 0-
Su7tyrene, perinaphthylene.

Examples include fused polycyclic aromatic hydrocarbon groups such as 1,2-antrylene and 9,10-phenanthrylene.

Further, as examples of forming a divalent heterocycle together with a nitrogen atom, 3.4-pyrazolediyl group, 2.3-pyridinenoyl group, 4.5-pyrimidinediyl group, 6.7-
Examples include 5- to 6-membered heterocyclic divalent groups such as 4-ntazolediyl group, 5.6-benzimidazolediyl group, and 6.7-chiralindiyl group.

The aryl group or heterocyclic group for R7 is phenyl.

Naphthyl, anthryl, pyrenyl, etc.; pyridyl.

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

Specific examples of alkyl, aryl, and aralkyl in R8 and R are the same as those listed above. Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine. These may be substituted with the substituents described above.

Although the present invention is not bound by theory, since the conjugation between the azo groups of the pigment molecules forming the skeleton of the azo pigment of general formula (1) is considered, the charge generated by light can move freely. is thought to have bt-, which improves charge transfer between molecules. Therefore, by incorporating the azo pigment of general formula (1) into the photosensitive layer, either or both of carrier generation efficiency and carrier transport efficiency will be improved, improving sensitivity and ensuring potential stability during long-term use. It turns out.

Furthermore, since it achieves high sensitivity, it can be applied to radar beam printers, IJD printers, liquid crystal printers, etc. Also, stable potential is ensured regardless of the previous history of the photoreceptor, so stable and beautiful images can be obtained. .

Representative examples of azo pigments used in the present invention are listed in Table 1.

These disazo pigments can be used alone or in combination of two or more.

In addition, these pigments can be used, for example, with the general formula % (where Ar1+ Ar2 and Ars in the formula are represented by the general formula (1
)) is hexazotized by a conventional method, and then the corresponding coupler is coupled in an aqueous system in the presence of an alkali, or the hexazonium salt of the above triamine is converted into a borofluoride salt or a borofluoride salt. It can be easily produced by once isolating it in the form of zinc chloride double salt, etc., and then coupling it with a coupler in the presence of an alkali in a suitable solvent such as N,N-trimethylformamide, dimethyl sulfoxide, etc. I can do it.

Next, a typical synthesis example of the trisazo pigment used in the present invention is shown below.

Synthesis example (synthesis of the exemplified trisazo pigment 'A1) 500
d In a beaker, water 120-1 concentrated hydrochloric acid 24.9wt (0,2
9 mol), 9.98 (0,029 mol) of a compound of the following formula.The mixture was stirred while being cooled in an ice-water bath to bring the liquid temperature to t-3°C.

Next, a solution of sodium nitrite 6.4.9 (0,093 mol) 1 dissolved in water lid was added dropwise over 10 minutes while controlling the liquid temperature within the range of t-3 to 10°C. After the dropping was completed, the temperature remained the same. The mixture was further stirred for 30 minutes. Carbon was added to the reaction solution and filtered. Sodium borofluoride hydrochloride 38°2.9 (0.3
A precipitate obtained by adding a solution dissolved in 65 wt of T-water (5 mol) was added, and the precipitate was separated from F, washed with water, filtered, and thoroughly pressed on a P filter to obtain hexazonium trifluorofiltrate in a wet state.

Next, 1800 di of DMF was placed in a 2Il beaker, and 24.5.9 (0,093 mol) of 3-hydroxy-2-naphthoic acid anilide as a coupling component and the above-mentioned hexazonium salt were dissolved, and the liquid temperature was cooled to 7°C. into this solution while stirring) IJ ethylamine 61.7.
9 (0.61 mol) was added dropwise over 30 minutes while maintaining the liquid temperature at 5 to 10°C. After completion of the dropwise addition, the mixture was stirred for another 2 hours, left at room temperature overnight, and then filtered. The obtained pigment was stirred with water 11, washed, and filtered three times each, and then DMF
Stirring, washing, and filtration were repeated four times using MEK 600- and twice using MEK 600-, respectively.

The resulting paste was dried with air at room temperature to give 28.7g (
A pigment with a yield of 85% was obtained.

Melting point 250°C or higher Elemental analysis Calculated value C Actual value Pot C75,2475,01 H4,334,13 N 10.82 10.73 Other trisazo pigments represented by the above general formula (1) can also be prepared in the same manner as in the above synthesis example. It can be synthesized on a regular basis.

