JPS63208852A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a sensitive body causing no rise of residual potential and having stable electrical characteristics by incorporating a specified azo pigment into an intermediate layer on an electrically conductive substrate. CONSTITUTION:This electrophotographic sensitive body contains at least one kind of azo pigment represented by formula I in the intermediate layer. In the formula, X is an arom. ring such as benzene or naphthalene, a hetero ring such as indole, carbazole or benzofuran, or a substituted product thereof, Ar1 is an arom. ring such as benzene or naphthalene, a hetero ring such as dibenzofuran or a substituted product thereof, each of Ar2 and Ar3 is an arom. ring such as benzene or naphthalene or a substituted product thereof, each of R1 and R3 is H atom, lower alkyl, phenyl group or a substituted product thereof and R2 is lower alkyl, carboxyl group or ester thereof. The sensitive body causes no rise of residual potential, has stable electrical characteristics independently of a change in environmental conditions such as temp. and humidity and gives a copied image of high reliability without forming a spotted abnormal image or causing ground stain.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an improvement in an electrophotographic photoreceptor in which an intermediate layer, a charge generation layer, and a charge transfer layer are successively laminated on a conductive substrate.

[Prior art]

A photoreceptor formed from a charge generation layer and a charge transfer layer is provided on a conductive substrate, and then the photoreceptor is uniformly charged with a corona and a charger and exposed for one image to form an electrostatic latent image corresponding to optical information. When a toner is formed on the surface of a photoreceptor and then developed with a developer containing charged colored particles (toner), a spot-like abnormal image is generated. When the charge polarity of the toner is opposite to the charge polarity of the photoreceptor (regular development), the toner adhering part of the image (in the case of black-and-white development, the part corresponding to the so-called solid black part)
When the toner charge polarity is the same as the charge polarity (reversal development), patchy white spots (referred to as white spots) of several mm to 0.1 mm in size occur on the image. A spot-like abnormal image of about 0.1 to several 111 meters in size (a portion corresponding to the background), so-called background dirt, occurs.

These spot-like abnormal images occur when the image forming process of charging, exposing, developing, and transferring the photoreceptor is repeated.

As the imaging process is repeated, spots tend to become denser and larger in size. Furthermore, depending on the photoreceptor, the problem may occur from the beginning of image formation.

This spotty abnormal image is from an electrophotographic copying machine.

This will significantly impair the copy quality and print quality of printers and facsimile machines.

This abnormal image occurs because when the photoreceptor is charged with a corona or charger, charges are locally injected from the chargeable substrate into the photosensitive layer, resulting in the existence of local low potential areas on the surface of the photosensitive layer, which prevents development. This is based on the fact that non-uniformity occurs. Therefore, it has been proposed to provide an intermediate layer between the conductive layer and the charge generation layer for the purpose of preventing charge injection.

For example, JP-A Nos. 47-6341, 48-3544 and 48-12034 have cellulose sulfate resin intermediate layers; No. 58-9
No. 5351, No. 58-98739 and No. 60-6625
No. 8 has a nylon resin intermediate layer, as disclosed in Japanese Patent Application Laid-open No. 48-261.
No. 41 has a vinyl acetate resin intermediate layer, as disclosed in JP-A-49-6.
No. 9332 and No. 52-10138 disclose a maleic acid resin intermediate layer, and JP-A-58-103155 discloses a polyvinyl alcohol resin intermediate layer.

A photoreceptor using such an intermediate layer has fewer abnormal images in the form of a single spot than a photoreceptor without an intermediate layer, and the intermediate layer is effective. However, the intermediate layer reduces the sensitivity of the photoreceptor, and as the image forming process is repeated, the residual potential gradually increases. In addition, the resin intermediate layer is easily affected by moisture in the air, and the residual potential becomes particularly high at low temperatures and low humidity. There was a problem in that it caused dirt.

〔the purpose〕

The present invention provides an electrophotographic photoreceptor that does not have an increase in residual potential, exhibits stable electrical characteristics even when the environment such as temperature and humidity fluctuates, and does not cause spot-like abnormal images or background stains. The purpose is to

〔composition〕

According to the present invention, in an electrophotographic photoreceptor in which an intermediate layer, a charge generation layer, and a charge transfer layer are sequentially laminated on a conductive substrate, the intermediate layer is an azo pigment represented by the following general formula (1'). Provided is an electrophotographic photoreceptor comprising a thermosetting resin containing at least one of the following.

