JPH02208659A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body for copying machines having high sensitivity and excellent repetitive characteristics by providing a photosensitive layer contg. at least one kind of bisazo compds. CONSTITUTION:The photosensitive layer contg. at least one kind of the bisazo compds. expressed by the formula I is provided. In the formula I, A denotes a residual coupler group expressed by the formulas II to III, etc. In the formulas II to III, Z denotes a residual group which forms an arom. polycyclic or heterocycle by condensing with a benzene ring; X1 denotes OR or NR2R3 (R1 to R3 respectively denote a hydrogen atom, alkyl group, aryl group or heterocyclic group which may be substd.); X2 denotes an alkyl group, aryl group, etc.; X3, X4 denote a hydrogen atom, cyano group, etc. The photosensitive body having the high sensitivity and excellent repetitive characteristics is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor that utilizes a novel charge-generating substance.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) include inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. dispersions, organic photoconductive materials such as poly-N-vinylcarbazole or polyvinylanthracene, organic photoconductive materials such as phthalocyanine compounds or bisazo compounds dispersed in resin binders or vacuum evaporated. Things are being used.

The photoreceptor also needs to have the function of retaining surface charge in the dark, the function of receiving light and generating charge, and the function of receiving light and transporting charge, but these functions can be achieved in three layers. A so-called single-layer type photoreceptor with a combination of two types of photoreceptors, and a so-called laminated photoreceptor with functionally separated layers: a layer that mainly contributes to charge generation, a layer that contributes to surface charge retention in the dark, and a layer that contributes to charge transport during light reception. There is a type photoreceptor. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation in this method involves charging the photoconductor in a dark place by corona discharge, forming an electrostatic latent image such as text or pictures on the original on the surface of the charged photoconductor, and forming an electrostatic latent image on the surface of the charged photoconductor. After the toner image has been transferred, the photoreceptor is subjected to static electricity removal, removal of residual toner, photostatic static removal, etc. before being reused. be done.

In recent years, electrophotographic photoreceptors using organic materials have been put into practical use due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, poly-N-vinylcarbazole and 2.
4.7-) Photoreceptor consisting of dinitrofluoren-9-one (described in U.S. Pat. No. 3,484,237), photoreceptor containing organic pigment as a main component JP-A-47-37543
(described in Japanese Unexamined Patent Publication No. 10785/1983), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (described in Japanese Patent Application Laid-open No. 10785/1985). Furthermore, many new hydrazone compounds and bisazo compounds have been put into practical use.

[Problem to be solved by the invention]

As mentioned above, organic materials have many advantages that inorganic materials do not have, but at the same time, there is still no material that fully satisfies all the characteristics required of electrophotographic photoreceptors. In particular, there were problems with photosensitivity and characteristics during repeated and continuous use.

The present invention has been made in view of the above-mentioned points, and uses a new organic material that has never been used as a charge-generating substance in the photosensitive layer, thereby achieving a copying machine with high sensitivity and excellent repeatability. The purpose of the present invention is to provide an electrophotographic photoreceptor for use in electrophotography.

[Means to solve the problem]

According to the present invention, the above objects are achieved by: 1) a photosensitive layer 20 containing at least one bisazo compound represented by the general formula (I); , 21.22 [Formula (A in R is a coupler residue represented by general formulas (V) to (X))] [In formulas (V) to (X), Z is a benzene ring Residues that form aromatic polycycles or heterocycles by condensation with, xI is O
R, or l;jNRaR3(R1, R2 and 1?
3 represents a hydrogen atom, an optionally substituted alkyl group, an aryl group, or a heterocyclic group), X.

and Xs each represent an optionally substituted alkyl group, aryl group, or heterocyclic group, and xj and X are a hydrogen atom, a cyano group, or a carbamoyl group.

represents a carboxyl group, ester group or acyl group, x
4 or X represents a hydrogen atom, an optionally substituted alkyl group, a cycloalkyl group, or an alkenyl group.

represents an aralkyl group, aryl group or heterocyclic group, xj
Right and xo are hydrogen atoms and halogen atoms, respectively.