In a preferred embodiment of the present invention, a trisazo pigment represented by the general formula (1) can be used as a charge generation substance in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. the charge generating layer contains as much of the trisazo pigment as possible to obtain sufficient absorbance;
In order to prevent the generated charge carriers from being trapped in the charge generation layer, it is preferable to use a thin film layer, for example, a thin film layer having a thickness of 5 microns or less, preferably L<0.01 micron to 1 micron. . This means that most of the incident light is absorbed by the charge generation layer, generating a large number of charge carriers, and that the generated charge carriers are not deactivated by recombination or capture (trough f) in the charge transport layer. This is due to the need to inject.

The charge generation layer can be formed by dispersing the above-mentioned trisazo pigment in a suitable binder and coating it on a substrate, or can be obtained by forming a deposited film using a vacuum deposition apparatus. The binder that can be used when forming the charge generating layer by coating can be selected from a wide variety 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 (bisphenol A, Z tie f, etc.) de lyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin , polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, I-rivinylpyrrolidone nanoinsulating resin. The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

Solvents that dissolve these resins vary depending on the type of resin, and are preferably selected from those that do not dissolve the underlying charge transport layer or subbing layer. Specific organic solvents include alcohols such as methanol, ethanol, and isopro-4-nol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide,
Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydro7rane, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and fats such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Group halogenated hydrocarbons, aromatics such as toluene, xylene, refloin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating method, spray coach ink method, spinner coach ink method, heat coating method,
This can be carried out using a coating method such as a Mayer bar coating method, a grade coating method, a roller coach ink 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 a draft for a time range of hours.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving and taking 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, this charge transport layer may be laminated on or under the charge generation layer.

When the charge transport layer is formed on the charge generation layer, the material that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport material) is substantially in the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. Preferably, it is insensitive to. The reason is that the charge transport layer has a filter effect and prevents a decrease in sensitivity. The "electromagnetic waves" mentioned here include r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays,
Includes a broad definition of "ray" that includes far-infrared rays.

The charge transporting substances include electron transporting substances and hole transporting substances, and the electron transporting substances include chloranil, chromoanil, tetracyanoethylene, tetracyanoquinodimethane, 9nitro-9-fluorenone, 2,4,5.7-tetranitro-9-fluorenone, 2,4,7-)linitro-9-socyanomethylenefluorenone, 2,4,5.7-titranitroxanthone, 2,4.8-trinitrothioxa There are electron-withdrawing substances such as 7 tons, and polymerization of these electron-withdrawing substances.

Examples of hole transporting substances include 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-ethylphenothiazine, N, N-diphenylhydrazino-3-methylisono-10-ethylphenoxazine, P-diethylaminobenzaldehyde-N,N-diphenylhydrazone, P-
Noethylaminobenzaldehyde N-α-suphthyl-N-phenylhydrazone, p-v lolidinobenzaldehyde N, N-diphenylhydrazo:y, 1e3a3-
)' li/tylindolenine-ω-aldehyde-N,
Hydrazones such as N-diphenylhydrazone, P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1- Phenyl-3-(P-diethylaminostyryl)-s-(
p-diethylaminophenyl)pyrazoline, 1-(quinolyl(2))-3-(P-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline,
1-[pyridyl(2))-3-(P-diethylaminostyryl)-s-(p-diethylaminophenyl)pyrazoline, 1-(6-medoxybilidyl(2))-
3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3
) E -s -(p-diethylaminostyryl)-s
-(p-diethylaminophenyl)pyrazoline, 1-[
Pyridyl(2)) -3-(P-dimethylaminostyryl/I/) -5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(2))-3-(P-diethylaminostyryl)-4- Methyl-5-(P-zoethylaminopheny/L/)pyrazoline, i-(pyridyl(
2) ) -3-(α-Methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, l-7: Vinyl-3-(P-diethylaminostyryl)-4-methy/L/-5 birazolines such as -(P-diethylaminophenyl)pyrazoline, 2-( P-diethylaminostyryl)-6-ethylaminobenzoxazole, 2-(
Oxazole compounds such as P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-ac1 phenyl)oxazole, 2-(P-diethylaminostyryl)-6-dinitylaminopene! Thiazole compounds such as thiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamino-2-methylphenyl)butane ,1,1,
2.2-tetrakis(4-N,N-dimethylamine-2
- I-aryl alkanes such as methylphenyl)ethane, triphenylamine, stilbene derivatives, aromatic polycyclic compounds having a styryl group, heterocyclic compounds, poly-H
-vinylcarbazole, I-rivinylpyrene, polyvinylanthracene, I-ripinylacridine, poly-9-vinylphenylanthracene, 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.

