JPH0234016B2 - DENSHISHASHINYOKANKOTAI - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photoreceptor for electrophotography. Specifically, the present invention relates to a highly sensitive electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance. Conventionally, the photosensitive layer of electrophotographic photoreceptors contains selenium,
Inorganic photoconductive materials such as cadmium sulfide and zinc oxide were widely used. In recent years, research has progressed on the use of organic photoconductive substances, typified by polyvinylcarbazole, in photosensitive layers of electrophotographic photoreceptors, and some of them have been put into practical use. Compared to inorganic photoconductive materials, organic photoconductive materials have advantages such as being lighter, easier to form a film, easier to manufacture photoreceptors, and depending on the type, transparent photoreceptors can be manufactured. has advantages. Although they have many advantages, organic photoconductive materials are not often used in electrophotographic photoreceptors because they are inferior to inorganic materials in terms of sensitivity and durability. As a result of intensive research into organic photoconductive materials that provide electrophotographic photoreceptors with high sensitivity and high durability, the present inventors found that charge generation in the photosensitive layer consisting of a charge generation layer and a charge transfer layer The present invention was achieved by discovering that a layer containing a specific bisazo compound is suitable and also has excellent color sensitivity, particularly red reproducibility. Regarding red color reproducibility, halogen lamps and tungsten lamps are often used as light sources in copying machines, but in this case, because they are incandescent lamps, the spectral energy distribution is larger in the long wavelength range, and the length of the photoreceptor If the wavelength range distribution sensitivity is high,
When making copies, originals that are red, such as vermilion, appear poorly. Therefore, it is desirable for the photoreceptor to have relatively low spectral sensitivity in the long wavelength range. Furthermore, it is not preferable to apply a filter to the light source in order to improve red color reproducibility, as this results in a decrease in sensitivity. Therefore, an electrophotographic photoreceptor with excellent red reproducibility has been desired, but as described below, at least one of the two azo groups that are chromophores is set at the meta position with respect to the azole ring. By doing so, the maximum absorption wavelength was shifted to a shorter wavelength compared to the one in which two azo groups were substituted at the para positions, and the red sensitivity was surprisingly improved. The gist of the present invention is to provide a laminated electrophotographic photoreceptor having a photosensitive layer consisting of a charge generation layer and a charge transfer layer on a conductive support, in which the charge generation layer has the general formula () [In the formula, A represents a phenylene group or a naphthylene group which may have a substituent, and X is -o-
or

[Formula] (R represents a hydrogen atom, an alkyl group, or a phenyl group which may have a substituent). ] An electrophotographic photoreceptor characterized by containing a bisazo compound represented by the following. To explain the present invention in detail, the bisazo compound contained in the charge generation layer of the electrophotographic photoreceptor of the present invention is represented by the above general formula (), and for example,
The following positional isomers (Ia) to (Id) are included. In the general formula (), A represents a phenylene group or a naphthylene group which may have a substituent. Such substituents include, for example, a methyl group,
Ethyl group, n-propyl group, i-propyl group, n
- Alkyl groups such as butyl group, i-butyl group, n-hexyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group; hydroxy group; nitro group; cyano group; fluorine atom, chlorine atom,
Halogen atoms such as bromine and iodine atoms; carboxyl groups; alkoxycarbonyl groups such as ethoxycarbonyl groups; carbamoyl groups; aryloxy groups such as phenoxy groups; aralkoxy groups such as benzyloxy groups; aryloxycarbonyls such as phenyloxycarbonyl groups Examples include groups. Among them, alkyl groups, alkoxy groups, nitro groups, halogen atoms, hydroxy groups, carboxyl groups, particularly methyl groups, methoxy groups, nitro groups, chlorine atoms, and hydroxy groups are mentioned. As A, specifically, for example, a phenylene group, tolylene group, xylylene group, chlorophenylene group, bromophenylene group,
Nitrophenylene group, methoxyphenylene group, o
-naphthylene group, etc., and phenylene group and tolylene group are particularly preferred when sensitivity and durability are taken into consideration. In the general formula (), X is -o- or