represents a nitro group, an optionally substituted alkyl group, or an alkoxy group; Xs represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group;

represents an optionally substituted aryl group or heterocyclic group,
Y represents a residue forming an aromatic ring or a heterocycle. ] 2) Having a photosensitive layer 20, 21, 22 containing at least one of the bisazo compounds represented by the general formula (II), (■1) [In the formula (II), A represents the general formula (V) to ( It is a coupler residue represented by X). ] [In formulas (V) to (X), Z is a residue that is fused with a benzene ring to form an aromatic polycycle or a heterocycle, and X is O
R, or CNR, R, (R,, R, IJ, and R1 are
Each hydrogen atom, optionally substituted alkyl group, aryl group, or hetero I! x2 and X each represent an optionally substituted alkyl group, aryl group, or heterocyclic group; X and x6 are a hydrogen atom, a cyano group, or a carbamoyl group.

Represents a carboxyl group, ester group or acyl group,
X4 or x1 affected hydrogen atom, optionally substituted alkyl group, cycloalkyl group, alkenyl group.

represents an aralkyl group, aryl group or heterocyclic group, x7
and x6 are a hydrogen atom and a halogen atom, respectively.

represents a nitro group, an optionally substituted alkyl group, or an alkoxy group; x9 represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group;
represents an optionally substituted aryl group or heterocyclic group,
Y represents a residue forming an aromatic ring or a heterocycle. ] 3) Having a photosensitive layer 20.21.22 containing at least one type of bisazo compound represented by the general formula (III), (■) [In the formula (III), R is a hydrogen atom, an alkyl group, It represents an aryl group, alkenyl group, or aralkyl group that may have a substituent, and A represents a coupler residue represented by the general formulas (V) to (X). ] ×4 ×( [In formulas (V) to (X), Z is a residue that is fused with a benzene ring to form an aromatic polycycle or a heterocycle, and Xl is O
Rl or NR2R, (R,, R2 and Ro each represent a hydrogen atom, an optionally substituted alkyl group, an aryl group, or a heterocyclic group), x2 right and Xs each an optionally substituted alkyl group, Represents an aryl group or a heterocyclic group, and X and x6 are a hydrogen atom, a cyano group, or a carbamoyl group.

Represents a carboxyl group, ester group or acyl group, X
, or X is a hydrogen atom, an optionally substituted alkyl group, a cycloalkyl group, or an alkenyl group.

represents an aralkyl group, aryl group or heterocyclic group, X,
and X are a hydrogen atom and a halogen atom, respectively.

represents a nitro group, an optionally substituted alkyl group or an alkoxy group, xs represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group, and XI(
1 represents an optionally substituted aryl group or a heterocyclic group, and Y represents a residue forming an aromatic ring or a heterocyclic ring.

] This is achieved by

The compound represented by the general formula (I) is represented by the following chemical formula (X
By diazotizing the amino compound represented by I') by a conventional method and coupling it with the corresponding coupler in an appropriate solvent (for example, N, N dimethylformamide, dimethyl sulfoxide, etc.) in the presence of an alkali, Can be synthesized.

Specific examples of the bisazo compound represented by the general formula (I) thus obtained are as follows.

The compound represented by the general formula (II) is represented by the following chemical formula (
It can be easily synthesized by diazotizing the amino compound represented by can do.

Specific examples of the bisazo compound represented by the general formula (II) thus obtained are as follows.

The compound represented by the general formula (m) is represented by the following chemical formula (X
Diazotizing the amino compound represented by I) by a conventional method,
They can be easily synthesized by carrying out a coupling reaction with the corresponding couplers in an appropriate solvent (eg, N, N dimethylformamide, dimethyl sulfoxide, etc.) in the presence of an alkali.

Specific examples of the bisazo compound represented by the general formula (m) thus obtained are as follows.

The photoreceptor of the present invention contains the compounds represented by the above general formulas (I) to (I) in the photosensitive layer, and depending on the application of these compounds, the photoreceptor shown in FIG. 1, FIG. 2, or It can be used as shown in FIG.

1 to 3 are conceptual cross-sectional views of the photoreceptor of the present invention.
20.2i is a conductive substrate, 22 is a photosensitive layer, 3 is a charge generation material, 4 is a charge generation layer, 5 is a charge transport material, 6 is a charge transport layer, and 7 is a coating layer.