(9) 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 polyarylate, I-lyester, polycarbonate (bisphenol A, Z type, etc.)/restyrene. Acrylonitrile-styrene copolymer, acrylonitrile-
getadiene copolymer, polyvinyl butyral, /l)
Examples include insulating resins such as vinyl formal, polysulfone, polyacrylamide, polyamide, chlorine, and rubber, and organic photoconductive I-rimers such as 4-N-vinylcarbazole, 4-rivinylanthracene, and I-rivinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Typically it is 5 microns to 30 microns, with a preferred range of 8 microns to 20 microns. When forming the charge transport layer by coating, an appropriate coating method as 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. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and in addition, plastics having a layer formed by vacuum evaporation of aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. (for example, A substrate made of glass coated with conductive particles (e.g., carnon black, silver particles, etc.) with a suitable binder, conductive A substrate made of plastic or paper impregnated with 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,
? Rivinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 6101 copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 micron to 5 micron, preferably 0.5 micron to 3 micron.

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., 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, and then visually imaged and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. , which then reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between the surface potential and the unexposed area.

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

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned trisazo pigment and a charge transport material in the same layer. In this case, a charge transfer complex compound consisting of poly-N-vinylcarbashield trinitrofluorenone can be used in addition to the above-mentioned charge transport substance.

The electrophotographic photoreceptor of this example can be prepared by dispersing the aforementioned trisazo pigment and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran and forming a film using a coating solution obtained.

In any of the photoreceptors, the pigment used has the general formula (1)
It contains at least one type of pigment selected from the trisazo pigments shown in the following, and its crystal form may be amorphous or crystalline.

In addition, if necessary, two types of trisazo pigments represented by the general formula (1) may be used in combination to increase the sensitivity of the photoreceptor or to obtain a panchromatic photoreceptor by combining pigments with different light absorptions. It is also possible to use a combination of the above, or a combination with a charge generating substance selected from known dyes and pigments.

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

The present invention will be explained below with reference to Examples.

Examples 1 to 40 Ammonia aqueous solution of casein (casein 1
1.2I! , 28% ammonia water 111 water 222d) was applied using a Mayer bar so that the film thickness after drying was 1.0 microns, and dried.

Next, 5y of the above-mentioned trisazo pigment I61 was added to a solution prepared by dissolving butyral resin (butyralization degree 63 mol) 2II in 95-ethanol, and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed casein layer using a Mayer bar so that the film thickness after drying would be 0.5 microns, and dried to form a charge generation layer.

Next, 5 g of the hydrazone compound of the structural formula and polymethyl methacrylate resin (number average molecular weight 1,100,000) were mixed with benzene 70-
and apply it on the charge generation layer so that the film thickness after drying is 12
A photoreceptor was prepared by coating with one fire per coat to a micron thickness and drying to form a charge transport layer. Photoreceptors of Examples 2 to 40 were prepared in the same manner using the azo pigments shown in Table 1 instead of trisazo pigment A1.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
Using an electrostatic copying paper tester Model 5P-428, the sample was statically charged with a corona at -5 kV, held in a dark place for 1 second, and then exposed to light at an illuminance of 2 lux to measure the charging characteristics.

The charging characteristics include the surface potential (Vo) and the exposure amount EM (lu
x-sea) was measured. The results are shown in Table 2.

Table 2 Table 2 (Continued) Comparative Examples 1 to 5 The pigments of the illustrative trisazo pigments AI, 7.19, and 3o are designated as Comparative Pigments 1 to 4, respectively. Exemplary trisazo pigment &4
Comparative Pigment 5 is a suazo pigment having a central skeleton of No. 8. A photoreceptor was prepared in exactly the same manner as in Example 1 using Comparative Pigments 1 to 5 in place of the pigment of Example 1, and charge measurement was performed.

Table 3 shows the characteristics of comparative examples compared to the present invention.

As is clear from the results in Table 3, it has been confirmed that the electrophotographic sensitivity of the photoreceptor of the present invention is significantly improved by introducing an arylene group with π-electron expansion, such as naphthylene or biphenylene, into the central skeleton of the pigment. It was done.

Examples 41 to 45 and Comparative Examples 6 to 10 Bright area potential and dark area potential during repeated use using the photoreceptors used in Examples 1, 7, 16, 24.33 and the photoreceptors used in Comparative Examples 1 to 5 The fluctuation of was measured. The method is -5,6k
V corona charger, exposure optical system, developer, transfer charger,
The photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a static elimination exposure optical system and a cleaner. This copier is
The structure is such that an image is obtained on the transfer paper as the cylinder is driven. Using this copying machine, the initial bright area potential (
vL) and dark potential (VD) at -100V and -100V, respectively.
The bright area potential (vL) and dark area potential (VD) were measured after being set at around 600 V and used 5000 times. The results are shown in Table 4.