[Formula] (R represents a hydrogen atom, an alkyl group, or a phenyl group which may have a substituent), and specific examples of R include a methyl group, an ethyl group, a propyl group, a butyl group, etc. Alkyl group; examples include phenyl group, tolyl group, methoxyphenyl group, chlorophenyl group, nitrophenyl group, and the like. In consideration of sensitivity and durability, X is particularly preferably an oxygen atom. The bisazo compound of the present invention includes, for example, a coupler component represented by the following general formula (-a) and/or (-b) and a structural formula

It can be easily synthesized by a coupling reaction of a diamine represented by the formula with a tetrazonium salt.

【formula】

[Formula] (wherein A has the same meaning as in the above general formula ()) Such a coupling reaction is usually carried out using water and/or dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, etc. The reaction may be carried out in an organic solvent at a reaction temperature of 30° C. or lower for about 1 to 10 hours. The coupler components represented by the general formulas (-a) and (-b) are, for example, according to the following reaction formula (1),
3-Hydroxynaphthalic anhydride () and aromatic diamine () are heated in a solvent such as acetic acid,
Obtained by dehydration condensation. (J.Chem.
Soc., 1937 , 1764) Reaction equation (1) The coupler component obtained by the above synthesis method is
Although it is obtained as a mixture of isomers of general formulas (-a) and (-b), either isomer can be used in the present invention. In the present invention, other methods for obtaining the coupler component include a method using 3-hydroxynaphthalic acid or an ester thereof in place of 3-hydroxynaphthalic anhydride () in the above reaction formula (1);
Examples include a method of reductive condensation using a monoamino-mononitro compound instead of an aromatic diamine, or a method of condensing with an aromatic diamine using 3-sulfonaphthalic anhydride and then hydrolyzing the sulfonic acid group. . In this way, the azo compounds of the present invention are obtained, especially 2-hydroxy and 5-hydroxy-7H- obtained by a dehydration condensation reaction between 3-hydroxynaphthalic anhydride and substituted or unsubstituted o-phenylenediamine. Benzimidazo [2,1-a]
Benz[de]isoquinolin-7-one or substituted products thereof and 2-(3'-aminophenyl)-5
―[3″(4″)-aminophenyl]-1,3,4-
A bisazo compound represented by the following general formula () obtained by a coupling reaction of oxadiazole with a tetrazonium salt is preferred. (In the formula, R ⁴ represents a hydrogen atom or a methyl group.) The electrophotographic photoreceptor of the present invention includes a charge generation layer containing one or more bisazo compounds represented by the general formula () and a charge generation layer containing one or more bisazo compounds represented by the general formula (). It has a photosensitive layer consisting of a moving layer. The charge generation layer can be formed, for example, by coating a coating solution obtained by dissolving or dispersing a bisazo compound represented by the above general formula () alone or together with a binder polymer in an appropriate solvent on a conductive support and drying the coating solution. can get. Butylamine, butylamine,
Basic solvents such as ethylenediamine; ethers such as tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane, and diethylene glycol dimethyl ether; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N,N-dimethylformamide, Aprotic polar solvents such as acetonitrile, N-methylpyrrolidone, dimethylsulfoxide;
Examples include alcohols such as methanol, ethanol, and isopropanol; esters such as ethyl acetate, methyl formate, and methyl cellosolve acetate; and chlorinated hydrocarbons such as dichloroethane and chloroform. These solvents may be used alone or in combination of two or more. When using a binder polymer, it is desirable to use one that dissolves the polymer. As the binder polymer, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic ester, and methacrylic ester;
Examples include polyester, polycarbonate, polysulfone, polyvinyl butyral, phenoxy resin, cellulose ester, cellulose ether, urethane resin, and epoxy resin. The amount of binder polymer used is usually in the range of 0.1 to 5 times the weight of the bisazo compound. In addition, the bisazo compound has a thickness of 1 μm in the binder.
It is preferable to make it exist in the following fine particle state.
The thickness of the charge generation layer is usually several μm or less, especially 1 μm.
The following are preferred. As the conductive support on which the charge generation layer is applied, any of those employed in well-known electrophotographic photoreceptors can be used. Specific examples include metal drums and sheets made of aluminum, copper, etc., and laminates and vapor deposits of these metal foils. Further examples include plastic films, plastic drums, paper, paper tubes, etc., which are coated with a conductive substance such as metal powder, carbon black, copper iodide, or polymer electrolyte together with a suitable binder to conductivity treatment. In addition, metal powder, carbon black,