FIG. 1 shows a photosensitive layer 20 (usually a single layer type photosensitive layer) in which a compound of the general formulas ([) to (III) as a charge generating substance 3 and a charge transporting substance 5 are dispersed in a resin binder on a conductive substrate l. A structure called a body) is provided.

FIG. 2 shows a charge-generating layer 4 containing compounds of the general formulas (I) to ([11]) as a charge-generating substance 3 on a conductive substrate 1, and a charge-transporting layer mainly consisting of a charge-transporting substance 5. A photosensitive layer 21 (usually referred to as a laminated type photoreceptor) consisting of a laminated layer 6 and 6 is provided.

FIG. 3 shows an inverse layer configuration to that in FIG.

In this case, a coating layer 7 is further provided to protect the charge generation layer 4, and the photosensitive layer 22 is formed.

The reason for the two types of layer configurations shown in Figures 2 and 3 is that even if the layer configuration shown in Figure 2, which is normally used for a negative charging system, is intended to be used for a positive charging system, there is no compatible charge transport material. This is because the layer structure shown in FIG. 3 is required at the current stage as a positive charging type photoreceptor.

The photoreceptor shown in FIG. 1 can be produced by dispersing a charge generating material in a solution containing a charge transporting material and a resin binder, and applying this dispersion onto a conductive substrate.

The photoreceptor shown in Figure 2 is made by coating a conductive substrate with a dispersion obtained by dispersing particles of a charge-generating substance in a solvent or a resin binder, drying it, and then dissolving a charge-transporting substance and a resin binder thereon. Apply solution.

It can be produced by drying.

The photoreceptor shown in Figure 3 is made by coating a conductive substrate with a solution containing a charge transport substance and a resin binder.

After drying, a dispersion obtained by dispersing charge-generating substance particles in a solvent or resin binder is applied on top.

It can be produced by drying and further forming a covering layer.

The conductive substrate l serves as an electrode for the photoreceptor and at the same time serves as a support for the other layers, and may be cylindrical, plate-shaped, or film-shaped, and may be made of aluminum, stainless steel, nickel, etc. It may also be made of metal, glass, resin, or the like and subjected to conductive treatment.

The charge generation layer 4 is formed by applying a material in which 30 particles of a charge generation substance made of a compound represented by the general formulas (I) to (I[[) are dispersed in a resin binder, and is light-receptive. generates electric charge. In addition to the high charge generation efficiency, the ability to inject the generated charges into the charge transport layer 6 and the coating layer 7 is also important, and it is desirable that the charge is less dependent on the electric field and can be easily injected even in a low electric field. The charge generation layer is mainly composed of a charge generation substance, and a charge transporting substance can also be added thereto. Examples of resin binders include polycarbonate, polyester, polyamide, polyurethane, vinyl chloride, epoxy, silicone resin, diallyl phthalate resin, and butyral resin.

It is possible to use a suitable combination of polymers, copolymers, etc. of methacrylic acid esters.

The charge transport layer 6 is formed by applying a material in which a hydrazone compound, a pyrazoline compound, a stilbene compound, a triphenylamine compound, an oxazole compound, an oxadiazole compound, etc. are dissolved and dispersed as an organic charge transporting substance in a resin binder. In the dark, it functions as an insulating layer to hold the charge on the photoreceptor, and when receiving light, it functions to transport the charge injected from the charge generation layer. As the resin binder, polycarbonate, polyester, polyamide, polyurethane, epoxy, silicone resin, polymers and copolymers of methacrylic acid ester, etc. can be used.

The coating layer 7 has the function of receiving and retaining the charge of corona discharge in a dark place, and has the ability to transmit the light to which the charge generation layer is sensitive, and transmits the light upon exposure, and the charge generation layer It is necessary for the surface charge to be neutralized and annihilated by the injection of the generated charge. As the coating material, organic insulating film-forming materials such as polyester and polyamide can be used. In addition, these are machine materials, glass resins, and S
It is also possible to use a mixture of an inorganic material such as iQ□, or a material that reduces electrical resistance such as a metal or metal oxide. The coating material is not limited to organic insulating film-forming materials, but may include inorganic materials such as Sin, and metal alkoxy compounds having film-forming ability.

