JPS6135549B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing a bisazo compound. More specifically, the present invention relates to a highly durable electrophotographic photoreceptor that has high sensitivity and is suitable for repeated use. Conventionally, electrophotographic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductor such as selenium, zinc oxide, or cadmium sulfide have been widely used. However, these are not necessarily fully satisfactory in terms of sensitivity, heat resistance, moisture resistance, printing durability, etc. In addition, selenium and cadmium sulfide in particular have limitations in production and handling due to their toxicity. On the other hand, electrophotographic photoreceptors having a photosensitive layer mainly composed of an organic photoconductive compound are relatively easy to manufacture, have low manufacturing costs, and can be shaped into either a cylindrical drum shape or a sheet shape. It has many advantages in recent years, such as being easy to handle and having excellent heat resistance, whereas selenium photoreceptors generally have poor heat resistance and crystallize under high temperature conditions. There is. As such an organic photoconductive compound, poly-
N-vinylcarbazole is known, and electrophotographic photoreceptors having a photosensitive layer mainly composed of a charge transfer complex formed from N-vinylcarbazole and a Lewis acid such as 2,4,7-trinitro-9-fluorenone have already been developed. It has been put into practical use. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and printing durability. On the other hand, functionally separated electrophotographic photoreceptors, such as laminated or dispersed types, are known in which the carrier generation function and the carrier transport function of the photoconductive function are assigned to separate substances, respectively. Such functionally separated electrophotographic photoreceptors have a wide range of materials to choose from, making it relatively easy to achieve high performance in electrophotographic properties such as charging characteristics, sensitivity, residual potential, and printing durability. It has the advantage that it is easy to create an electrophotographic photoreceptor having the following characteristics. Various carrier-generating substances have been proposed in the past as carrier-generating substances that primarily perform carrier generation among the photoconductive functions of electrophotographic photoreceptors. For example, a carrier generation layer formed from amorphous selenium as an inorganic material is well known, but this has the disadvantage that it crystallizes under high temperature conditions and its performance deteriorates.
In addition, various proposals have been made to use photoconductive organic dyes and pigments that have particularly excellent carrier-generating ability as carrier-generating substances.
48-30513 or JP-A-53-95033, JP-A-54-12742, JP-A-56-116040
Azo compounds such as those described in US Pat. No. 4,052,210 are already known. However, these azo compounds do not necessarily satisfy the characteristics such as sensitivity, residual potential, or stability when used repeatedly, and the selection range of carrier transport materials is also limited, which makes them difficult to meet the wide demands of electrophotographic processes. The reality is that nothing that fully satisfies these requirements has yet been obtained. The object of the invention is to be stable to heat and light;
Another object of the present invention is to provide an electrophotographic photoreceptor containing a bisazo compound having excellent carrier generation ability. Another object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity, low residual potential, and excellent durability whose characteristics do not change even after repeated use. As a result of intensive research to achieve the above object, the present inventors discovered that a bisazo compound represented by the following general formula [], preferably the general formula [], can act as an active ingredient of a photoreceptor, and the present invention This is the completed version. General formula〓〓〓〓〓〓
In the formula, R ₁ represents a hydrogen atom, a halogen atom, or a cyano group, preferably a hydrogen atom. Rh represents a substituted or unsubstituted phenylene group. As a substituent, for example, a substituent having 1 to 4 carbon atoms,
Unsubstituted alkyl group, substituted/unsubstituted alkoxy group having 1 to 4 carbon atoms, halogen atom, cyano group, cargyxyl group, ester group thereof, carbamoyl group,
Examples include an acyl group, a hydroxy group, an acyloxy group, an aryloxy group, a sulfo group, a sulfamoyl group, a sulfone group, an acylamino group, a sulfonamido group, and preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms; Substitution with 1 to 4 carbon atoms
These are unsubstituted alkoxy groups, halogen atoms, and cyano groups. A is