Examples include plastic sheets and drums that contain conductive substances such as carbon fibers and are made conductive. A charge transfer layer is formed by stacking on the charge generation layer. Conversely, a charge transfer layer may be formed on a conductive support and a charge generation layer may be laminated on top of the charge transfer layer, but since the thickness of the charge generation layer is usually thin, it is difficult to protect the charge generation layer from wear and dirt. Therefore, the former type is often used. The charge transport layer is a layer that transports charge carriers generated in the charge generation layer and contains a charge carrier transport medium. Charge carrier transfer media are generally classified into two types: electron transfer media and hole transfer media, and both can be used in the photosensitive layer of the photoreceptor of the present invention, and a mixture thereof can also be used. As an electron transfer medium, an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group, or an ester group, such as 2,4,7-trinitrofluorenone, 2,
Examples include nitrated fluorenone such as 4,5,7-tetranitrofluorenone and tetracyanoquinodimethane. In addition, as a hole transfer medium, an electron-donating organic photoconductive compound such as
Heterocyclic compounds such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole, aniline derivatives, hydrazine derivatives,
Examples include hydrazone, diphenyl acrolein hydrazone, or polymers having a group consisting of these compounds in the main chain or side chain (polyvinylcarbazole, polyglycidylcarbazole). Among these, hydrazone compounds represented by the following general formula () or () are particularly preferred as compounds to be contained in the charge transfer layer. (In the formula, R ¹ represents an alkyl group, substituted alkyl group or aralkyl group, R ² represents an alkyl group,
It represents a substituted alkyl group, allyl group, phenyl group, naphthyl group or aralkyl group, and Y represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. ) (In the formula, Z ¹ , Z ² and Z ³ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a phenoxy group or an arylalkoxy group, and R is a hydrogen atom,
It represents a lower alkyl group, allyl group, phenyl group or aralkyl group, m and l represent 1 or 2, and n represents 0 or 1. ) Specific examples of R ¹ in general formula () include methyl group,
Alkyl groups such as ethyl group, propyl group, butyl group, hexyl group; Substituted alkyl groups such as 2-hydroxyethyl group and 2-chloroethyl group; benzyl group,
Examples include aralkyl groups such as phenethyl groups. In consideration of sensitivity and durability, alkyl groups such as methyl, ethyl, propyl, and butyl groups are particularly preferred. Specific examples of ^R2 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group,
Examples include alkyl groups such as heptyl group and octyl group; allyl group; phenyl group; naphthyl group; aralkyl group such as benzyl group and phenethyl group. In consideration of sensitivity and durability, methyl, ethyl, phenyl, and naphthyl groups are particularly preferred. Specific examples of Y include a hydrogen atom, an alkyl group such as a methyl group and an ethyl group; a methoxy group; an alkoxy group such as an ethoxy group; and a halogen atom such as a chlorine atom and a bromine atom. In consideration of sensitivity and durability, hydrogen atoms are particularly preferred. In the general formula (), Z ¹ , Z ² and Z ³ are hydrogen atoms;
Lower alkyl groups such as methyl, ethyl, propyl, butyl, hexyl; lower alkoxy groups such as methoxy, ethoxy, putoxy; phenoxy; arylalkoxy groups such as benzyloxy and phenethyloxy; , R ³ represents a hydrogen atom; a lower alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, or a hexyl group; an allyl group; a phenyl group; an aralkyl group such as a benzyl group or a phenethyl group. m and l represent 1 or 2, n is 0 or 1
represents. In the general formula (), Z ¹ and Z ² are lower alkyl groups or lower alkoxy groups, Z ³ is a hydrogen atom,
Preferably, R ³ is a phenyl group. The hydrazone compound represented by the general formula () can be easily produced by a known method. For example, the following general formula () (In the formula, Z ¹ and Z ² , l, m and n have the same meanings as in the general formula ()). In an organic solvent inert to the reaction such as formamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, etc., and in some cases, a reaction promoter such as p-toluenesulfonic acid, benzenesulfonic acid, hydrochloric acid, sulfuric acid, potassium acetate, sodium acetate, etc. In the presence of the following general formula () (In the formula, R ³ and Z ³ have the same meanings as above.) or its hydrochloride or sulfate at 10 to 200°C, preferably
It is obtained by reacting at a temperature of 20 to 100°C. In addition, acroleins represented by the general formula () shown above and the following general formula () (In the formula, Z ³ has the same meaning as above.) and benzene, toluene, chlorobenzene, alcohol, acetone, N,N-
dimethylformamide, dimethyl sulfoxide,
