JPS6135548B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor 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 with photosensitive layers mainly composed of inorganic photoconductors such as selenium, zinc oxide, and cadmium oxide have been widely used. However, these have poor sensitivity, heat resistance, and moisture resistance. 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 containing an organic photoconductive compound as a main component are relatively easy to manufacture, are expensive to manufacture, and can be shaped into either a cylindrical drum or a sheet. There is something
It has many advantages 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, and have attracted a lot of attention in recent years. There is. As such an organic photoconductive compound, poly-N-vinylcarbazole is known, and a charge transfer complex formed from poly-N-vinylcarbazole and a Lewis acid such as 2,4,7-trinitro-9-fluorenone is mainly used. Electrophotographic photoreceptors having a photosensitive layer as a component have already been put into practical use. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and printing durability. On the other hand, there are known functionally separated electrophotographic photoreceptors of laminated or dispersed type in which the carrier generation function and the carrier transport function of the photoconductive function are respectively assigned to separate substances. 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. Furthermore, among photoconductive organic dyes and pigments, it has been proposed to use photoconductive organic dyes and pigments with particularly excellent carrier-generating properties as carrier-generating substances, such as the perylene pigment described in U.S. Pat. Publication No. 48-30513, Japanese Unexamined Patent Publication No. 1983-
Publication No. 95033, Japanese Unexamined Patent Publication No. 12742-1983, Japanese Unexamined Patent Publication No. 1987-12742
Azo compounds described in JP-A-116040, JP-A-54-20737, and US Pat. No. 4,052,210 are already known. However, these azo compounds are not necessarily satisfactory in terms of characteristics such as sensitivity, residual potential, and stability when used repeatedly, and the selection range of carrier transport materials is also limited. The reality is that nothing that fully satisfies the wide-ranging demands of photographic processes has yet to be 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 have discovered that a bisazo compound represented by the following general formula [] can act as an active ingredient on a photoreceptor, and have completed the present invention. General formula [] A-N=N-Ar ₁ -CX ₁ = CX ₂ -CX ₃ = CX ₄ -Ar ₂ -N=N-A In the formula, Ar ₁ and Ar ₂ are substituted and unsubstituted aromatics, respectively. It represents a group carbocyclic group, preferably a substituted or unsubstituted phenyl group or a naphthyl group, and more preferably a substituted or unsubstituted phenyl group. Substituents for these groups include, for example, substituted/unsubstituted alkyl groups, substituted/unsubstituted alkoxy groups, halogen atoms, cyano groups, carboxy groups, ester groups thereof, sulfo groups, acylamino groups, carbamoyl groups, and acyl groups. , an acyloxy group, a sulfonamide group, a sulfamoyl group, a sulfone group, etc., but preferred are substituted/unsubstituted alkyl groups, substituted/unsubstituted alkoxy groups, cyano groups, and halogen atoms. X ₁ , X ₂ , X ₃ and X ₄ each represent a hydrogen atom or an electron-withdrawing group, preferably a hydrogen atom, a cyano group, a halogen atom, a carboxy group, or a nitro group. 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 carbamoyl group, or a substituted or unsubstituted sulfamoyl group, preferably a substituted or unsubstituted carbamoyl group. base

[Formula] Substituted/unsubstituted string Rufuamoyl group

[Formula], R ₄ is a hydrogen atom, a substituted or unsubstituted lower alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted phenyl group, and R ₅ is a hydrogen atom, a substituted or unsubstituted phenyl group having 1 to 4 carbon atoms. Substituted lower alkyl group, substituted or unsubstituted aromatic carbocyclic group (for example, substituted or unsubstituted phenyl group, substituted or unsubstituted naphthyl group, substituted or unsubstituted anthryl group, etc.), or substituted or unsubstituted represents an aromatic heterocyclic group (for example, a substituted/unsubstituted carbazolyl group, a substituted/unsubstituted dibenzofuryl group, etc.). Substituents for these groups include, for example, those having 1 to 4 carbon atoms.