【formula】

【formula】

[expression] or

[Formula], where Y is a hydrogen atom, a hydroxy group, a carboxy group, an ester group thereof, a sulfo group, a substituted or unsubstituted sulfamoyl group, preferably a substituted or unsubstituted carbamoyl group

[Formula] Replaced/Unused Substituted sulfamoyl group

[Formula], where R ₄ is a hydrogen atom, a substituted compound having 1 to 4 carbon atoms,
Unsubstituted alkyl groups and substituted/unsubstituted phenyl groups, R ₅ is a hydrogen atom, substituted/unsubstituted alkyl groups having 1 to 4 carbon atoms, substituted/unsubstituted aromatic carbocyclic groups (e.g. phenyl group, substituted/unsubstituted naphthyl group, substituted/unsubstituted anthryl group, etc.), or substituted/unsubstituted aromatic heterocyclic group (e.g., substituted/unsubstituted carbazolyl group, substituted/unsubstituted dibenzofuryl group, etc.) (base, etc.). Substituents for these groups include, for example, alkyl groups having 1 to 4 carbon atoms, halogen atoms such as chlorine atoms and bromine atoms, alkyl groups having 1 to 4 carbon atoms, hydroxy groups, and aryloxy groups such as phenoxy groups and naphthoxy groups. group, acyloxy group, carboxy group, ester group thereof,
Examples include a carbamoyl group, an acyl group, a sulfo group, a sulfamoyl group, an amino group, an acylamino group, a sulfonamide group, a cyano group, a nitro group, and preferably a lower alkyl group having 1 to 4 carbon atoms,
Halogen atoms such as chlorine atoms and bromine atoms, carbon number 1
~4 lower alkoxy groups, cyano groups, and nitro groups. Z is substituted/unsubstituted aromatic carbocycle or substituted/unsubstituted aromatic carbocycle
Atom groups necessary to form an unsubstituted aromatic heterocycle, specifically, for example, substituted/unsubstituted benzene rings, substituted/unsubstituted naphthalene rings, substituted/unsubstituted indole rings, substituted/unsubstituted indole rings, etc. Represents a group of atoms forming an unsubstituted carbazole ring, etc. Examples of substituents for the atomic group forming these rings include a series of substituents such as those listed as substituents for R ₄ and R ₅ , but halogen atoms, sulfo groups, and sulfamoyl groups are preferred. R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group,
〓〓〓〓〓
Substituted/unsubstituted amino group, carboxy group, ester group thereof, substituted/unsubstituted carbamoyl group, cyano group, preferably hydrogen atom, carbon number 1-4
are an alkyl group and a cyano group. R ₂ is a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted phenyl group, and examples of substituents for these groups include a series of substituents such as those listed as substituents for R ₄ and R ₅ . Among these groups, preferred are a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. R ₃ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, preferably an alkyl group having 1 to 4 carbon atoms, or a phenyl group. General formula [] In the formula, R ₁ and A are the same as in the general formula []. R ₂ is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms, a halogen atom, a cyano group, a carboxy group, an ester group thereof, a carbamoyl group, an acyl group, Hydroxy group, acyloxy group, aryloxy group,
A group selected from a sulfo group, a sulfamoyl group, a sulfone group, an acylamino group, and a sulfonamide group, preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. , is a cyano group. That is, in the present invention, the advantages of the bisazo compound of the present invention can be improved by using the bisazo compound represented by the general formula [] and the general formula [] as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor. By utilizing only the carrier generation ability of the carrier and using it as a carrier generation material for a function-separated electrophotographic photoreceptor in which carrier generation and transport are performed by separate substances, the film has excellent physical properties, such as charge retention, sensitivity, It is possible to produce an electrophotographic photoreceptor that has excellent electrophotographic properties such as residual potential, shows little deterioration due to stress even after repeated use, and can exhibit robust and stable properties against heat, light, etc. Examples of the bisazo compounds useful in the present invention represented by the general formulas [] and [] include those having the following structural formulas, but the bisazo compounds of the present invention are not limited by this. do not have. 〓〓〓〓〓
