JPH05134435A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body excellent in sensitivity and reliability. CONSTITUTION:A thiophene deriv. represented by formula I is used as an electric charge transferring material in a photosensitive layer and a bisazo compd. represented by formula II as an electric charge generating material. In the formula I, each of R1 and R2 is H, alkyl or ayl and each of R3-R6 is H, alkoxy, alkyl or aryl. In the formula II, R7 is halogen, alkyl or alkoxy, R8 is alkyl, R9 is H, cyano, carbamoyl, carboxyl ester or acyl and R10, is H, halogen, nitro, alkyl or alkoxy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoconductor used in electrophotographic printers, copying machines,
In particular, it relates to a charge generating substance and a charge transporting substance used for the photosensitive layer.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive material for an electrophotographic photoreceptor (hereinafter also referred to as a photoreceptor), an inorganic photoconductive substance such as selenium or a selenium alloy, an inorganic photoconductive substance such as zinc oxide or cadmium sulfide is used as a resin. An organic photoconductive substance such as poly-N-vinylcarbazole or polyvinylanthracene dispersed in a binder, or an organic photoconductive substance such as a phthalocyanine compound or a bisazo compound is dispersed in a resin binder. The thing and the thing which vacuum-deposited are used. In addition, the photoreceptor must have the function of retaining surface charge in the dark, the function of receiving light to generate charge, and the function of receiving light to transport charge as well. A so-called single-layer type photoconductor having a function and a so-called layered type photoconductor in which a layer mainly functioning to generate charges and a layer having a function separation in a surface charge in a dark place and a layer contributing to charge transport during light reception are laminated. I have a body. For example, the Carlson method is applied to the image formation by the electrophotographic method using these photoconductors. Image formation by this method is charging by corona discharge to a photoconductor in a dark place, formation of an electrostatic latent image such as characters and pictures of an original on the charged surface of the photoconductor, electrostatic latent image formed Of the developed toner image and fixing of the developed toner image to a support such as paper.After the toner image has been transferred, the photoconductor is neutralized, residual toner is removed, and light is neutralized before reuse. To be done.

In recent years, electrophotographic photoreceptors using organic materials have been put into practical use because of their advantages such as flexibility, thermal stability and film-forming property. For example, a photoreceptor composed of poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (described in US Pat. No. 3,484,237), a photoreceptor containing an organic pigment as a main component (special Kaisho 47
-37543), a photoreceptor containing a eutectic complex composed of a dye and a resin as a main component (JP-A-47-10735).
No. publication).

[0004]

However, organic materials have many advantages over inorganic materials, but at the same time, none of them sufficiently satisfy all the characteristics required for electrophotographic photoreceptors. However, there is a strong demand for a photoreceptor having high sensitivity and excellent repeatability. The present invention has been made in view of the above points, and an object thereof is to provide an electrophotographic photoconductor for a copying machine which eliminates the above-mentioned drawbacks by a novel combination of a charge generating substance and a charge transporting substance and is excellent in sensitivity and repeatability. To aim.

[0005]

According to the first aspect of the present invention, there is provided a photosensitive layer on a conductive substrate, and the photosensitive layer comprises a thiophene derivative represented by the general formula [I] as a charge transporting substance. It contains a bisazo compound represented by the general formula [II] as a charge generating substance.

[0006]

[Chemical 10] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.)

[0007]

[Chemical 11] (R ₇ represents a halogen atom, an alkyl group, an alkoxy group, R ₈ represents an optionally substituted alkyl group, R ₉ represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group ester group or an acyl group, R ₁₀ represents a hydrogen atom, a halogen atom, a nitro group or an optionally substituted alkyl group or alkoxy group.)

According to the second invention, a photosensitive layer is provided on a conductive substrate, and the photosensitive layer is represented by the general formula [I] as a charge transporting substance.
Containing a thiophene derivative represented by and a bisazo compound represented by the general formula [III] as a charge generating substance

[0009]

[Chemical 12] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.)

[0010]

[Chemical 13] (R ₁₁ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group or an alkoxy group, R ₁₂ represents an optionally substituted alkyl group, an aryl group or an aromatic heterocyclic group, and R ₁₃ Is a hydrogen atom, a cyano group,
It represents a carbamoyl group, a carboxyl group, an ester group or an acyl group, and R ₁₄ and R ₁₅ each represent a hydrogen atom, a halogen atom, a nitro group or an optionally substituted alkyl group or alkoxy group. )

According to the third invention, a photosensitive layer is provided on a conductive substrate, and the photosensitive layer is represented by the general formula [I] as a charge transporting substance.
A thiophene derivative represented by and a polycyclic quinone compound represented by the general formula [IV] as a charge generating substance,

[0012]

[Chemical 14] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.)