Alkyl groups, halogen atoms such as chlorine atoms and bromine atoms, lower alkoxy groups having 1 to 4 carbon atoms, hydroxy groups, aryloxy groups such as phenoxy groups and naphthoxy groups, acyloxy groups, carboxy groups, their ester groups, carbamoyl groups , an acyl group, a sulfo group, a sulfamoyl group, an amino group, an acylamino group, a sulfonamido group, a cyano group, a nitro group, etc., but preferably an alkyl group having 1 to 4 carbon atoms, a chlorine atom, a bromine atom, etc. These include a halogen atom, a lower alkoxy group having 1 to 4 carbon atoms, a cyano group, and a nitro group. Z is an atomic group necessary to form a substituted/unsubstituted aromatic carbocycle or a substituted/unsubstituted aromatic heterocycle, and specifically, for example, a substituted/unsubstituted benzene ring, a substituted/unsubstituted Naphthalene ring, substituted and
Represents a group of atoms forming an unsubstituted indole ring, a substituted/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 , with preference given to halogen atoms, sulfo groups, and sulfamoyl groups. R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group,
Substituted/unsubstituted amino groups, carboxy groups, ester groups thereof, substituted/unsubstituted carbamoyl groups, and cyano groups, preferably hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, and cyano groups. R ₂ is a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted phenyl group. Examples of substituents for these groups include R ₄ , R ₅
A series of substituents such as those mentioned above are listed, but preferably a halogen atom, a carbon number of 1 to
4 alkyl group, and a low-strength alkoxy group having 1 to 4 carbon atoms. R ₃ is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, and preferably represents an alkyl group having 1 to 4 carbon atoms or a phenyl group. That is, in the present invention, the general formula []
By using the bisazo compound represented by the formula as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor, or by utilizing only the excellent carrier generation ability of the bisazo compound of the present invention, generation and transport of carriers can be improved. By using it as a carrier generating material in a function-separated electrophotographic photoreceptor in which separate substances are used, the film has excellent physical properties and electrophotographic properties such as charge retention, sensitivity, and residual potential, and it does not cause stress even when used repeatedly. It is possible to create an electrophotographic photoreceptor that exhibits less deterioration and exhibits robust and stable characteristics against heat, light, and the like. Examples of the bisazo compound useful in the present invention represented by the above general formula [] include those having the following structural formula.
The zo compound is not limited. 〓〓〓〓〓
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The above bisazo compounds can be easily synthesized by known methods. For example, Synthesis Example 1 (Synthesis of Exemplary Compound K-1) 1,4-bis-[p-nitrophenyl]-1,3-butadiene synthesized by the method described in Makromol Chem., 84, 64-79 (1965) In the presence of alcohol, reduction with tin and hydrochloric acid yields 1,4-bis-[p
-aminophenyl]-1,3-butadiene was obtained. 2.36 g (0.01 mol) of the 1,4-bis-[p-aminophenyl]-1,3-butadiene thus obtained was dispersed in a mixture of 10 ml of concentrated hydrochloric acid and 10 ml of water, and 1.52 g (0.022 mol) of sulfurous acid A solution of sodium dissolved in 5 ml of water was cooled with ice to an internal temperature of 0°C to 5°C.
The mixture was added dropwise while maintaining the temperature at °C, and the mixture was stirred at the same temperature for 1 hour. After the reaction, a small amount of residue was separated, 20 ml of 42% borohydride was added to the solution, and the precipitate was collected, washed with water, and thoroughly dried. The obtained tetrazonium salt was dissolved in 50 ml of N.N-dimethylformamide to prepare a tetrazonium salt solution to be used in the next reaction. Next, 5.27 g (0.02 mol) of 2-hydroxy-3-naphthoic acid anilide (naphthol AS) and 2.4 g of triethanolamine were dissolved in 400 ml of N/N-dimethylformamide, and the internal temperature was adjusted to 10 to 13°C under ice cooling. The above-prepared tetrazonium salt solution was added dropwise while maintaining the temperature, and the mixture was further 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, washed with N.N-dimethylformamide and then with acetone, and dried to obtain 4.5 g of the target bisazo compound. Melting point: 300℃ or higher ν=1680cm ^-1 (amide absorption) in infrared absorption spectrum and m/e in FD-MASS spectrum
The appearance of a molecular ion peak of =784 confirmed that the target substance had been synthesized. Synthesis Example 2 (Synthesis of Exemplified Compound K-25) 1 obtained by condensation of p-nitrocinnamaldehyde and p-nitrobenzyl cyanite in alcohol in the presence of piperidine according to the method described in Organic Reaction Vol 15, 204・4-bis-(p-nitrophenyl)-1-cyano-1.3
-Butadiene is reduced with tin and hydrochloric acid in the presence of alcohol, and 1,4-bis-(p-aminophenyl)-1
-Cyano-1,3-butadiene was obtained. The 1,4-bis-(p-
2.61 g (0.01 mol) of (aminophenyl)-1-cyano-1,3-butadiene was added to a mixture of 10 ml of concentrated hydrochloric acid and 10 ml of water and dispersed to give 1.52 g (0.022 mol).