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〓〓〓〓〓
〓〓〓〓〓
〓〓〓〓〓
〓〓〓〓〓
〓〓〓〓〓
〓〓〓〓〓
〓〓〓〓〓
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〓〓〓〓〓
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The above bisazo compounds can be easily synthesized by known methods. Synthesis Example 1 (Synthesis of Exemplified Compound (K-3)) Obtained by reacting naphthalene (1, 4, 5, 8) tetracarboxylic dianhydride and p-nitroaniline in N-methylpyrrolidone in the presence of pyridine. Naphthalene (1, 4, 5, 8) tetracarboxylic acid-N,N'-di-(p-nitrophenyl)-diimide was reduced with tin and hydrochloric acid to form naphthalene (1, 4, 5, 8).
5.8) Tetracarboxylic acid -N・N'-di-(p-
Aminophenyl) diimide was obtained. 4.48 g (0.01 mol) of naphthalene (1, 4, 5, 8) tetracarboxylic acid-N, N'-di-(p-aminophenyl) diimide thus obtained was dispersed in a mixture of 20 ml of concentrated hydrochloric acid and 20 ml of water. 1.52g (0.022
An aqueous solution of 5 ml of sodium nitrite dissolved in 5 ml of water was added dropwise while maintaining the internal temperature between 0°C and 5°C.
The mixture was stirred at the same temperature for 1 hour. After the reaction, a small amount of residue was separated by filtration, and 30 ml of 42% aqueous 42% borohydrofluoric acid solution was added to the filtrate, and the precipitate precipitated was collected by filtration, washed with water, and thoroughly dried. Obtained tetrazo〓〓〓〓〓
The tetrazonium salt was dissolved in 50 ml of N.N-dimethylformamide to obtain a tetrazonium salt to be used in the next reaction. Next, 5.27 g (0.02 mol) of 2-hydroxy-3-naphthoic acid anilide (naphthol-AS) and 5.4 g of triethanolamine were dissolved in 400 ml of N/N-diethylformamide, and the internal temperature was kept at 5 to 10°C. At the same time, the tetrazonium salt solution prepared above was added dropwise, stirred at the same temperature for 2 hours, and further stirred and reacted at room temperature for 2 hours. Thereafter, the deposited precipitate was collected by filtration, washed with N.N-dimethylformamide and then with acetone, and dried to obtain 6.2 g of the target bisazo compound. Melting point: 300° C. or higher Imide absorption appeared at ν = 1690 cm ⁻¹ in the infrared absorption spectrum, and a molecular ion +1 peak of m/e 869 appeared in the FD-mass spectrum, confirming that the target substance was synthesized. Synthesis Example 2 (Synthesis of Exemplary Compound (K-7)) 6.16 g (0.02 mol) of 2-hydroxy-3-naphthoic acid-3'-nitroanilide (naphthol AS-BS) was added to 700 ml of N-N-dimethylamide. Dissolve, add 20g of sodium acetate, and lower the internal temperature to 5-10
While maintaining the temperature at °C, 50 ml of a solution of the tetrazonium salt (0.01 mol) prepared in Synthesis Example (1) in N·N-dimethylformamide was gradually added. The mixture was further stirred at the same temperature for 2 hours, and further stirred and reacted at room temperature for 2 hours. The precipitate deposited after the reaction was collected by filtration, washed with N.N-dimethylformamide, then water, then acetone, and dried to obtain 6.8 g of the target bisazo compound. Touch point 300℃ or higher In the infrared absorption spectrum, imide absorption is at ν = 1690 cm ^-1 , and m/e = in the FD-mass spectrum.
Since a peak of molecular ion +1 appeared at 959, it was confirmed that the target substance had been synthesized. Synthesis Example 3 (Synthesis of Exemplified Compound (K-9)) Naphthalene (1, 4, 5, 8) tetracarboxylic dianhydride and 2-chloro-4-nitroaniline in N-methylpyrrolidone in the presence of pyridine. Naphthalene (1, 4, 5, 8) tetracarboxylic acid-N,N'-di-(2-chloro-4) obtained by the reaction.
-Nitrophenyl) diimide is reduced with tin and hydrochloric acid to produce naphthalene (1458) tetracarboxylic acid -N.
N'-di-(2-chloro-4-aminophenyl)diimide was obtained. Naphthalene (1.4.
5.8) Tetracarboxylic acid-N・N'-di-(2-
Chlor-4-aminophenyl) diimide 4.46g
(0.01 mol) was dispersed in a mixture of 15 ml of hydrochloric acid and 15 ml of water, and an aqueous solution of 1.52 g (0.022 mol) of sodium nitrite dissolved in 5 ml of water was added dropwise while maintaining the internal temperature at 0 to 5°C. The mixture was further stirred and reacted at the same temperature for 1 hour. After the reaction, a small amount of residue was filtered off, 30 ml of 42% aqueous borohydrofluoric acid solution was added to the filtrate, and the precipitate was collected by filtration, washed with water, and thoroughly dried. The obtained tetrazonium salt was dissolved in 50 ml of N.N-dimethylformamide.