[0013]

[Chemical 15] (X represents a hydrogen atom, a halogen atom, or a cyano group, and m represents an integer of 0 to 4.)

According to the fourth invention, a photosensitive layer is provided on a conductive substrate, and the photosensitive layer is represented by the general formula [I] as a charge transporting substance.
And a squarylium compound represented by the general formula [V] as a charge generating substance.

[0015]

[Chemical 16] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.)

[0016]

[Chemical 17] (R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ are each an optionally substituted alkyl group, aryl group, aralkyl group, or alkenyl group, and R ₁₆ and R ₁₇ , or R ₁₈ and R ₁₉ may form a ring. Well, R
₂₀ and R ₂₁ are a hydrogen atom, a halogen atom, a hydroxy group,
Represents an alkyl group and an alkoxy group. )

According to a fifth aspect of the invention, a photosensitive layer is provided on a conductive substrate, and the photosensitive layer has the general formula [I] as a charge transporting substance.
This can be achieved by including a thiophene derivative represented by and a metal-free phthalocyanine or titanyl phthalocyanine as a charge generating substance.

[0018]

[Chemical 18] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.)

General formulas [I], [II], [III], [I
Specific examples of the compounds represented by V] and [V] are as follows. In Tables 1 and 2, -Ph is a phenyl group,
-Me is a methyl group, -SPh is a 2-thienyl group, -Et
Represents an ethyl group, respectively.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Chemical 19]

[0023]

[Chemical 20]

[0024]

[Chemical 21]

[0025]

[Chemical formula 22]

[0026]

[Chemical formula 23]

[0027]

[Chemical formula 24]

[0028]

The novel combination of the charge transport material and the charge generating material makes it possible to obtain a photoreceptor having high sensitivity and excellent repeatability, although the details are unknown.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are cross-sectional views showing an electrophotographic photosensitive member according to an embodiment of the present invention. 1 is a conductive substrate, 2 is a charge generation layer, 3 is a charge transport layer, 4 is a photosensitive layer, 5
Is a surface coating layer, and the photosensitive layer is a function separation type in which a charge generation layer and a charge transport layer are separated. The photosensitive layer of FIG. 1 is a negative charging type in which a charge generating layer and a charge transporting layer are laminated in this order, and the photosensitive layer of FIG. 2 is a positive charging type in which a charge transporting layer and a charge generating layer are laminated in the opposite order to that of FIG. Is. The conductive substrate 1 serves not only as an electrode of the photoconductor but also as a support for each of the other layers, which may be cylindrical, plate-shaped, or film-shaped, and is made of aluminum, stainless steel, nickel, or the like. A metal, glass, resin, or the like that has been subjected to a conductive treatment may be used. The charge generation layer 2 is formed by vacuum deposition of an organic photoconductive substance or by coating a material in which particles of an organic photoconductive substance are dispersed in a resin binder, and receives light to generate charges. Further, it is desirable that the charge generation efficiency is high, and at the same time, the property of injecting the generated charges into the charge transport layer 3 is important, the electric field dependency is small, and the injection is good even in a low electric field.

Since the charge generation layer only needs to have a charge generation function, its thickness is determined by the light absorption coefficient of the charge generation substance and is generally 5 μm or less, preferably 1 μm or less. The charge generation layer may be mainly composed of a charge generation material and a charge transport material may be added to the charge generation layer. As the resin binder, it is possible to appropriately combine and use polycarbonate, polyester, polyamide, polyurethane, epoxy, polyvinyl butyral, phenoxy, silicone resin, methacrylic acid ester polymer, copolymer and the like. The charge transport layer 3 is a coating film made of a material in which an organic charge transport material is dispersed in a resin binder, holds an electric charge of a photoreceptor as an insulating layer in a dark place, and is injected from a charge generating layer at the time of receiving light. It exerts the function of transporting electric charges. Resin binders include polycarbonate, polyester, epoxy, silicone resin,
Polymers and copolymers of polystyrene and methacrylic acid ester are used, and the compatibility with the charge transport material is important in addition to mechanical, chemical and electrical stability and adhesion. The thickness of the charge transport layer is preferably in the range of 3 to 50 μm in order to maintain a practically effective surface potential,
More preferably, it is 10 to 40 μm.