A solution of sodium sulfite dissolved in 5 ml of water was added dropwise under ice-cooling while maintaining the internal temperature at 0 to 5°C, and the mixture was stirred and reacted at the same temperature for 1 hour. After the reaction, a small amount of residue was filtered, and 20 ml of a 42% aqueous borohydrogen fluoride solution was added to the solution, and the precipitate was collected, washed with water, and thoroughly dried. Obtained tetrazo〓〓〓〓〓
The tetrazonium salt was dissolved in 50 ml of N.N-dimethylformamide to prepare a tetrazonium salt solution 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-dimethylformamide, and the internal temperature was adjusted to 0 to 5 ml under ice cooling. The tetrazonium salt solution prepared above was added dropwise while maintaining the temperature at °C, and the mixture was further stirred at the same temperature for 2 hours, and further stirred and reacted at room temperature for 2 hours. After that, the precipitate was collected, and N/N-dimethylformamide was added.
Next, the target bisazo compound 4.0 was obtained by washing with acetone and drying. Melting point 300℃ or higher Infrared absorption spectrum shows ν=2200cm ^-1 (CN
absorption), ν=1680cm ^-1 (amide absorption) and FD−
The appearance of molecular ion P with m/e=809 in the mass spectrum confirmed that the target substance had been synthesized. Synthesis Example 3 (Synthesis of Exemplary Compound K-30) 2-hydroxy-3-naphthoic acid-2',4'-dimethylanilide (naphthol AS-MX) 5.83g
(0.02 mol) N・N-dimethylformamide 700ml
Add 20 g of sodium acetate, and gradually add 50 ml of the N·N-dimethylformamide solution of the tetrazonium salt (0.01 mol) prepared in Synthesis Example 2 while keeping the internal temperature at 10 to 13°C under ice cooling. Ta. The mixture was further stirred at the same temperature for 2 hours, and further stirred and reacted at room temperature for 2 hours. After the reaction, collect the precipitate and add N.
By washing with N-dimethylformamide, then water, and then acetone, and drying, 4.5 g of the target bisazo compound was obtained. Melting point: 300℃ or higher Infrared absorption spectrum: ν=2200cm ^-1 (CN
absorption), ν=1680cm ^-1 (amide absorption) and FD−
It was confirmed that the target substance was synthesized because a peak of molecular ion +1 with m/e = 866 appeared in the MASS spectrum. Synthesis Example 4 (Synthesis of Exemplified Compound K-73) According to the method described in Organie Reaction Vol 15, 204, m-nitro-α-bromocinnamaldehyde and p-nitrobenzyl cyanide were condensed in alcohol in the presence of piperidine. The thus obtained 3-bromo-1-cyano-1-(p-nitrophenyl)-4-(m-nitrophenyl)-1.3-
Butadiene was reduced with tin and hydrochloric acid in the presence of alcohol, and 3-bromo-1-cyano-1-(p-aminophenyl)-4-(m-aminophenyl)-1.
3-Butadiene was obtained. 4.0 g (0.01 mol) of 3-bromo-1-cyano-1-(p-aminophenyl)-4-(m-aminophenyl)-1,3-butadiene thus obtained was mixed with 15 ml of hydrochloric acid and 15 ml of water. dispersed in a mixture of
An aqueous solution of 1.52 g (0.022 mol) of sodium nitrite dissolved in 5 ml of water was added dropwise under ice-cooling while maintaining the internal temperature at 0 to 5°C, and the reaction was further stirred at the same temperature for 1 hour. After the reaction, a small amount of residue was separated, and 30 ml of a 42% borohydrogen fluoride aqueous solution was added to the solution to collect the precipitate, washed with water, and thoroughly dried. The obtained tetrazonium salt was dissolved in 50 ml of N.N-dimethylformamide to prepare a tetrazonium salt solution to be used in the next reaction. Next, 6.16 g of 2-hydroxy-3-naphthoic acid-3'-nitroanilide (naphthol AS-BS)
(0.02 mol), 400 ml of triethanolamine 5.4 g
The tetrazonium salt solution prepared above was added dropwise while maintaining the internal temperature at 10 to 13°C under ice-cooling, and further diluted at the same temperature for 2 hours.
The reaction was stirred for hours. Thereafter, the deposited precipitate was collected, washed with N.N-dimethylformamide, then with acetone, and dried to obtain 6.2 g of the target bisazo compound. Melting point 300℃ or higher Infrared absorption spectrum shows ν=2200cm ^-1 (CN absorption), ν=1680cm ^-1 (amide absorption) and FD−
It was confirmed that the target substance had been synthesized because an isotope peak group caused by the molecular ion M ⁺ =879 appeared in the MASS spectrum. 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 provided on a conductive support. It can be manufactured by In addition, as another method, particularly excellent photoconductivity of the bisazo compound of the present invention may be used.