Furthermore, it is also possible to form metals, metal oxides, etc. by methods such as vapor deposition and sputtering. As mentioned above, it is desirable that the coating material be as transparent as possible in the wavelength region where the charge generating substance absorbs maximum light.

The thickness of the coating layer itself depends on the composition of the coating layer, but
It can be set arbitrarily within a range that does not cause adverse effects such as an increase in residual potential when used repeatedly and continuously.

[Effect]

There are no known examples of using bisazo compounds represented by the above general formulas (I) to (III) in photosensitive layers. In order to achieve the above objective, the present inventors conducted numerous experiments on these bisazo compounds while conducting intensive studies on various organic materials. The above general formulas (I) to (III
It was discovered that the use of a specific bisazo compound represented by ) as a charge-generating substance is extremely effective in improving electrophotographic properties, and a photoreceptor with high sensitivity and excellent repeatability was obtained.

〔Example〕

Examples of the present invention will be described below.

Example 1 50 parts by weight of the compound represented by Compound Seed 1 was added to 100 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.)
Part by weight, 100 parts by weight of 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2-pyrazoline (A S P P) and tetrahydrofuran (THF) solvent were kneaded in a mixer for 3 hours. A coating solution was prepared and applied onto an aluminum vapor-deposited polyester film (Aβ-PET) as a conductive substrate using a wire bar method to produce a photoreceptor so that the film thickness after drying was 15 μm. .

Example 2 First, a coating liquid was prepared by dissolving 100 parts by weight of p-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) and 100 parts by weight of polycarbonate resin (trade name Panlite L-1250, manufactured by Teijin) in methylene chloride. was applied onto an aluminum-deposited polyester film substrate by a wire bar method to form a charge transport layer such that the film thickness after drying was 15 μm. On the thus obtained charge transport layer, 50 parts by weight of the compound represented by the compound Nα2, 50 parts by weight of a polyester resin (trade name Vylon 200; manufactured by Toyobo Co., Ltd.) and a THF solvent were kneaded for 3 hours in a mixer and applied. A liquid was prepared and applied by a wire bar method to form a charge generation layer such that the film thickness after drying was approximately 0.5 μm.

Example 3 In Example 2, the charge transport substance was replaced with ABPH, and a stilbene compound, α-phenyl-4°-N,
A charge transport layer was formed using N-dimethylaminostilbene in the same manner as in Example 2, and a charge generation layer was further formed to produce a photoreceptor.

Example 4 In Example 2, a charge transport layer was formed in the same manner as in Example 2 using tri(p-tolyl)amine, which is a triphenylamine compound, instead of ABPH as the charge transport material, and charge generation was further performed. A layer was formed to produce a photoreceptor.

Example 5 In Example 2, the charge transport substance was replaced with ABPH and an oxadiazole compound, 2°5-bis(p-
A charge transport layer was formed using (diethylaminophenyl)-1,3°4-oxadiazole in the same manner as in Example 2, and a charge generation layer was further formed to prepare a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.

The surface potential VS (volts) of the photoreceptor is +6. Ok
This is the initial surface potential when corona discharge of V is performed for 10 seconds to positively charge the surface of the photoreceptor, and then the surface potential is V when held in the dark for 2 seconds with corona discharge stopped.
Measure d (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to find the time (seconds) it takes for vd to be halved, and calculate the half-attenuation exposure amount E1/2 (lux seconds). And so. Further, the surface potential when white light with an illuminance of 2 lux was irradiated for 10 seconds was defined as the residual potential V (volt).

As seen in Table 1, Examples 1.2.3.4.5 had good half-attenuation exposure and residual potential.

Example 6 Compound 10 represented by the above compounds Nα3 to N1122
0 parts by weight of each was mixed with 100 parts by weight of polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) and a THF solvent for 3 hours using a mixer to prepare a coating solution, and coated on an aluminum support so as to have a thickness of about 0.5 μm. A charge generation layer was formed by coating the respective materials. On top of this, apply approximately 15μ of the ABPH coating solution obtained in the same manner as in Example 2.
A photoreceptor was prepared by coating the film in an amount of m.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric. The results are shown in Table 2.