The surface coating layer 5 is excellent in durability against mechanical stress and is composed of a chemically stable substance. It has a function of receiving and holding a corona discharge charge in a dark place, and has a charge. It is necessary that the generating layer has a property of transmitting light to which it is sensitive, transmits light during exposure, reaches the charge generating layer, and receives the injection of the generated charge to neutralize and eliminate the surface charge. Further, as described above, it is desirable that the coating material is as transparent as possible in the wavelength region of the maximum light absorption of the charge generating substance. As the coating material of the surface coating layer, modified silicone resin, acrylic modified silicone resin,
Epoxy-modified silicone resin, alkyd-modified silicone resin, polyester-modified silicone resin, urethane-modified silicone resin, etc., and silicone resin as a hard coat agent can be applied. These modified silicone resins can be used alone, but SiO 2 is used for the purpose of improving durability.
A mixed material with a condensate of a metal alkoxy compound capable of forming a film containing ₂ , ₂ , TiO ₂ , In ₂ O ₃ , and ZrO ₂ as a main component is preferable. Although the film thickness of the coating layer itself depends on the composition of the coating layer, it can be arbitrarily set within a range that does not cause adverse effects such as increase in residual potential when repeatedly and continuously used.

Example 1 1 part by weight of the bisazo compound represented by the chemical formula II-1 was used as the charge generating substance, and diallylphthale was used as the binder resin.
1 part by weight of a resin (trade name DAP K: manufactured by Osaka Soda) and 150 parts by weight of methyl ethyl ketone are mixed and kneaded with a mixer for 3 hours to prepare a coating solution to prepare a coating solution for the charge generation layer. did. Next, 1 part by weight of the compound represented by the chemical formula I-1 as a charge transport material and a polycarbonate resin (trade name: Panlite L-122 as a binder resin).
5: Teijin Kasei) 1 part by weight was dissolved in 6 parts by weight of dichloromethane to prepare a coating liquid for the charge transport layer. Next, a charge generation layer (1 μm) and a charge transport layer (20 μm) were formed on a polyester terephthalate film on which aluminum was vapor deposited.
The coating liquids prepared in this order were applied to prepare a negative charging photoreceptor. Example 2 A photoconductor was prepared in the same manner as in Example 1 except that the charge transport material of Example 1 was replaced with the compound represented by the chemical formula I-2. Example 3 A photoconductor was prepared in the same manner as in Example 1, except that the charge transport material of Example 1 was changed to the compound represented by the chemical formula I-7. Example 4 A photoconductor was prepared in the same manner as in Example 1, except that the charge transport material of Example 1 was changed to the compound represented by the chemical formula I-8.

Example 5 A photoconductor was prepared in the same manner as in Example 1 except that the charge transport material of Example 1 was changed to the compound represented by the chemical formula I-16. Example 6 A photoconductor was prepared in the same manner as in Example 1 except that the charge generating substance of Example 1 was changed to the bisazo compound represented by the chemical formula III-1. Example 7 A photoconductor was prepared in the same manner as in Example 2 except that the charge generating substance of Example 2 was changed to the bisazo compound represented by the chemical formula III-1. Example 8 A photoconductor was prepared in the same manner as in Example 3 except that the charge generating substance of Example 3 was replaced with the bisazo compound represented by the chemical formula III-1. Example 9 A photoconductor was prepared in the same manner as in Example 4 except that the charge generating substance of Example 4 was replaced with the bisazo compound represented by the chemical formula III-1.

Example 10 A photoconductor was prepared in the same manner as in Example 5, except that the bisazo compound represented by the chemical formula III-1 was used instead of the charge generating substance in Example 5. Example 11 A photoconductor was prepared in the same manner as in Example 1 except that the polycyclic quinone compound represented by the chemical formula IV-4 was used instead of the charge generating substance in Example 1. Example 12 A photoconductor was prepared in the same manner as in Example 2 except that the polycyclic quinone compound represented by the chemical formula IV-4 was used instead of the charge generating substance in Example 2. Example 13 A photoconductor was prepared in the same manner as in Example 3 except that the polycyclic quinone compound represented by the chemical formula IV-4 was used instead of the charge generating substance in Example 3. Example 14 A photoconductor was prepared in the same manner as in Example 4 except that the polycyclic quinone compound represented by the chemical formula IV-4 was used instead of the charge generating substance in Example 4.