A tetrazonium salt solution was prepared for use in the next reaction. Next, 2-hydroxy-3-naphthoic acid-2'
4′-dimethylanilide (naphthol AS-MX)
5.83g (0.02mol), triethanolamine 5.4g
was dissolved in 400 ml of N-N-dimethylformamide, and the tetrazonium salt aqueous solution prepared above was added dropwise while maintaining the internal temperature at 5 to 10°C, stirred at the same temperature for 2 hours, and further stirred and reacted at room temperature for 2 hours. Ta. The deposited precipitate was collected by filtration, washed with N.N-dimethylformamide, then acetone, and dried to obtain 6.3 g of the target bisazo compound. Melting point: 300℃ or higher Infrared absorption spectrum shows imide absorption at ν=1690cm ^-1 and m/e=1051 in FD-mass spectrum
Since a peak of molecular ion +1 appeared, it was confirmed that the target substance was synthesized. The bisazo compound of the present invention has excellent photoconductivity, and when an electrophotographic photoreceptor is manufactured using the same, a photosensitive layer in which the bisazo compound of the present invention is dispersed in a binder is formed on a conductive support. It can be manufactured by providing. Another method is to use the bisazo compound of the present invention as a carrier generating substance that utilizes the particularly excellent carrier generating ability of its photoconductivity, and to use it together with a carrier transporting substance that can effectively act in combination with the bisazo compound. Laminated or distributed type so-called function-separated electronic photography
It is also possible to use a euphotoreceptor. Various mechanical configurations of electrophotographic photoreceptors are known, and the electrophotographic photoreceptor of the present invention can take any of these forms. Usually, the configuration is as shown in FIGS. 1 to 6. In FIGS. 1 and 3, a photosensitive layer is formed of a laminate of a carrier generating layer 2 containing the above-mentioned bisazo compound as a main component and a carrier transport 3 containing a carrier transport substance as a main component on a conductive support 1. 4 will be provided. As shown in FIGS. 2 and 4, this photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support. When the photosensitive layer 4 has a two-layer structure in this manner, an electrophotographic photoreceptor having the most excellent electrophotographic properties can be obtained. Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing the carrier generating substance 7 in a layer 6 containing a carrier transporting substance as a main component is formed on the conductive support 1. It may be provided directly or via an intermediate layer 5. When the bisazo compound of the present invention is used as a carrier generating substance, examples of the carrier transporting substance used in combination with the bisazo compound include electron-accepting substances that easily transport electrons such as trinitrofluorenone or tetranitrofluorenone, as well as poly-N-
Polymers or triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives having a heterocyclic compound in the side chain, such as vinyl carbatool. Examples include electron-donating substances that easily transport holes, such as derivatives, triarylamine derivatives, carbazole derivatives, and stilbene derivatives, but the carrier transport substance used in the present invention is not limited to these. The carrier generation layer 2 constituting the photosensitive layer 4 having a two-layer structure is the conductive support 1 or the carrier transport layer 3.
It can be formed directly thereon or with an intermediate layer such as an adhesive layer or barrier layer interposed as required by the following method. M-(1) A method of applying a solution in which a bisazo compound is dissolved in a suitable solvent, or a solution in which a binder is added and mixed as necessary. M-(2) A method in which a bisazo compound is made into fine particles in a dispersion medium using a ball mill, a homomixer, etc., and a binder is added if necessary to mix and disperse the resulting dispersion. Examples of the solvent or dispersant used for forming the carrier generation layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N/N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, Examples include toluene, xylene, chloroform, dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and the like. When using a binder in the carrier generation layer or carrier