(However, in formula (1), A is a group represented by X, Ar1, Ar, , Ar
s, R,.

R*, R, are as follows.

X: aromatic ring such as a bemain ring or a naphthalene ring.

Heterocycles with indole rings, carbazole rings, benzofuran rings, or substituted products thereof.

Ar1; aromatic ring such as a benzene ring or naphthalene ring, a hetero ring such as dibenzofuran, or a substituted product thereof.

Ar, , Ar, ; Aromatic ring such as a benzene ring or naphthalene ring, or a substituted product thereof; R□, R1; Hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof.

R2; lower alkyl group, carboxyl group, or ester thereof) The present inventors have developed a photoreceptor for electrophotography that can suppress the occurrence of spotty abnormal images by increasing the charging property, and can also reduce the residual potential and prevent background smearing. As a result of intensive studies, we found that when a thermosetting resin containing at least one azo pigment represented by the above general formula (1) is used as the intermediate layer, an electrophotographic photoreceptor suitable for the above purpose can be obtained. Find out what you can get,
The present invention has now been completed.

In conventional electrophotographic photoreceptors, by increasing the thickness of the intermediate layer, charging performance can be increased and the formation of spot-like abnormal images can be suppressed, but due to repeated charging and exposure, the residual potential increases significantly. .

Dirt appears on the skin. On the other hand, if the thickness of the intermediate layer is made thinner, it is possible to suppress the increase in the residual potential, but in this case, the charging property decreases and a spot-like abnormal image occurs. No material has been found that simultaneously satisfies these two characteristics.

In addition, the conventional photoreceptor has the drawback that the residual potential increases significantly under low temperature and low humidity conditions, and the photoreceptor characteristics fluctuate due to environmental changes.However, the electrophotographic photoreceptor according to the present invention As shown, even if the environment changes, it is possible to provide a good copy image without spotty white spots or background stains.

The present invention will be explained in more detail below.

The electrophotographic photoreceptor according to the present invention is formed by sequentially laminating an intermediate layer, a charge generation layer, and a charge transfer layer on a conductive substrate.

The conductive substrate is intended to supply charges of opposite polarity to the charged charges to the substrate side, and has an electrical resistance of 10
10c11 or less and that can withstand the film forming conditions of the intermediate layer, charge generation and charge transfer layer can be used. Examples of these are AΩ, Ni, Cr, Zn
, vacuum evaporation, sputtering, spray painting, etc. on the surfaces of electrically conductive metals and alloys such as stainless steel, inorganic insulating materials such as glass and ceramics, and organic insulating materials such as polyester, polyimide, phenol resin, and nylon resin paper. By the method of AQ, Ni%Cr%Zn
, stainless steel, carbon, 5n4), In, O, etc., coated with an electrically conductive material and subjected to conductive treatment.

The intermediate layer may contain a disazo pigment represented by the above general formula (R) in a dispersed state in a binder resin. Examples of the binder resin include polyester resin, polystyrene resin, polycarbonate resin, polyacrylate resin, and polyvinyl butyral resin. Thermoplastic resins such as polyvinyl acetate resin, ethyl cellulose resin, polysulfone resin, and polyvinyl carbazole resin can be used, but when overcoating the charge generation layer and charge transport layer on the intermediate layer, the intermediate layer may melt. Therefore, it is more preferable to use a thermosetting resin as shown below as the binder resin.

The thermosetting resin has, for example, active hydrogen (-〇H group, -N1
It is obtained by thermally polymerizing a compound containing a plurality of hydrogen groups such as 1° group and -NH group, and a compound containing a plurality of isocyanate groups and/or a compound containing a plurality of epoxy groups. Examples of compounds containing multiple active hydrogens include polyvinyl butyral, phenoxy resins, phenol resins, polyamides, acrylic resins containing active hydrogen such as hydroxyethyl methacrylate groups, and compounds containing multiple isocyanate groups. Examples of the compound include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and prepolymers thereof, and examples of compounds containing a plurality of epoxy groups include bisphenol A type epoxy resin.

In the present invention, the bisazo pigment represented by the general formula (I) is used, and its content is from 3 parts by weight to 100 parts by weight, preferably 5 parts by weight, based on 10 parts by weight of the resin.
It is 50 heavy water metropolis from the weight part.