React in an organic solvent inert to the reaction such as tetrahydrofuran or dioxane, or in the presence of a reaction accelerator such as p-toluenesulfonic acid, benzenesulfonic acid, hydrochloric acid, sulfuric acid, potassium acetate, sodium acetate, etc. According to the following general formula (XI) (wherein Z ¹ , Z ² , Z ³ , m, l and n have the same meanings as in the general formula ()) is produced, and then the following general formula (XII) R ₃ - W ... (XII) (In the formula, R ³ has the same meaning as in the above general formula (), and W represents a halogen atom such as a chlorine atom, a bromine atom, an iodine atom, etc.) Using alkylating agents, allylating agents, aralkylating agents, or dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, it is possible to react with tetrahydrofuran, dioxane, N,N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, etc. in an active organic solvent in the presence of a deoxidizing agent such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, pyridine, trimethylbenzylammonium hydroxide, etc.
The hydrazone represented by the general formula () can be produced by reacting at a temperature of .degree. Acrolein of the general formula (), which is one of the raw materials, is produced, for example, by the following known reaction. The hydrazone compounds represented by the general formulas () and () may be used alone, or may be mixed in any proportion. When used in combination, a hydrazone compound of the general formula (20) is usually used.
It is preferable to mix 80 to 20 parts by weight of the hydrazone compound of the general formula () to 80 parts by weight, particularly in an equivalent weight ratio. When the charge carrier transport medium is a low-molecular compound, the charge transport layer is formed in a state in which it is dissolved in a binder polymer. The charge carrier transfer medium is normally used in an amount of 0.2 to 1.5 times, preferably 0.3 to 1.2 times, the weight of the binder polymer. As the binder polymer, a polymer similar to that used for the charge generation layer is used, and it is dissolved in a solvent together with the charge carrier transfer medium to prepare a coating solution, which is coated and dried to form the charge transfer layer. The thickness of the charge transfer layer is 5 to 50 μm, preferably 10 to 30 μm. Of course, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer. Suitable sensitizers include Lewis acids and dyes that form charge transfer complexes with organic photoconductive materials. Examples of Lewis acids include chloranil, 2,3-dichloro-
1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5
- Quinones such as nitroanthraquinone, 2-chloroanthraquinone, phenanthrenequinone, 4
-Aldehydes such as nitrobenzaldehyde,
9-Benzoylanthracene, indandione,
3,5-dinitrobenzophenone, 3,3',5,
Ketones such as 5′-tetranitrobenzophenone,
Acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene, terephthalal malononitrile, 4-nitrobenzalmalononitrile, and 4-(p-nitrobenzoyloxy)benzalmalononitrile; ; Electron withdrawal of phthalides such as 3-benzalphthalide, 3-(α-cyano-p-nitrobenzal) phthalide, 3-(α-cyano-p-nitrobenzal)-4,5,6,7-tetrachlorophthalide, etc. Examples include sexual compounds. Examples of dyes include triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, cyanine dyes, pyrylium salts, thiapyrylium salts, and benzopyrylium salts. It will be done. Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known plasticizer in order to improve film formability, flexibility, and mechanical strength. Examples of the plasticizer include phthalate esters, phosphate esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, aromatic compounds such as methylnaphthalene, and the like. It goes without saying that it may also include an adhesive layer, an intermediate layer, and a transparent insulating layer, if necessary. The photoreceptor using the bisazo compound of the present invention has high sensitivity and good color sensitivity, and when used repeatedly, there is little variation in sensitivity and chargeability, little optical fatigue, and extremely high durability. It is something. In particular, the bisazo compound of the present invention has low spectral sensitivity in the long wavelength region, and has excellent color sensitivity to white light sources such as halogen lamps and tungsten lamps, which are often used as light sources for electrophotographic copying machines, and particularly red reproduction. Excellent sex. Furthermore, the photoreceptor of the present invention can be widely used in electrophotographic applications such as photoreceptors for printers using lasers and cathode ray tubes (CRTs) as light sources in addition to electrophotographic copying machines. Next, the present invention will be explained in more detail using reference examples and examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition,
In Reference Examples and Examples, [parts] indicate [parts by weight]. Reference Example 1 10 parts of 3-hydroxynaphthalic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 5.7 parts of methyl-0-phenylenediamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were mixed in a mixed solvent of 23 parts of glacial acetic acid and 115 parts of nitrobenzene. The mixture was stirred and reacted at the boiling point of acetic acid for 2 hours. After the reaction, the mixture was cooled to room temperature, and the precipitated crystals were collected, thoroughly washed with methanol, and then dried. The obtained crystals were yellow in color and did not melt at temperatures below 320°C. Elemental analysis and infrared absorption spectroscopy revealed that this crystal was an isoquinoline compound represented by the following structural formula. The yield is 11 parts,
The elemental analysis values were as follows. Calculated value as C ₁₉ H ₁₂ O ₂ N ₂ ; C76.01% H4.00% N9.33% Actual value; C75.83% H3.91% N9.26%