The surface potential V (volt) of the photoreceptor is -6.0kV in the dark.
This is the initial surface potential when corona discharge is performed for 10 seconds to negatively charge the surface of the photoreceptor, and the surface potential V is the surface potential when the photoreceptor surface is then held in the dark for 2 seconds with corona discharge stopped.
(volts), and then the illuminance 2 on the photoreceptor surface.
Calculate the time (seconds) it takes for vd to be halved after irradiating the white light of lux. Half-attenuation exposure amount El/□ (lux seconds)
And so.

As seen in Table 2, the bisazo compound has 3 to 2
The half-attenuation exposure amount E +72 was also good for the photoreceptor using No. 2 as the charge generating material.

Example 7 50 parts by weight of the compound represented by the compound NCL31 was added to polyester resin (trade name: Vylon 200, manufactured by Toyobo) 1
00 parts by weight and 1-phenyl-3-(p-diethylaminostyryl)-511)-diethylaminophenyl)-2
- 100 parts by weight of pyrazoline (A S P A photoreceptor was prepared by coating using a bar method so that the film thickness after drying was 15 μm.

Example 8 First, 100 parts of p-diethylaminobenzaldehyde diphenylhydrazone (8BPH) and 10 parts of polycarbonate resin (trade name Panlite L-1250, manufactured by Kijin) were added.
A coating liquid prepared by dissolving 0 parts by weight in methylene chloride was applied onto an aluminum-deposited polyester film substrate by a wire bar method to form a charge transport layer so that the film thickness after drying was 15 μl. On the thus obtained charge transport layer, 50 parts of the compound represented by the compound Nα32 and 50 parts of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.)
A coating solution was prepared by kneading parts by weight and a THF solvent in a mixer for 3 hours, and the coating solution was coated by a wire bar method to form a charge generation layer so that the film thickness after drying was 0.5 μm.

Example 9 In Example 8, the charge transport substance was replaced with ABPH, and a stilbene compound, α-phenyl-4′-N,
N-': A charge transport layer was formed using methylaminostilbene in the same manner as in Example 8, and a charge generation layer was further formed to produce a photoreceptor.

Example 1O In Example 8, the charge transport substance was changed to ABPH and the triphenylamine compound To! J(p-)'
A charge transport layer was formed using amine in the same manner as in Example 8, and a charge generation layer was further formed to produce a photoreceptor.

Example 11 In Example 8, the charge transport substance was replaced with 8BPH and an oxadiazole compound, 2°5-bis(p-
A charge transport layer was formed using (diethylaminophenyl)-1,34-oxadiazole in the same manner as in Example 8, and a charge generation layer was further formed to produce a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.

The surface potential V s (volts) of the photoreceptor is +6.
This is the initial surface potential when the photoreceptor surface is positively charged by performing OkV corona discharge for 10 seconds, and the surface potential vd (volt) when the photoreceptor surface is then held in the dark for 2 seconds with corona discharge stopped. After measurement, the surface of the photoreceptor was further irradiated with white light with an illuminance of 2 lux, and the time (seconds) until vd was halved was determined as the half-attenuation exposure amount E+/z (lux seconds). Further, the surface potential when white light with an illuminance of 2 lux was irradiated for 10 seconds was defined as the residual potential V (volt).

Table 3 As seen in Table 3, Examples 7.8.9. +0゜1
Sample No. 1 had good half-attenuation exposure and residual potential.

Example 12 Compound 100 represented by Nα52 from Compound 33
The weight part is polyester resin (product name: Byron 2).
00: manufactured by Toyobo) 3 with 100 parts by weight and THF solvent
A coating solution was prepared by kneading with a time mixer, and the coating solution was coated onto an aluminum support to a thickness of about 0.5 μm to form a charge generation layer. On top of this, a coating liquid of ABPH obtained by the same method as in Example 8 was applied to a thickness of about 15 μm.
A photoreceptor was prepared by applying the following coatings.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric. The results are shown in Table 4.

The surface potential Vs (volts) of the photoreceptor is -6.0k in the dark.
This is the initial surface potential when the surface of the photoreceptor is negatively charged by performing a corona discharge of V for 10 seconds, and the surface potential when the photoreceptor surface is then held in the dark for 2 seconds with corona discharge stopped.
Measure d (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to find the time (seconds) it takes for vd to be halved, and calculate the half-attenuation exposure amount El/2 (lux seconds). And so.