Dispersion methods for disazo pigments in resin include ball mill,
Ultrasonic methods, three rolls, sand gliders, attritors, impellers, stone mills, etc. can be used.

To disperse a disazo pigment in a thermoplastic resin, it is sufficient to add the pigment to an organic solvent solution of the resin and disperse it by grinding and mixing using the above dispersion means. However, when dispersing it in a thermosetting resin, first disazo After the pigment is dispersed in an organic solvent solution of a compound containing active hydrogen, a compound containing a plurality of isocyanate groups and/or a compound containing a plurality of epoxy resins is added. This is to avoid thermal polymerization in the dispersion step, since the dispersion step involves heat generation. The intermediate layer is formed on the conductive substrate by a conventionally known coating method such as roll coating, dip coating, spray coating, or blade coating, followed by heating at 50°C to 200°C. Polymerize to a film thickness of 0.1μ
The intermediate layer has a diameter of 0.5 μm to 10 μm (preferably 0.5 μm to 5 μm).

Next, specific examples of the compound represented by the general formula (1) used in the present invention are shown below.

The charge generation layer is a layer whose purpose is to generate and separate charges by image exposure. In the present invention, the charge generation layer uses an organic dye/pigment, crystalline selenium, or arsenic selenide as a charge generation substance. Examples of organic pigments include phthalocyanine pigments, disazo pigments, trisazo pigments, perylene pigments, squalic basic dyes, azulenium salt dyes, and quinone condensed polycyclic compounds. Specific examples of disazo pigments and trisazo pigments are shown below.

1 and L -Each person is 111 and long -Koshi -One face JL limb -1 δ --- almu!
2 - 11 to 11 face J [corner
−1−Δ−−−Face” L outfit −
118--1In1Lh -1 person 111 oxh -1 piece m- 1 and Jkl --JL-1 face 4L
−−−Δ−−−Face 4 [Fire
-11Δ-1-ILMk-8=1and-NQ-1Coshy-1NU.

Group J [Correct -1-Δ---Face 41 Intuition --Kom Face J Rainbow Nu
-11 to 111 JLNQ-
118111 Tsuzuru J [Yang -i face] L dying -1-to---1 hill length
-1' L-1 Face JL & -11---These organic dyes and pigments are ball-milled or sand-milled in a resin or without a resin by adding an organic solvent.

It is used after being dispersed by methods such as triple roll, attritor, and ultrasonic methods. Examples of the resin for dispersing these organic dyes and pigments include polyamide, polyurethane, polyester, epoxy resin, and polycarbonate.

Examples include condensation resins such as polyether, and polymers and copolymers such as polystyrene, polyacrylate, polymethacrylate, boso N-vinylcarbazole, polyvinyl butyral, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, Insulation and adhesive properties are required. Disperse using the same dispersion means as above, form a film on the intermediate layer using the same method as the intermediate layer, and dry it to a film thickness of 0.
, 05 μI to several μm in thickness. The content of the organic dye and pigment is preferably 60% by weight and 100% by weight.

The purpose of the charge transfer layer provided on the charge generation layer is to retain the charged charges on its surface, and also to move the charges generated and separated in the charge generation layer by exposure and combine them with the held charges. This is the layer where In order to achieve the purpose of retaining electrical charges, high electrical resistance is required.
In addition, in order to achieve the purpose of obtaining a high surface potential using the retained charges, it is required that the dielectric constant be small and the charge mobility be good. In order to satisfy these requirements, an organic charge transfer layer containing an organic charge transfer substance as an active ingredient is used. Examples of organic charge transfer substances include:
Poly-N-vinylcarbazole compounds, pyrazoline compounds, α-phenylstyrene bene compounds, hydrazone compounds, diarylmethane compounds, triphenylamine compounds, divinylbenzene compounds, fluorine compounds, anthracene compounds, Conventionally known compounds such as oxadiazole compounds and diaminocarbazole compounds can be used.