【formula】

[Formula] 3 parts of the above isoquinoline compound are dissolved in 300 parts of N-methylpyrrolidone at a temperature of 0-5°C, and then 2-(m-aminophenyl)-5-(p-aminophenyl)-1,3,4-oxa A solution of diazole tetrazonium borohydrofluoride in N-methylpyrrolidone was added dropwise and stirred for 30 minutes. Next, 7 parts of a saturated aqueous solution of sodium acetate was slowly added dropwise at the same temperature to cause a coupling reaction. After the dropwise addition was completed, the same temperature was maintained for 2 hours and stirring was continued, after which the solution was taken out.
After washing with water, methanol, and N-methylpyrrolidone, it was dried. The obtained compound had a deep purple color and did not melt at temperatures below 320°C. Elemental analysis values and infrared absorption spectroscopy showed that this compound was fixed as the target bisazo compound consisting of four isomers represented by the following structural formula.
The yield was 1.8 parts, and the elemental analysis values were as follows. Calculated value as C ₅₂ H ₃₀ N ₁₀ O ₅ ; C71.38% H3.46% N16.01% Actual value; C70.53% H3.54% N15.72% The bisazo compounds of the present invention used in the following Examples were synthesized according to this Reference Example or a method similar thereto. Examples 1 to 6 The above general formula (where G is shown in Table 1)
) bisazo compound with a structure corresponding to 0.45
1 part was dispersed with 30 parts of cyclohexanone using a sand grinder, and 0.9 part of polyester (manufactured by Toyobo Co., Ltd., trademark Vylon 200) was added and dissolved therein. The obtained dispersion of the bisazo compound was coated with a film applicator onto an aluminum vapor-deposited layer deposited on a polyester film having a thickness of 100 μm so that the dry film thickness was 0.3 g/m ² and then dried. On the charge generation layer thus obtained, 80 parts of N-ethylcarbazole-3-aldehyde diphenylhydrazone and 100 parts of methacrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trademark DIANAL BR-85) were dissolved in 550 parts of toluene. The solution was applied to a dry film thickness of 13 μm to form a charge transfer layer. In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was obtained. The sensitivity of these photoreceptors is half-decreased exposure (E1/
The values of 2) are shown in Table 1. The half-decrease exposure amount was measured using an electrostatic copying paper tester (Model SP-428 manufactured by Kawaguchi Denki Seisakusho) for the photoreceptor. First, it was charged by -6.5 KV corona discharge in a dark place, and then exposed to white light with an illuminance of 5 lux, and the amount of exposure required for the surface potential to attenuate to half of the initial surface potential was determined.