Example 15 A photoconductor was prepared in the same manner as in Example 5 except that the polycyclic quinone compound represented by the chemical formula IV-4 was used instead of the charge generating substance in Example 5. Example 16 A photoconductor was prepared in the same manner as in Example 1 except that the charge generating substance of Example 1 was changed to the squarylium compound represented by the chemical formula V-8. Example 17 A photoconductor was prepared in the same manner as in Example 2 except that the charge generating substance of Example 2 was replaced with the squarylium compound represented by the chemical formula V-8. Example 18 A photoconductor was prepared in the same manner as in Example 3 except that the charge generating substance of Example 3 was changed to the squarylium compound represented by the chemical formula V-8. Example 19 A photoconductor was prepared in the same manner as in Example 4 except that the charge generating substance of Example 4 was replaced with the squarylium compound represented by the chemical formula V-8.

Example 20 A photoconductor was prepared in the same manner as in Example 5 except that the charge generating substance of Example 5 was changed to the squarylium compound represented by the chemical formula V-8. Example 21 A photoconductor was prepared in the same manner as in Example 1 except that the charge generating substance in Example 1 was changed to metal-free phthalocyanine. Example 22 A photoconductor was prepared in the same manner as in Example 2 except that the charge generating substance in Example 2 was changed to metal-free phthalocyanine. Example 23 A photoconductor was prepared in the same manner as in Example 3 except that the charge generating substance in Example 3 was changed to metal-free phthalocyanine. Example 24 A photoconductor was prepared in the same manner as in Example 4 except that the charge generating substance in Example 4 was changed to metal-free phthalocyanine. Example 25 A photoconductor was prepared in the same manner as in Example 5 except that the charge generating substance in Example 5 was changed to metal-free phthalocyanine.

Comparative Example 1 The same as in Example 1 except that the charge transport material of Example 1 was changed to 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2-pyrazoline (ASPP). A photoconductor was created. Comparative Example 2 A photoconductor was prepared in the same manner as in Example 1 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 1. Comparative Example 3 A photoconductor was prepared in the same manner as in Comparative Example 1 except that the charge generating substance of Comparative Example 1 was changed to ε-type copper phthalocyanine. Comparative Example 4 A photoconductor was prepared in the same manner as in Comparative Example 3 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Comparative Example 3.

Electrophotography of the photoconductor thus obtained
Characteristics of electrostatic recording paper testing device "SP-428" manufactured by Kawaguchi Denki
Was measured. Surface potential V of photoreceptor_S(Bolt) is
Exposure to -6.0 kV corona discharge for 10 seconds in the dark
It is the initial surface potential when the body surface is negatively charged,
Subsequently, the corona discharge was stopped and the sample was kept in the dark for 2 seconds.
Surface potential V_D(Volt) is measured, and then
The surface of the photoconductor is irradiated with white light with an illuminance of 2 lx to V_DBut
Half-exposure exposure E_1/2
(Lx · s). Also, 2 lx white light for 10 seconds
The surface potential when the surface of the photoconductor is irradiated with the residual potential V _r
(Bolt). The results are shown in Table 3.

[0039]

[Table 3]

As can be seen from Table 3, the surface potentials of Examples 1 to 25 are equivalent to those of Comparative Examples 1 to 4, but the residual potential and the half-attenuated exposure amount are clearly improved. It is clear that the combination of the thiophene derivative with various charge generating substances is superior.

[0041]

According to the present invention, the compound represented by the general formula [I] is used as the charge transport substance, and the compound represented by the general formula [II] to [V] or the metal-free phthalocyanine is used as the charge generation substance. Alternatively, by using titanyl phthalocyanine, a high-sensitivity and excellent repeating property can be obtained as an electrophotographic photoreceptor for a copying machine.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a negative charging type electrophotographic photoconductor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a positive charging type electrophotographic photoconductor according to an embodiment of the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Charge Generation Layer 3 Charge Transport Layer 4 Photosensitive Layer 5 Surface Covering Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G03G 5/06 384 8305-2H (72) Inventor Kenichi Okura 1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 in Fuji Electric Co., Ltd. (72) Inventor Noboru Furusho No. 1 Nitta Tanabe, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd.