As seen in Table 4, the bisazo compound Nα33
The half-attenuation exposure amount E 1/2 was also good for the photoreceptor using .about.52 as the charge generating material.

Table 4 Example 13 50 parts by weight of the compound represented by the compound Nα61 was added to 10 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.)
0 parts by weight and 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2-
A coating solution was prepared by kneading 100 parts by weight of pyrazoline (A S P P) and tetrahydrofuran (THF) with a solvent for 3 hours using an electric mixer, and the coating solution was applied onto an aluminum-deposited polyester film (^1-PET), which is a conductive substrate. A photoreceptor was prepared by coating using a wire bar method so that the film thickness after drying was 15 μm.

Example 14 First, a coating liquid was prepared by dissolving 100 parts by weight of p-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) and 100 parts by weight of polycarbonate resin (trade name Panlite L-1250, manufactured by Kijin) in methylene chloride. was coated on an aluminum-deposited polyester film substrate by a wire bar method to form a charge transport layer so that the film thickness after drying was 15 .mu.-. On the charge transport layer thus obtained, 50 parts by weight of the compound represented by Compound Ma 62, 50 parts by weight of a polyester resin (trade name Pylon 200, manufactured by Toyobo Co., Ltd.) and THE solvent were kneaded in a mixer for 3 hours. Prepare the coating liquid and apply it using the wire bar method.
A charge generation layer was formed so that the film thickness after drying was 0.5 μl.

Example 15 In Example 14, the charge transport material was replaced with ABPH and a stilbene compound, α-phenyl-4'-N
, N-dimethylaminostilbene was used to form a charge transport layer in the same manner as in Example 14, and a charge generation layer was further formed to produce a photoreceptor.

Example 16 In Example 14, the charge transport substance was changed to ABPH, and a triphenylamine compound, TO! j(p-)
! A charge transport layer was formed using amine in the same manner as in Example 14, and a charge generation layer was further formed to produce a photoreceptor.

Example 17 In Example 14, the charge transport substance was replaced with ABPH and an oxadiazole compound, 2°5-bis(p
-diethylaminophenyl)-1,3°4-oxadiazole was used to form a charge transport layer in the same manner as in Example 14,
Furthermore, a charge generation layer was formed to produce a photoreceptor.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester Wir SP-428J manufactured by Kawaguchi Electric.

The surface potential vs (volt) of the photoreceptor is +6.0kV in the dark.
This is the initial surface potential when corona discharge is performed for 10 seconds to positively charge the surface of the photoreceptor, and the surface potential when the photoconductor surface is then held in the dark for 2 seconds with corona discharge stopped is vd.
(volts), and then the illuminance 2 on the photoreceptor surface.
Calculate the time (seconds) it takes for vd to be halved by irradiating the lux white light and find the half-attenuation exposure amount E +/2 (lux・
seconds). Further, the surface potential when white light with an illuminance of 2 lux was irradiated for 10 seconds was defined as the residual potential V (volt).

Table 5 As seen in Table 5, Examples! 3.14.15゜1
Samples No. 6 and No. 17 had good half-attenuation exposure and residual potential.

Example 18 Compound 1 represented by the above compounds Nα63 to Nα129
A coating solution was prepared by kneading 00 parts by weight of each of 00 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) and a THF solvent for 3 hours in a mixer. A charge generation layer was formed by applying the coating. On top of this, apply about 1 liter of the ABPH coating solution obtained in the same manner as the chief priest in Example 14.
A photoreceptor was prepared by coating the film to a thickness of 5 μm.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric. The results are shown in Table 6.

The surface potential V (volt) of the photoreceptor is -6, OkV in the dark.
This is the initial surface potential when corona discharge is performed for 10 seconds to negatively charge the surface of the photoreceptor, and then the surface potential is V when the corona discharge is stopped and the surface is held in the dark for 2 seconds.
(volts), and then the illuminance 2 on the photoreceptor surface.
Calculate the time (seconds) it takes for vd to be halved by irradiating the white light of Lux, and find the half-attenuation exposure amount E, (lux seconds)
And so.

As seen in Table 6, the bisazo compound PkL6
The half-attenuation exposure amount E1/2 was also good for the photoreceptor using No. 3 to No. 3 to No. 129 as the charge generating material.