The photoreceptor of the present invention had extremely good VD and vL stability even during repeated use.

Example 46 On the charge generation layer prepared in Example 1, 2,4,7-dolinitro-9-fluorenone 5I and poly-4,4'-dioxydiphenyl-2,2'-fronocargenate (molecular weight 300,000) 5 & in tetrahydro 7 run 70-, the coating amount after drying is 1.
011/m 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 e. The results are shown in Table 5.

Table 5 Vo: e580 & LutoEy, : 6.31ux, a*e Example 47 A 4-livinyl alcohol film with a thickness of 0.5 microns was formed on the aluminum surface of an aluminum in/liethylene tele-7 tallate film. .

Next, the dispersion of the trisazo pigment used in Example 1 was applied onto the previously formed polyvinyl alcohol layer using a Mayer perr so that the film thickness after drying would be 0.5 microns, dried and charged. A generation layer was formed.

Next, a solution prepared by dissolving the stilbene derivative 2.5II of the structural formula, the pyrazoline compound 2.51 of the structural formula, and the polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid) 5I in 70 g of tetrahydrofuran was added to the charge generation layer. It was coated on top so that the film thickness after drying was 10 microns, 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 Examples 1 and 41.

The results are shown in Table 6.

Table 6 Vo: e600V ElAa 4.91ux, s@e Durability characteristics initial After 5000 sheets durability vDvLvDv
L -600V-100V, -620V -120 From the results in Table 6, the photoreceptor of the present invention has good sensitivity and good potential stability during long-term use.

Examples 43 to 48 An aqueous casein solution was applied onto an aluminum plate having a thickness of 100 microns and dried to form a subbing layer having a thickness of 0.5 microns.

Next, 2,4.7-)lini)o-9-fluorenone 5
g and poly-N-vinylcarbazole (number average molecular weight 30
0,000) was dissolved in 70-g of tetrahydrofuran to form a charge transfer complex. This charge transfer complex compound and the above-mentioned trisazo pigment (26) 1 , f
e. 5 g of polyester resin (manufactured by Byron Toyobo) was added to a solution dissolved in 70 m of tetrahydrofuran 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 photoreceptors thus prepared were measured in the same manner as in Examples 1 and 41. The results are shown in Table 7. However, the charging polarity was set to e.

Table 7 vo: (9590V J: 5.6 1ux, a@c Endurance characteristics initial time After 5000 sheets durability vDvLvDvL +600 +110 +615 +125
Example 49 Same as Example 1 except that the charge transport layer and charge generation layer of Example 1 were sequentially laminated on the casein layer of the aluminum substrate provided with the casein layer used in Example 1, and the order of the layer structure was different. A photoreceptor was prepared in exactly the same manner as in Example 1, and a band was formed! I took measurements. However, the charging polarity was set to 't(E). The band t% properties are shown in Table 8.

Table 8 Vo: ■590V

Claims (5)

[Claims] (1) The following general formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (1) (In the formula, Ar_1, Ar_2, and Ar_3 are each an arylene group or a divalent heterocyclic group that may have a substituent. and A is a coupler residue having a phenolic OH group. (2) The electrophotographic photoreceptor according to claim 1, wherein Ar_1, Ar_2, and Ar_3 in the general formula (1) are arylene groups selected from biphenylene, naphthylene, and anthrylene, each of which may have a substituent. (3) A in the above general formula (1) is the following general formula (2)
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, 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) ▲ Mathematical formulas , chemical formulas, tables, etc. ▼ (8) (In the formula, , aralkyl, aryl, or a heterocyclic group, or together with a nitrogen atom, form a cyclic amino group; R_5 and R_6 each represent an alkyl, aralkyl, or aryl that may have a substituent;
Y is an aromatic hydrocarbon divalent group or forms a heterocyclic divalent group together with a nitrogen atom; R_7 represents an aryl or heterocyclic group which may have a substituent; R_
8 and R_9 each represent an optionally substituted alkyl, aralkyl, aryl or heterocyclic group). (4) The electron of claim 1, wherein the photosensitive layer is a functionally separated type consisting of a charge generation layer and a charge transport layer, and the charge generation layer contains an azo pigment represented by the general formula (1). Photographic photoreceptor. (5) R_3 in the above general formula (2) is hydrogen,
The electrophotographic photoreceptor according to claim 3, wherein R_4 is a substituted phenyl represented by the following general formula (wherein R_1_0 is a substituent selected from halogen, nitro, cyano, and trifluoromethyl).