These organic charge transfer substances other than polymers such as polyvinylcarbazole are used by being blended with the same resin as shown as the binder for the charge generation layer described above. However, it is not necessary that the resin used in the charge generation layer and the resin used in the charge transfer layer be the same, and a plasticizer may be added to them if necessary. Examples of such plasticizers include halogenated paraffins, dimethylnaphthalene, dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, and copolymers of polymers such as polyester. A charge transfer substance, the binder resin, and silicone oil (as a leveling agent during film formation) are dissolved in an organic solvent, and a film is formed and dried in the same manner as the intermediate layer and charge generation layer to form a patterned film. A charge transport layer of 5 μl to 100 μl is formed on the charge generation layer. The charge transfer material to resin binder ratio is from 2/8 to 872 weight ratios, and the amount of silicone oil to resin binder is from 0.001 parts by weight to 1 part by weight.

〔effect〕

Since the electrophotographic photoreceptor of the present invention uses a thermosetting resin containing at least one azo pigment represented by the general formula (I) as the intermediate layer, there is no increase in residual potential;
Moreover, it exhibits stable electrical characteristics even when the environment such as temperature and humidity changes, and provides highly reliable copied images that do not generate one-spot abnormal images or background stains.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A glass pot of 12c+aφ is filled with 10
An alumina sintered ball of mmφ was put therein, and 120 g of the following resin liquid A, an azo pigment of o, sg/ (azo pigment No. (1)-1 for intermediate layer) and 100 g of methyl ethyl ketone were added and mixed for 72 hours. After 220 g of methyl ethyl ketone was added and mixed for 24 hours, 27 g of the following TDI solution and 240 g of methyl ethyl ketone were added to 420 g of this dispersion to prepare an intermediate layer coating solution.

[Resin liquid A]

Cyclohexanone 92 stacked parts (TD
Solution I] Tolylene diisocyanate 10 parts by weight Methyl ethyl ketone 90 parts by weight Next, φ15
25 g of cyclohexanone and 400 g of cyclohexanone with a stainless steel pole of 172 mm volume in a cm glass pot.
48 by adding azo pigment (Not) for charge generation material.
Mixed for an hour.

After adding an additional 408 g of cyclohexanone and mixing for another 24 hours, 800 g of the dispersion solution was taken out.
While stirring, 800 g of tetrahydrofuran was added dropwise to obtain a charge generation layer coating solution.

The above intermediate layer coating solution was applied by dip coating onto an aluminum drum with a wall thickness of 2 mm, 80 φ x 340 m+*, and then heated and cured at 130° C. for 1 hour to form an intermediate layer with a thickness of 2 μm. The aluminum drum on which the intermediate layer was formed was immersed in the above charge generation layer coating solution at 2°C, pulled up at a speed of 15 mm for 1 second to perform dip coating, and then dried at 130°C for 10 minutes to form a charge generation layer. Further, a charge transfer layer coating solution shown below was applied thereon by dip coating and dried at 130° C. for 1 hour to form a charge transfer layer of 20 μm thick.

[Charge transfer layer coating liquid (composed of the following composition)] α-
Phenylstilbene-based charge transfer substance Compound below) Tetrahydrofuran 80 parts by weight The photoreceptor drum thus prepared was treated with FT4060 (i
When the image was evaluated using a developer for FT8030 (a Ricoh copying machine), a clear image was obtained with no spots in the solid black area.

Further, the photoreceptor was subjected to forced fatigue by repeating only exposure and charging 1000 times, and then developed and image evaluation revealed that an image was obtained without any spots or stains on the background.

In addition, this photoreceptor was subjected to initial image, charging and exposure cycles 1000 times in the same manner as above in an environment of 10° C. and 15% RH.
When the images after the test were evaluated, it was found that there were no spotty spots or stains on the skin.

Comparative Example 1 The charge generation layer and charge transfer layer liquid shown in Example 1 were coated in the same manner as in Example 1 without providing an intermediate layer on an aluminum drum having a wall thickness of 2s+n, a length of 80φ and a length of 340mm.

A photoreceptor was created.

Comparative Example 2 A photoreceptor was prepared in the same manner as in Example 1, except that the following resin liquid B was used instead of the intermediate layer in Example 1 and was dip coated and cured by heating at 130° C. for 1 hour to form an intermediate layer of 2μ. It was created.

[Resin liquid B]

Tolylene diisocyanate (TDI) 14.5 parts by weight Cyclohexane 552 parts by weight Methyl ethyl ketone 130 parts by weight Mizuto Example 2 The azo pigment for the intermediate layer of Example 1 was exemplified in Table 1. A photoreceptor was produced in the same manner as in Example 1, except that Example 1)-2 was used.