[Table] Examples 7 to 12 In place of the bisazo compound represented by the general formula () used in Examples 1 to 6, a bisazo compound having a structure corresponding to the above general formula () in which G is shown in Table 2 was used. A charge generation layer was prepared in the same manner as in Example 1, and a charge transfer layer was prepared in the same manner as in Example 1, to obtain an electrophotographic photoreceptor having a two-layer photosensitive layer. The sensitivity of these photoreceptors is half-decreased exposure (E1/
The values of 2) are shown in Table 2. The half-decreased exposure amount was determined by the same method as in Examples 1-6.

【table】

[Table] Example 13 Comparative Examples 1 and 2 A comparison was made of the spectral sensitivity ratio when the two azo groups of the bisazo compound are both at the meta position and when both are at the para position with respect to the azole ring. . The light source for sensitivity measurement was subjected to spectroscopy using a monochromator (Shimadzu Boschulom diffraction grating type strong monochromator, manufactured by Shimadzu Corporation), and the photoconductor of Example 9 was analyzed.
The spectral sensitivities at 550nm and 650nm were measured and compared. As sensitivity, the half-decreased exposure (E1/2) was measured using a photometer (Obtical Power Meter Model 44XL, manufactured by Photodyne). Structural formula below with substitution position changed to para position for comparison [G in the formula is

[expression] and

Represents [formula]. ] A charge generation layer and a charge transport layer were formed in the same manner as in Example 9 using a bisazo compound represented by
The spectral sensitivity of the obtained photoreceptor was measured in the same manner (Comparative Example 1). In addition, the following structural formula Example except that a bisazo compound represented by
The spectral sensitivity of the photoreceptor obtained in the same manner as in Example 13 was measured (Comparative Example 2). The results are shown in Table 3.