transport layer, any binder can be used, but it is preferable to use a film-forming polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating. . Examples of such high molecular weight polymers include, but are not limited to, the following. P-(1) Polycarbonate P-(2) Polyester P-(3) Methacrylic resin P-(4) Acrylic resin P-(5) Polyvinyl chloride P-(6) Polyvinylidene chloride P-(7) Polystyrene P- (8) Polyvinyl acetate P-(9) Styrene-butadiene copolymer P-(10) Vinylidene chloride-acrylonitrile copolymer P-(11) Vinyl chloride-vinyl acetate copolymer P-(12) Vinyl chloride-acetic acid Vinyl-maleic anhydride copolymer P-(13) Silicone resin P-(14) Silicone-alkyd resin P-(15) Phenol-formaldehyde resin P-(16) Styrene-alkyd resin P-(17) Poly-N -Vinylcarbazole These binders can be used alone or as a mixture of two or more. The thickness of the carrier generation layer 2 thus formed is preferably 0.01 μm to 20 μm, more preferably 0.05 μm to 5 μm. Ma〓〓〓〓〓
When the carrier generating layer or photosensitive layer is a dispersed type, the particle size of the bisazo compound is preferably 5 μm or less, more preferably 1 μm or less. The conductive support 1 used in the construction of the electrophotographic photoreceptor of the present invention may be a metal plate such as an aluminum plate or a stainless steel plate, or a thin metal layer such as aluminum, palladium, or gold on a support such as paper or plastic film. by lamination or vapor deposition, or by coating or vapor deposition on a support such as paper or plastic film with a layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide. used. As the intermediate layer 5 such as an adhesive layer or a barrier layer, aluminum oxide or the like is used in addition to the high molecular weight polymer used as a binder for the photosensitive layer. The conductive support used in the electrophotographic photoreceptor of the present invention may be a metal plate, a conductive polymer, a conductive compound such as indium oxide, or a thin layer of metal such as aluminum, palladium, or gold coated, vapor-deposited, or laminated. Paper that has become conductive,
Examples include plastic film. As an intermediate layer such as an adhesive layer or a barrier, in addition to the polymer used as the binder, organic polymer substances such as gelatin, casein, starch, polyvinyl alcohol, ethyl cellulose, and carboxymethyl cellulose, or aluminum oxide are used. . The electrophotographic photoreceptor of the present invention has the above-mentioned structure, and as is clear from the examples described below, has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and especially does not suffer from fatigue deterioration when used repeatedly. It is small and has excellent durability. Examples of the present invention will be specifically described below.
This does not limit the embodiments of the present invention. Example 1 A 0.05-thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) was placed on a conductive support made of aluminum foil laminated on a polyester film.
An intermediate layer of μm is provided, and exemplified compound K-(1)
A carrier-generating layer was formed by dispersing and mixing 2 parts by weight in 140 parts by weight of 1,2-dichloroethane and applying the solution to a dry film thickness of 0.5 μm. Next, 6 parts by weight of 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-pyrazoline and 10 parts by weight of polyester "Vylon 200" (manufactured by Toyobo Co., Ltd.) were mixed into 1.2 parts by weight.
- The electrophotographic photoreceptor of the present invention was prepared by dissolving it in 90 parts by weight of dichloroethane and applying this solution to a dry film thickness of 10 μm to form a carrier transport layer. The electrophotographic properties of this electrophotographic photoreceptor were measured by a dynamic method using an electrostatic copying paper tester "SP-428 model" (manufactured by Kawaguchi Electric Seisakusho). The surface of the photosensitive layer of the photoreceptor was charged with a charging voltage of -6.0KV.
The surface potential V _A when charged for a second, then the illuminance of the tungsten lamp light on the photoreceptor surface is
The exposure amount required to attenuate the surface potential V _A by half (half-reduced exposure amount) by irradiating at 35 lux.
E1/2 (lux·sec) and the surface potential (residual potential) V _R after exposure with an exposure amount of 30 lux·sec were determined. In addition, similar measurements were repeated 100 times.
The results are shown in Table 1.