Example 3 A photoreceptor was produced in the same manner as in Example 1, except that the azo pigment for intermediate layer No. (1)-5 exemplified in Table 1 was used as the azo pigment for intermediate layer of Example 1.

Example 4 A photoreceptor was produced in the same manner as in Example 1, except that the azo pigment for intermediate layer No. (1)-13 exemplified in Table 1 was used as the azo pigment for intermediate layer of Example 1.

Example 5 The same intermediate layer coating solution as in Example 1 was dip-coated on an aluminum drum with a wall thickness of 211 m and 1.80 φ x 340, and
It was cured by heating at 130° C. for 1 hour to form an intermediate layer with a thickness of 2 μm.

Also, add 1/2 of the volume to a glass pot with a diameter of 15 cm.
Add 400 g of resin liquid C below and 25 g of azo pigment (No. 39) for charge-generating material.
was added and mixed for 48 hours. Furthermore, 580g of resin liquid C
was added and mixed for a further 24 hours, and then 710 g of methyl ethyl ketone was added dropwise to 950 g of the dispersion solution taken out while stirring to obtain a charge generation layer coating solution.

The aluminum drum provided with the intermediate layer described above was immersed in this charge generation layer coating solution, pulled up at a speed of 6 mm/sec for coating, and then heated and dried at 130° C. for 10 minutes to form a charge generation layer.

Next, the charge transfer layer coating solution shown in Example 1 was applied by dip coating in the same manner as in Example 1, and a charge transfer layer having a thickness of 20 μm was provided to prepare a photoreceptor.

[Resin liquid C]

Cyclohexane 970 parts by weight Example 6 Example 5 except that the intermediate layer azo pigment No. (1)-21 exemplified in Table 1 was used instead of the intermediate layer azo pigment of Example 5.
A photoreceptor similar to that was created.

Comparative Example 3 A photoreceptor was prepared in the same manner as in Example 5, except that instead of the intermediate layer in Example 5, the following resin solution (D) was applied and heated at 130° C. for 10 minutes to form an intermediate layer with a thickness of 2 μm. Created.

[Resin liquid D]

Nylon resin (manufactured by Toshisha) 8 parts by weight methanol 60 parts by weight butanol
32 Jusha Department The photoconductor thus prepared was tested at room temperature (22°C to 25°C, 50% R11 to 65%) using the modified copying test apparatus shown in Example 1.
Image evaluation was performed in the same manner as in Example 1 under a low temperature, low humidity (10° C., 15% RH) environment.

The results are shown in Tables 2 and 3. It can be seen that the photoreceptor of the present invention provides stable copied images free from spotty white spots and background smudges, despite environmental changes.

The meaning of each symbol in the table is as follows.

0: Abnormal image does not occur Δ: Abnormal image occurs, but the degree is slight and there is no substantial problem. %
Procedural amendment V (spontaneous) June 1, 1988 Director General of the Patent Office Kunio Ogawa 1, Indication of the case 1988 Patent Application No. 43602 2, Name of the invention Photoreceptor for electrophotography 3, Person making the amendment Case Relationship with Patent Applicant Address 1-3-6 Nakamagome, Ota-ku, Tokyo Name Name
(674) Rico Co., Ltd. - Representative Hama 1
) Hiro 4, Agent 151 Address 1-58-10 Yoyogi, Shibuya-ku, Tokyo Column 8 of "Claims" and "Detailed Description of the Invention" of the specification, Contents of amendments in the specification of the present application , make the following corrections.

(1) The scope of patent claims will be corrected as shown in the attached sheet.

(2) On page 2, line 19, "a photoreceptor is provided, and then on the photoreceptor" is corrected to "on the photoreceptor with a photosensitive layer provided". (3) on page 2, line 19 - Correct "Corona, Charger" in line 20 to "Corona Charger."

(4) Correct "charged" in the second line of page 3 to "charged".

(5) "Sakaku~0.1m" on page 3, line 7, by ro
, 1■ to several ■".

(6) Change “Corona, Charger” in the first line of page 4 to “
Corrected to ``Corona Charger.''

(7) Correct "cellulose sulfate" in line 4 and line 9 to "cellulose nitrate."

(8) Page 4, line 15, “Unexamined Japanese Patent Publication No. 58-103155J
I am correcting ``Unexamined Japanese Patent Publication No. 58-105155J.