[Table] Comparing Example 13 and Comparative Example 1, it is found that when the azo group is substituted at the meta position, the spectral sensitivity is shifted to shorter wavelengths than when it is at the para position, and the photoreceptor of the present invention It can be seen that the spectral sensitivity in the long wavelength region is relatively low and the red color reproducibility is excellent. To further confirm this, we used a copying machine (Sharp SF-
750), and a color control patch (manufactured by Kodatsu Co., Ltd.) was used to copy the photoreceptor of Example 13. The photoreceptor of Example 13 produced copies with approximately the same density for each of the colors cyan, magenta, and red. Obtained. Furthermore, when a document with a red stamp was copied, the red stamp was also clearly copied, and it was confirmed that the red color reproduction was excellent. Comparative example 2
The photoreceptor had extremely poor red color reproducibility. Example 14 A charge generation layer was prepared in the same manner as in Example 1 using the bisazo compound used in Example 1, and β,β-bis(p-methoxyphenyl)acrolein-N,N-diphenyl was added thereon. A solution of 80 parts of enylhydrazone and 100 parts of methacrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trademark DIANAL BR-85) dissolved in 550 parts of toluene was applied to a dry film thickness of 13 μm.
A charge transfer layer was formed. The thus obtained electrophotographic photoreceptor having a two-layer photosensitive layer had a half-decrease exposure amount of 2.0 lux·sec. This photoreceptor was irradiated with light from a tungsten lamp to examine its stability against light. Light of 3000 lux was irradiated for 5 minutes, and immediately the charging and exposure steps were repeated using the electrostatic copying paper tester model SP-428. One cycle dark decay is 0.4 seconds using static method.
The test was carried out under the condition of light attenuation of 2 seconds (illuminance 400 lux). The surface potential immediately after light irradiation was 93% of that before irradiation, returned to 97% after the fifth repetition, and remained almost unchanged even after 100 repetitions. Considering measurement errors, it is thought that there is almost no decrease in surface potential due to light irradiation. The residual potential (surface potential at an exposure dose of 50 lux·sec) before irradiation was -2V, and did not change even after 100 repetitions of tungsten light irradiation. There was no change in sensitivity under the above measurement conditions. As described above, the photoreceptor of the present invention is extremely stable against light. Example 15 A charge generation layer was prepared in the same manner as in Example 1 using the bisazo compound used in Example 1, and the N-ethylcarbazole-3-aldehyde diphenyl used in Example 1 was placed on this charge generation layer. hydrazone
45 parts of β,β-bis(p-methoxyphenyl)acrolein-N,N-diphenylhydrazone used in Example 14 and 100 parts of polycarbonate resin (manufactured by Mitsubishi Chemical Corporation, trademark Novarex 7030A) were mixed with 550 parts of toluene. The dry film thickness of the solution dissolved in
It was applied to a thickness of 13 μm to form a charge transfer layer. The half-decrease exposure amount of the electrophotographic photoreceptor having the two-layer photosensitive layer thus obtained is 1.8 lux.
It was hot in sec. This photoreceptor was prepared in the same manner as in Example 13.
The results of measuring the spectral sensitivity at 550 nm and 650 nm are as follows, and it can be seen that the spectral sensitivity in the long wavelength region is relatively low and the red color reproducibility is excellent. 550nm 650nm E1/2 (μJ/cm ² ) 0.524 2.94 Relative sensitivity 1.0 0.18 When copying was carried out in the same manner as in Example 13 using this photoreceptor, copies with approximately the same density were obtained for each color. It was confirmed that the red stamp was clearly copied and the red color reproduction was excellent.

Claims (1)

[Scope of Claims] 1. A laminated electrophotographic photoreceptor having a photosensitive layer consisting of a charge generation layer and a charge transfer layer on a conductive support, wherein the charge generation layer has the general formula () [In the formula, A represents a phenylene group or a naphthylene group which may have a substituent, and X is -O-
or [Formula] (R represents a hydrogen atom, an alkyl group, or a phenyl group which may have a substituent). ] An electrophotographic photoreceptor characterized by containing a bisazo compound represented by the following. 2 The charge transfer layer has the general formula () (In the formula, R ¹ represents an alkyl group, substituted alkyl group or aralkyl group, R ² represents an alkyl group,
It represents a substituted alkyl group, allyl group, phenyl group, naphthyl group or aralkyl group, and Y represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. 2. The electrophotographic photoreceptor according to claim 1, which contains a hydrazone compound represented by: 3 The charge transfer layer has the general formula () (In the formula, Z ¹ , Z ² and Z ³ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a phenoxy group or an arylalkoxy group, and R ³ represents a hydrogen atom,
Represents a lower alkyl group, allyl group, aralkyl group or phenyl group which may have a substituent,
m and l represent 1 or 2, and n represents 0 or 1. 2. The electrophotographic photoreceptor according to claim 1, which contains a hydrazone compound represented by: 4 The charge transfer layer has the above general formulas () and ()
The electrophotographic photoreceptor according to claim 1, which contains a hydrazone compound represented by the following in an arbitrary proportion.