[Table] Comparative Example 1 A comparative photoreceptor was prepared in the same manner as in Example 1 except that the following bisazo compound was used as a carrier generating substance. 〓〓〓〓〓
When this comparative electrophotographic photoreceptor was measured in the same manner as in Example 1, the results shown in Table 2 were obtained.

[Table] As is clear from the above results, the electrophotographic photoreceptor of the present invention is extremely superior in sensitivity, residual potential, and repetition stability compared to the comparative electrophotographic photoreceptor. Example 2 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 1 except that exemplified compound K-(2) was used as a carrier generating substance. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, the results shown in Table 3 were obtained.

[Table] Example 3 Aluminum was vapor-deposited on a polyester film, and then the intermediate layer used in Example 1 was provided, and on top of that, 2 parts by weight of exemplified compound K-(5) was added to 140 parts by weight of 1,2-dichloroethane. The dispersed and mixed liquid was applied to form a carrier generation layer so that the film thickness after drying was 0.5 μm. Next, p-(N·N-diethylamino)benzaldehyde-1,1-diphenylhydrazone 6
Weight part and polycarbonate “Panlite L-
1250'' (manufactured by Teijin Chemicals) and 10 parts by weight, 1.2-
A carrier transport layer was formed by applying a solution dissolved in 90 parts by weight of dichloroethane so that the film thickness after drying was 12 μm, thereby producing an electrophotographic photoreceptor of the present invention. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, V _A =-1010V,
E1/2=2.9 lux·sec, V _R =0V. Comparative Example 2 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 3, except that the following bisazo compound was used as a carrier generating substance. 〓〓〓〓〓
When the same measurements as in Example 1 were performed on this electrophotographic photoreceptor for comparison, it was found that V _A =1020V, E
1/2=7.5 lux·sec, V _R =-80V. As is clear from the above results, the electrophotographic photoreceptor of the present invention has significantly superior initial characteristics compared to the comparative electrophotographic photoreceptor. Example 4 Each of the electrophotographic photoreceptor of the present invention according to Example 3 and the comparative electrophotographic photoreceptor according to Comparative Example 2 was installed in an electrophotographic copying machine "U-Bix2000R" (manufactured by Konishiroku Photo Industry Co., Ltd.). Immediately after carrying out a durability test by repeating the charging, exposing and cleaning operations 2000 times, the same measurements as in Example 1 were carried out again. The results are shown in Table 4.