Claims (11)

[Claims] 1. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer comprises a thiophene derivative represented by the general formula [I] as a charge transport substance and a bisazo compound represented by the general formula [II] as a charge generation substance. A photoreceptor for electrophotography, characterized in that it contains. [Chemical 1] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.) (R ₇ represents a halogen atom, an alkyl group or an alkoxy group, R ₈ represents an optionally substituted alkyl group, R ₉ represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxyl group, an ester group or an acyl group. , R ₁₀ represents a hydrogen atom, a halogen atom, a nitro group or an optionally substituted alkyl group or an alkoxy group.) 2. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer comprises a thiophene derivative represented by the general formula [I] as a charge transporting substance and a bisazo compound represented by the general formula [III] as a charge generating substance. A photoreceptor for electrophotography, characterized in that it contains. [Chemical 3] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Represents an alkyl group, and n represents an integer of 1 to 3.) (R ₁₁ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group or an alkoxy group, R ₁₂ represents an optionally substituted alkyl group, an aryl group or an aromatic heterocyclic group, and R ₁₃ Is a hydrogen atom, a cyano group,
It represents a carbamoyl group, a carboxyl group, an ester group or an acyl group, and R ₁₄ and R ₁₅ each represent a hydrogen atom, a halogen atom, a nitro group or an optionally substituted alkyl group or alkoxy group. ) 3. A photosensitive layer on a conductive substrate, the photosensitive layer comprising a thiophene derivative represented by the general formula [I] as a charge transporting substance and a polycyclic quinone compound represented by the general formula [IV] as a charge generating substance. A photoreceptor for electrophotography, comprising: [Chemical 5] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.) (X represents a hydrogen atom, a halogen atom, or a cyano group, and m represents an integer of 0 to 4.) 4. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer comprises a thiophene derivative represented by the general formula [I] as a charge transport substance and a squarylium compound represented by the general formula [V] as a charge generation substance. A photoreceptor for electrophotography, characterized in that it contains. [Chemical 7] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n is an integer of 1 to 3.) (R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ are each an optionally substituted alkyl group, aryl group, aralkyl group, or alkenyl group, and R ₁₆ and R ₁₇ , or R ₁₈ and R ₁₉ may form a ring. Well, R
₂₀ and R ₂₁ are a hydrogen atom, a halogen atom, a hydroxy group,
Represents an alkyl group and an alkoxy group. ) 5. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer contains a thiophene derivative represented by the general formula [I] as a charge transporting substance and a metal-free phthalocyanine or titanyl phthalocyanine as a charge generating substance. A photoconductor for electrophotography. [Chemical 9] (R ₁ and R ₂ represent a hydrogen atom, an alkyl group or an aryl group, and R ₃ , R ₄ , R ₅ and R ₆ are a hydrogen atom, an alkoxy group or an optionally substituted alkyl group or aryl group. Group, and n represents an integer of 1 to 3.) 6. The electrophotographic photoreceptor according to claim 1, 2, 3, 4 or 5, wherein the photosensitive layer comprises two layers of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. An electrophotographic photoconductor characterized by the following. 7. The photoconductor for electrophotography according to claim 1.
The thiophene derivative represented by the general formula [I] is R_1,
R₂Is a hydrogen atom, R_3,R_Four,R_FiveIs C₆H_FiveBase, n is 1
The bisazo compound represented by the general formula [II] is represented by R₇
Is Cl atom, R ₈Is CH₃Group, R₉Is a CN group, R_TenBut water
A photoreceptor for electrophotography, which is an elementary atom. 8. The electrophotographic photoreceptor according to claim 2, wherein the thiophene derivative represented by the general formula [I] is R _1,
R ₂ is a hydrogen atom, R _3, R _4, R ₅ are C ₆ H ₅ groups, n is 1, and the bisazo compound represented by the general formula [III] is R
_11, R _14, R ₁₅ are hydrogen atoms, R ₁₂ is a CH ₃ group, and R ₁₃ is C
An electrophotographic photoreceptor, which is an N group. 9. The electrophotographic photoreceptor according to claim 3, wherein the thiophene derivative represented by the general formula [I] is R _1,
R ₂ is a hydrogen atom, R _3, R _4, R ₅ are C ₆ H ₅ groups, n is 1, and the polycyclic quinone compound represented by the general formula [IV] is
Is a bromine atom, and m is 2. An electrophotographic photoreceptor. 10. The electrophotographic photoreceptor according to claim 4, wherein the thiophene derivative represented by the general formula [I] is R _1,
R ₂ is a hydrogen atom, R _3, R _{4 and} R ₅ are C ₆ H ₅ groups, n is 1, and the squarylium compound represented by the general formula [V] is R ₁₆ , R _17, R ₁₈ and R ₁₉ CH ₃ group, R _20, R ₂₁ are OH
An electrophotographic photoreceptor, which is a base. 11. The electrophotographic photoreceptor according to claim 5, wherein the thiophene derivative represented by the general formula [I] is R _1,
A photoreceptor for electrophotography, wherein R ₂ is a hydrogen atom, R _3, R _{4 and} R ₅ are C ₆ H ₅ groups, and n is 1.