(9) In page 5, line 15, “the middle class” was changed to “to the middle class”.
I will correct it.

(10) On page 5, lines 16 to 17, "characterized by being made of a thermosetting resin containing at least one kind of azo pigment" is replaced with "made of a thermosetting resin containing at least one kind of azo pigment." It has been corrected to "characterized by".

(11) In line 6 of page 7, "as a middle class" is corrected to "to a middle class."

(12) Delete “Using thermosetting resin” from lines 7 to 8 of page 7.

(13) Correct "conductive substrate" in line 8 of page 8 to "conductive substrate."

(14) Correct “and” in line 18 of page 8 to “and”.

(15) The structural formula of pigment No. (1)-18 on page 14 is corrected as follows.

(16) Change “Mimetic film 5μm” in the second line of page 40 to “Film thickness 5μm”.
I'll correct it to "μugly".

(17) In line 7 of page 40, "as a middle class" is corrected to "to a middle class."

(18) Delete “Using thermosetting resin” on page 40, line 9.

(19) RO, 5g/azo pigment” at the end of page 40,
Corrected to ``rlo, 5g of azo pigment''.

(20) Page 41, line 5, “Add / to old,” “Add to”
I will correct it.

(21) In the 8th line from the bottom of page 44, [cyclohexane] will be corrected to "cyclohexanone."

(22) [Cyclohexane] in line 12 from the bottom of page 46
will be corrected to "cyclohexanone".

(23) r Nylon resin (manufactured by Toshisha Co., Ltd.) at the end of page 46”
will be corrected to "Nylon resin (CM-8000 manufactured by Toshisha) J.

(24) "Substantially" in lines 13 and 14 of page 47 is corrected to "substantially."

``Claims (1) An electrophotographic photoreceptor comprising an intermediate layer, a charge generation layer, and a charge transfer layer sequentially laminated on a conductive substrate.

An electrophotographic photoreceptor characterized in that the intermediate layer contains at least one azo pigment represented by the following general formula ([).

A group represented by X, Ar1. Ar,, Ar
,, R,,R, are as follows.

X: A heterocycle with an aromatic ring such as a benzene ring or a naphthalene ring, an indole ring, a carbazole ring, or a benzofuran ring, or a substituted product thereof.

Ar, aromatic ring such as benzene ring or naphthalene ring, hetero ring such as dibenzofuran or substituted product thereof, Ar,
l^r3; Aromatic ring such as a benzene ring or naphthalene ring, or a substituted product thereof; Rx+Ra; Hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof.

R2; lower alkyl group, carboxyl group or ester thereof)” Procedural amendment (voluntary) May 18, 1988 Director General of the Patent Office Kunio Ogawa 1, Indication of case 1988 Patent Application No. 43602 2, Invention Name of photoreceptor for electrophotography 3, Relationship to the case of the person making the amendment Patent applicant address 1-3-6 Nakamagome, Ota-ku, Tokyo Name Name
(674) Rico Co., Ltd. - Representative Hama 1
) Hiro 4, Agent 151 Address 1-58-10-5 Yoyogi, Shibuya-ku, Tokyo
Date of amendment order Voluntary 6, Number of inventions increased by amendment O8, Contents of amendment The following amendments will be made to the specification of the application.

(1) The structural formula of pigment No. 1, (1)-9 on page 13 is corrected as follows.

"

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which an intermediate layer, a charge generation layer, and a charge transfer layer are sequentially laminated on a conductive substrate, the intermediate layer contains at least one azo pigment represented by the following general formula (I). An electrophotographic photoreceptor comprising a thermosetting resin containing seeds. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (However, in formula (I), A is a group represented by ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and X, Ar_1, Ar_2, A
r_3, R_1, R_2, and R_3 are as follows. X; an aromatic ring such as a benzene ring or a naphthalene ring, a hetero ring such as an indole ring, a carbazole ring, or a benzofuran ring, or a substituted product thereof. Ar_1; Aromatic ring such as benzene ring or naphthalene ring, hetero ring such as dibenzofuran, or substituted product thereof; Ar_2, Ar_3; Aromatic ring such as benzene ring or naphthalene ring, or substituted product thereof; R_1, R_3; Hydrogen, lower alkyl group, phenyl group or a substituted product thereof, R_2; lower alkyl group, carboxyl group or ester thereof)