[Table] As is clear from the results, the deterioration of the characteristics of the electrophotographic photoreceptor of Comparative Example 2 was significantly greater, whereas
It can be seen that the characteristics of the electrophotographic photoreceptor of the present invention of Example 3 remained stable even after repeated charging and exposure 2000 times, with almost no change from the initial state. Example 5 2 parts by weight of Exemplary Compound K-(6) and 2 parts by weight of polycarbonate "Panlite L-1250" (manufactured by Teijin Kasei) were placed on the conductive support used in Example 1.
- A carrier generating layer was formed by dispersing and mixing a solution in 140 parts by weight of dichloroethane and applying the solution to a dry film thickness of 1 μm. Then 3-(p-methoxystyryl)-9-(p
A solution prepared by dissolving 6 parts by weight of (methoxyphenyl) carbazole and 10 parts by weight of methacrylic resin "Acrypet" (manufactured by Mitsubishi Rayon Co., Ltd.) in 90 parts by weight of 1,2-dichloroethane was prepared so that the film thickness after drying was 10 μm. A carrier transport layer was formed by coating the electrophotographic photoreceptor of the present invention. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, it was found that E1/2 = 3.0 lux·sec and V _R =0V. Example 6 On the conductive support provided with the intermediate layer used in Example 1, a 2% ethylenediamine solution of exemplified compound K-(3) was applied to a dry film thickness of 0.3 μm, and a carrier was applied. A generation layer was formed. Furthermore, 6 parts by weight of p-(N·N-diethylamino)benzaldehyde-1,1-diphenylhydrazone and 10 parts by weight of polycarbonate "Iupilon S-1000" (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were added to 1,2-dichloroethane. The electrophotographic photoreceptor of the present invention was prepared by dissolving the solution in 90 parts by weight and applying the solution to a dry film thickness of 14 μm to form a carrier transport layer. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, E1/2=2.2 lux・sec, V _R
= 0V. In addition, when this electrophotographic photoreceptor was installed in an electrophotographic copying machine "U-Bix2000R" (manufactured by Konishiroku Photo Industry Co., Ltd.) and images were copied, it was found that the image was faithful to the original, had high contrast, and had excellent gradation. A clear copy image was obtained. Even if this was repeated 10,000 times, the same copy image as the initial one was obtained. Comparative Example 3 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 6 except that the following bisazo compound was used as a carrier generating substance. When images were copied on this comparison electrophotographic photoreceptor in the same manner as in Example 6, the initial
Although the image was good, the fog gradually increased with repeated copying, and after 1000 repetitions, only a blurred image with large fog and low contrast could be obtained. Example 7 Aluminum was vapor-deposited on a polyester film, and then a 0.05 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) was provided. 3 parts by weight of exemplified compound K-(7), 6 parts by weight of 1,1-bis(4-N·N-diethylamino-2-methylphenyl)-1-phenylmethane, and polycarbonate "Panlite L-1250" (Teijin Kasei Co., Ltd.) 10 parts by weight of 1,2-dichloroethane were added to 100 parts by weight of 1,2-dichloroethane, and the mixture was well dispersed and mixed using a ball mill.
An electrophotographic photoreceptor of the present invention was prepared. This electrophotographic photoreceptor was tested using an electrostatic copying paper tester "SP-428 model" (manufactured by Kawaguchi Electric Seisakusho).
Electrophotographic characteristics were measured using a dynamic method. The surface of the photosensitive layer was charged with +6KV for 5 seconds, and then the light from the tungsten lamp was applied to the surface of the photosensitive layer so that the illuminance was 35 lux, reducing the exposure to half (E1/
2) was found to be E1/2 = 3.0 lux·sec, and the surface potential (residual potential) when an exposure amount of 30 lux·sec was applied was V _R =+3V. Comparative Example 4 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 7, except that the following bisazo compound was used as a carrier generating substance. Regarding this electrophotographic photoreceptor for comparison, Example 7
When measured in the same manner as above, E1/2=12.4
lux·sec, V _R =84 V, and compared to the electrophotographic photoreceptor of the present invention of Example 7, both sensitivity and residual potential were significantly inferior. Example 8 2 parts by weight of Exemplified Compound K-42 and 100 parts by weight of 1,2-dichloroethane were well dispersed and mixed on the conductive support provided with the intermediate layer used in Example 1, and the membrane after drying was prepared. A carrier generation layer was formed by coating to a thickness of 0.3 μm. Next, on top of that, a solution dissolved in 6 parts by weight of the following hydrazone derivative as a carrier transport substance and 10 parts by weight of polyester "Vylon 200" (manufactured by Toyobo Co., Ltd.), A carrier transport layer was formed by coating to a film thickness of 12 μm after drying, and an electrophotographic photoreceptor of the present invention was prepared. This electrophotographic photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 5 were obtained.