By using it as a carrier generating substance that utilizes its carrier generating ability, and using it together with a carrier generating substance that can effectively act in combination with this, it is also possible to create a so-called functionally separated type electrophotographic photoreceptor, such as a laminated or dispersed type. It is. Various types of functional 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 generation 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. Figures 2 and 4
As shown in the figure, 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 mainly composed of a carrier transporting substance is formed on the conductive support 1. It may be provided directly or via the intermediate layer 5. When the bisazo compound of the present invention is used as a carrier generating substance, carrier transporting substances that can be used in combination with it include electron-accepting substances that easily transport electrons such as trinitrofluorenone or tetranitrofluorenone, as well as polyN
- Polymers having heterocyclic compounds in their side chains, such as vinyl carbazole, or triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted Examples include electron-donating substances that easily transport holes, such as chalcone 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 via an intermediate layer such as an adhesive layer or a barrier layer if necessary, 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 as necessary to mix and disperse the resulting dispersion and then applied. 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 conductivity, and is electrically insulating. preferable. 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 Polyvinyl 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-vinyl acetate-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. Further, when the carrier generation layer or the 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 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 layer, in addition to the polymer used as the binder, organic polymer substances such as gelatin, casein, starch, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, or aluminum oxide are used. It will be done. The electrophotographic photoreceptor of the present invention has the above-mentioned structure, and as is clear from the examples described later, it has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and particularly shows little fatigue deterioration when used repeatedly. It 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.
A μm thick intermediate layer is provided, and exemplified compound K-1 is added thereon.
A carrier-generating layer was formed by dispersing and mixing a double part in 140 parts by weight of 1,2-dichloroethane and applying the solution to a dry film thickness of 0.5 μm. Next, 1.2 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.) −
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 VA when charged for seconds, then the illuminance of the tungsten lamp light on the photoreceptor surface.
Exposure amount required to attenuate the surface charge VA by half (half-reduced exposure amount) E by irradiating at 35 lux
The surface potential (residual potential) VR after exposure with an exposure dose of 1/2 (lux·sec) and 30 lux·sec was 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 the 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, the intermediate layer used in Example 1 was provided, and 2 parts by weight of Exemplary Compound K-3 was dispersed and mixed in 140 parts by weight of 1,2-dichloroethane. The solution was applied so that the thickness after drying was 0.5 μm to form a carrier generation layer. 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, VA=-1050V, E
1/2=2.7 lux・sec, VR=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 comparative electrophotographic photoreceptor was measured in the same manner as in Example 1, VA=-1020V,
E1/2=7.5 lux・sec, VR=-80V. As is clear from the above results, the electrophotographic photoreceptor of the present invention has significantly superior initial characteristics than the comparative electrophotographic photoreceptor. Example 4 The electrophotographic photoreceptor of the present invention according to Example 3 and the comparative electrophotographic photoreceptor according to Comparative Example 2 were each installed in an electrophotographic copying machine "U-Bix200R" (manufactured by Konishiroku Photo Industry Co., Ltd.). After carrying out a durability test by repeating the charging, exposing and cleaning operations 2000 times, the same measurements as in Example 1 were immediately 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 electrophotographic photoreceptor of the present invention of Example 3 has stable characteristics with almost no change from the initial state even after repeated charging and exposure 2000 times. Example 5 2 parts by weight of Exemplary Compound K-6 and 2 parts by weight of polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals) 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 1,2-dichloroethane and applying the solution to a dry film thickness of 1 μm. Then, 3-(p-methoxystyryl)-9-
6 parts by weight of (p-methoxyphenyl)carbazole and 10 parts by weight of methacrylic resin "Acripet" (manufactured by Mitsubishi Rayon) were mixed with 1,2-dichloroethane.