Table 6 (Part 1) Table (Part 2) Table 6 (Part 3) l Conductive substrate, 3 Charge generating substance, 4 Charge generating layer,
5 charge transport material, 6 charge transport layer, 7 coating layer, 20.
21.22 Photosensitive layer.

〔Effect of the invention〕

According to the present invention, since the compounds represented by the general formulas (I) to (III) are used as a charge generating substance on a conductive substrate, it is possible to achieve high sensitivity and repeatability even in positive and negative charging. A photoreceptor with excellent characteristics can be obtained. Furthermore, if necessary, it is possible to add a coating layer to the surface to improve durability.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are conceptual sectional views showing different embodiments of the photoreceptor of the present invention.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one bisazo compound represented by the general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In formula (I), A is a coupler residue represented by general formulas (V) to (X). ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (V) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VIII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IX) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X) [In formulas (V) to (X) , Z is a residue that is fused with a benzene ring to form an aromatic polycycle or heterocycle, X_1 is OR_1 or NR_2R_3 (R_1, R_2 and R_3 are each a hydrogen atom, an optionally substituted alkyl group, an aryl group, or represents a heterocyclic group), X_2
and X_5 are each an optionally substituted alkyl group,
Represents an aryl group or a heterocyclic group, X_3 and X_
6 represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group or an acyl group, and X_4 or X_1_1 represents a hydrogen atom, an optionally substituted alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group or represents a heterocyclic group, X_7 and X_8 each represent a hydrogen atom, a halogen atom, a nitro group, an optionally substituted alkyl group or an alkoxy group, and X_9
represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group, X_1_0 represents an optionally substituted aryl group or heterocyclic group, and Y represents a residue forming an aromatic ring or a heterocyclic ring. represent. 2) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one type of bisazo compound represented by the general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (II) [In formula (II), A is a coupler residue represented by general formulas (V) to (X). ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (V) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VIII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IX) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X) [In formulas (V) to (X) , Z is a residue that is fused with a benzene ring to form an aromatic polycycle or heterocycle, X_1 is OR_1 or NR_2R_3 (R_1, R_2 and R_3 are each a hydrogen atom, an optionally substituted alkyl group, an aryl group, or represents a heterocyclic group), X_2
and X_5 are each an optionally substituted alkyl group,
Represents an aryl group or a heterocyclic group, X_3 and X_
6 represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group, or an acyl group, and X_4 or X_1_1 is a hydrogen atom, an optionally substituted alkyl group,
Represents a cycloalkyl group, alkenyl group, aralkyl group, aryl group, or heterocyclic group; X_7 and X_8 each represent a hydrogen atom, a halogen atom, a nitro group, an optionally substituted alkyl group or an alkoxy group; represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group, X_1_0 represents an optionally substituted aryl group or heterocyclic group, and Y represents a residue forming an aromatic ring or a heterocyclic ring. 3) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one type of bisazo compound represented by the general formula (III). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In formula (III), R represents a hydrogen atom, an alkyl group, an aryl group that may have a substituent, an alkenyl group, an aralkyl group, and A represents a general formula (V) ~ The coupler residue represented by (X) is shown. ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (V) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VIII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IX) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X) [In formulas (V) to (X) , Z is a residue fused with a benzene ring to form an aromatic polycycle or heterocycle, X_1 is OR_1 or NR_2R_3 (R_1, R_2 and R_3 are each a hydrogen atom, an optionally substituted alkyl group, an aryl group, or represents a heterocyclic group), X_2
and X_5 are each an optionally substituted alkyl group,
Represents an aryl group or a heterocyclic group, X_3 and X_
6 represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group, or an acyl group, and X_4 or X_1_1 is a hydrogen atom, an optionally substituted alkyl group,
Represents a cycloalkyl group, alkenyl group, aralkyl group, aryl group, or heterocyclic group; X_7 and X_8 each represent a hydrogen atom, a halogen atom, a nitro group, an optionally substituted alkyl group or an alkoxy group; represents an optionally substituted alkyl group, aryl group, carboxyl group, or ester group, X_1_0 represents an optionally substituted aryl group or heterocyclic group, and Y represents a residue forming an aromatic ring or a heterocyclic ring. ]