[Table] Comparative Example 5 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 8, except that the following bisazo compound was used as a carrier generating substance. 〓〓〓〓〓
Regarding this comparative electrophotographic photoreceptor, measurements were carried out in the same manner as in Example 1, and the results shown in Table 6 were obtained.

[Table] As is clear from the above results, the electrophotographic photoreceptor of the present invention has higher sensitivity than the comparative electrophotographic photoreceptor.
It has excellent residual potential and repeated stability. Example 9 2 parts by weight of Exemplary Compound K-15 and 100 parts by weight of 1,2-dichloroethane were well dispersed and mixed on the conductive support provided with the intermediate layer used in Example 1, and the membrane after drying was prepared. A carrier generation layer was created by coating the film to a thickness of 0.3 μm. Then 3-
6 parts by weight of (p-methoxystyryl)-9-(p-methoxyphenyl)carbazole and 10 parts by weight of polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals) were added to 90 parts by weight of 1,2-dichloroethane. A carrier transport layer was formed by applying the dissolved liquid to a dry film thickness of 10 μm, thereby producing an electrophotographic photoreceptor of the present invention. This electrophotographic photoreceptor was measured in the same manner as in Example 1 and found to be E1/2 = 2.4 lux·sec, V _R = 0V.
It was hot. Examples 10 to 12 Exemplary compounds (K-
8), (K-12), and (K-22) were used in the same manner as in Example 9, an electrophotographic photoreceptor of the present invention was prepared, and the same measurements were performed. The results shown are obtained.

[Table] As is clear from the above results, the electrophotographic photoreceptor of the present invention is extremely excellent in electrophotographic properties such as sensitivity and residual potential.

[Brief explanation of the drawing]

1 to 6 are sectional views showing examples of the mechanical structure of the electrophotographic photoreceptor of the present invention, respectively. 1... Conductive support, 2... Carrier generation layer,
3... Carrier transport layer, 4... Photosensitive layer, 5... Intermediate layer, 6... Layer containing a carrier transport substance, 7
...Carrier generating substance. 〓〓〓〓〓

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a bisazo compound represented by the following general formula [] on a conductive support. General formula [] [In the formula, R ₁ represents a hydrogen atom, a halogen atom, or a cyano group, Ph represents a substituted or unsubstituted phenylene group, and A is [Formula] [Formula] [Formula] or [Formula] and Y: hydrogen atom, hydroxy group, carboxy group, ester group thereof, sulfo group, substituted/unsubstituted carbamoyl group, or substituted/unsubstituted sulfamoyl group, Z: substituted/unsubstituted aromatic carbocycle or substituted Atom groups necessary to constitute an unsubstituted aromatic heterocycle, R ₁ : Hydrogen atom, substituted/unsubstituted alkyl group, substituted/unsubstituted amino group, carboxyl
cy group, its ester group, substituted/unsubstituted carbamoyl group, cyano group, R2: substituted/unsubstituted aryl group, _R3 : substituted/unsubstituted alkyl group, substituted/unsubstituted aryl group, _R3 : substituted/unsubstituted alkyl group, substituted/unsubstituted aryl group,
Represents an unsubstituted aralkyl group or a substituted/unsubstituted aryl group. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier-generating substance and a carrier-transporting substance, and the carrier-generating substance is a bisazo compound represented by the general formula [].