A carrier transport layer was formed by coating a solution dissolved in 90 parts by weight so that the film thickness after drying was 10 μm, thereby producing an electrophotographic photoreceptor of the present invention. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, E1/2=31 lux・sec, VR=0V
It was hot. Example 6 On the conductive support provided with the intermediate layer used in Example 1, a 2% ethylenediamine solution of Exemplified Compound K-25 was applied to a dry film thickness of 0.3 μm to form a carrier generation layer. did. Furthermore, 1.2 parts by weight of 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.) - A carrier transport layer was formed by dissolving the solution in 90 parts by weight of dichloroethane and coating it to a film thickness of 14 μm after drying, thereby producing an electrophotographic photoreceptor of the present invention. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, E1/2=2.3 lux・sec,
VR=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 images were faithful to the original, had high contrast, and had excellent gradation. An excellent and 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. Regarding this electrophotographic photoreceptor for comparison, Example 6
When the image was copied in the same manner as above, the initial image was good, but as the copies were repeated, the fog gradually increased, and by the 1000th repetition, the image was no longer clear with large fog and low contrast. All I could get was an image. 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-42, 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 and 100 parts by weight of 1,2-dichloroethane
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The electrophotographic photoreceptor of the present invention was prepared by adding the liquid to the parts by weight and thoroughly dispersing and mixing with a ball mill so that the film thickness after drying was 10 μm. The electrophotographic properties of this electrophotographic photoreceptor were measured by a dynamic method using an electrostatic copying paper testing device "Model SP-428" (manufactured by Kawaguchi Electric Seisakusho). The surface of the photosensitive layer was charged with +6KV for 5 seconds, and then the light from a tungsten lamp was applied to the surface of the photosensitive layer so that the illuminance was 35 lux to reduce the exposure to half (E1/2).
When we calculated E1/2=3.3 lux・sec,
Furthermore, the surface potential (residual potential) when an exposure amount of 30 lux·sec was applied was VR=+4V. 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, VR=84 V, and was significantly inferior to the electrophotographic photoreceptor of the present invention of Example 7 in both sensitivity and residual potential. Example 8 2 parts by weight of Exemplary Compound K-76 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 film thickness after drying was A carrier generation layer was formed by applying the film to a thickness of 0.3 μm. Next, 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.) were dissolved thereon. A carrier transport layer was formed by applying the solution to a dry film thickness of 12 μm, thereby producing an electrophotographic photoreceptor of the present invention. 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 electrophotographic photoreceptor for comparison, Example 1
When measurements were carried out in the same manner as above, the results shown in Table 6 were obtained.

[Table] As is clear from the above results, the electrophotographic photoreceptor of the present invention is superior to the comparative electrophotographic photoreceptor in terms of sensitivity, residual potential, and repetition stability. Example 9 2 parts by weight of Exemplary Compound K-45 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 film thickness after drying was A carrier generation layer was created by applying the film to a thickness of 0.3 μm. Then, as a carrier transport material, 3
-(p-methoxystyryl)-9-(p-methoxyphenyl)carbazole 6 parts by weight and polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals)
A carrier transport layer was formed by coating a solution prepared by dissolving 10 parts by weight of 1,2-dichloroethane in 90 parts by weight of 1,2-dichloroethane so that the film thickness after drying was 10 μm, thereby producing an electrophotographic photoreceptor of the present invention. When this electrophotographic photoreceptor was measured in the same manner as in Example 1, E1/2=2.4 lux・sec, VR=
It was 0V. Examples 10 to 14 Exemplary compound K-3 as a carrier generating substance,
An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 9 except that K-26, K-39, K-42, and K-69 were used, and the same measurements were performed. The results shown are obtained.

[Table] Example 15 An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 3 except that exemplified compound K-71 was used as a carrier generating substance. When this photoreceptor was measured in the same manner as in Example 1, it was found that E1/2 = 2.4 lux·sec and VR = -2V. Comparative Example 6 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 10, except that the following bisazo compound was used as a carrier generating substance. This comparative photoreceptor was measured in the same manner as in Example 1, and found that E1/2
= 8.8 lux・sec, VR-85V. 〓〓〓〓〓
As is clear from the above results, the electrophotographic photoreceptor of the present invention is significantly superior in characteristics such as sensitivity and residual potential than the comparative electrophotographic photoreceptor.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views showing examples of the mechanical configuration 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 [] A-N=N-Ar ₁ -CX ₁ = CX ₂ -CX ₃ = CX ₄ -Ar ₂ -N=N-A [In the formula, Ar ₁ and Ar ₂ are substituted and unsubstituted aromatics, respectively. represents a group carbocyclic group, X ₁ , X ₂ , X ₃ , and X ₄ each represent a hydrogen atom or an electron-withdrawing group, 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/unsubstituted Atom groups necessary to constitute an aromatic heterocycle, R ₁ : hydrogen atom, substituted/unsubstituted alkyl group, substituted/unsubstituted amino group, carboxy group, ester group thereof, substituted/unsubstituted carbamoyl group, Cyano group, _R2 : substituted/unsubstituted aryl group, _R3 : substituted/unsubstituted alkyl group, substituted/unsubstituted aralkyl group, or 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 [].