JPH08160643A - Coating material for charge generating layer, electrophotographic photoreceptor with it, and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide an electrophotographic photoreceptor having high sensitivity for the long-wavelength light such as semiconductor laser in particularly, having few image defects and few black spots at the time of reversal processing, generating no fog-like black spot in the high-temperature and high-humidity environment and the potential reduction during the repetitive use, and having a high gradation and excellent resolution by combining a specific charge generating material and a binder resin. CONSTITUTION: α-type titanyl phthalocyanine, which is a crystal showing strong diffraction peaks at the Bragg angles (2θ±0.2 deg.) of 7.6 deg., 10.3 deg., 12,7 deg., 16,3 deg., 22.7 deg., 24.3 deg., 25.5 deg., and 28.6 deg. in the X-ray diffraction spectrum, a polyvinyl butyral resin, and an i-butylmelamine resin are dispersed in a solvent to form a coating material for a charge generating layer 4. This coating material is used to form the charge generation layer 4 on a conducting base 2 by the dip coating method, and thermosetting is applied after coating. A coating material for a charge transfer layer 5 is dip coated on the charge generating layer 4 to form the charge transfer layer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge generation layer coating material used in the production of an electrophotographic photoreceptor, an electrophotographic photoreceptor obtained by using the same, and a method for producing the photoreceptor, more specifically, with high sensitivity. The present invention relates to an improved electrophotographic photoreceptor that is stable against repetition.

[0002]

2. Description of the Related Art In recent years, an organic photoconductor containing an organic photoconductive substance has been developed and put into practical use as an electrophotographic photoconductor because of its advantages such as easy film formation, inexpensiveness and no pollution. In particular, the development of organic photoconductors having a high sensitivity in the long wavelength region, which are suitable for optical printers such as laser beam printers using a semiconductor laser as a light source, and facsimiles is remarkable. Most of the practically used organic photoconductors are laminated organic photoconductors in which a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance are laminated, and a functional separation structure is provided. As a result, the degree of freedom in selecting materials has been further expanded, and the electrophotographic characteristics such as charging property, sensitivity and durability have been greatly improved.

On the other hand, in the copying industry, high image quality and image editing function are demanded, and therefore, development of digital type copying machines and printers is promoted, and particularly, market expansion of laser beam printers, plain paper facsimiles, etc. It has been planned. Therefore, it is desired to improve the characteristics of the photoconductor suitable for those digital recording devices. The digital recording apparatus generally forms a dot latent image on a photoconductor by performing dotwise exposure with laser light modulated by an image signal, and reverse-developing the latent image to form an image. At this time, as the laser light, a semiconductor laser device capable of simplifying the exposure apparatus, downsizing, and cost reduction is preferably used,
Its oscillation wavelength is in the infrared region above 750 nm. Therefore, as the photoconductor used, at least 750 to 850
It is required to have high sensitivity in the wavelength region of nm.

By the way, various organic dyes or organic pigments have been proposed as the charge-generating substance used in the function-separated type photoreceptor. For example, polycyclic quinone pigments, pyrylium dyes, eutectic complexes of pyrylium dyes and polycarbonates, squarylium pigments, phthalocyanine pigments,
Azo pigments and the like have been put to practical use. Of these, 750 nm
The titanyl phthalocyanine pigment has a main sensitivity in the above long wavelength region. This titanyl phthalocyanine pigment is capable of achieving high sensitivity particularly in the long wavelength region by having a specific aggregation structure or crystal structure, and various crystal types have been proposed as its crystal type. ing.

For example, JP-A-59-4544, JP-A-59-166959 and JP-A-61-2392.
48, JP-A-62-67094, JP-A-6
2-275272, JP-A-63-366,
JP-A-63-198067 and JP-A-1-1706
No. 6, JP-A-2-267563, JP-A-3-
Japanese Patent No. 54264 discloses various crystal forms, and various titanyl phthalocyanine pigments have been studied.

[0006]

However, since many crystalline forms of titanyl phthalocyanine are unstable, they satisfy all properties such as charging ability, sensitivity, and repetitive property, and further, in terms of sensitivity, they are much higher. Sensitive ones are desired. In particular, α-type titanyl phthalocyanine is 750 nm
Although the crystal form is highly sensitive and stable as described above, as a result of our investigation, the following problems have occurred.

First, the α-type titanyl phthalocyanine pigment has poor dispersion stability as a paint because the pigment particles have a very small particle size, and depending on the binder resin and solvent used in the paint, pigment agglomeration and sedimentation may occur. This causes coating defects such as unevenness during coating and pigment aggregation, which leads to deterioration of characteristics such as sensitivity deterioration and image defects.

Secondly, in the photoconductor using α-type titanyl phthalocyanine in the charge generation layer, minute black spots were generated during reversal development, which sometimes caused image defects. In a normal electrophotographic photoreceptor, the electrical contact between the installed conductive layer and the photosensitive layer is not microscopically uniform, for example, because carrier injection from the conductive layer side differs depending on the location, A local difference occurs in the charge distribution retained on the surface of the photoconductor. This is revealed as an image defect after development,
In the positive development method, black dots are white dots, and in the negative reversal development method, white dots are black dots. In particular, the black dots in the reversal development method significantly impair the image quality like the background fog. This problem is likely to occur when the highly sensitive α-type titanyl phthalocyanine pigment is used, and the black spots are remarkable in the reversal development method. In particular, in a high temperature and high humidity environment, carrier injection is increased due to the influence of humidity, so innumerable minute black spots are generated like background fog and the image quality is remarkably deteriorated.

Regarding the first problem, as a result of various studies, it is preferable to use a polyvinyl butyral resin as the binder resin, and it is possible to improve the dispersion stability of the coating liquid, but the polyvinyl butyral resin has a hygroscopic property. As a result, the second problem was the remarkable occurrence of fog-like black spots in a high temperature and high humidity environment.

On the other hand, the second problem can be solved by using a thermosetting resin as the binder resin of the charge generation layer so as to have high moisture resistance. However, thermosetting resins such as epoxy resin, acrylic resin, and urea are used. With resins and polyester resins, the first problem is that the dispersion stability of the pigment in the paint is very poor, and it has been difficult to solve these two problems at the same time.

The present invention has been made in view of the above-mentioned conventional problems, and in particular, it has high sensitivity to long wavelength light of 750 nm or more, is excellent in dispersion stability of a pigment in a coating, and has image defects, especially reversal. An electrophotographic photoconductor that has few black spots during development and is excellent in stability of charging potential by repetition,
It is an object of the present invention to provide a charge generation layer coating used therein and a method for producing a photoreceptor thereof.

[0012]

In order to achieve the above object, the coating composition for a charge generation layer of the present invention comprises an electrophotographic photoreceptor comprising a conductive support and a charge generation layer and a charge transport layer laminated on the support. The charge generation layer coating material for forming the charge generation layer, characterized in that it comprises an α-type titanyl phthalocyanine, a polyvinyl butyral resin and a melamine resin dispersed in a solvent.

Next, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor comprising a conductive support and a charge generation layer and a charge transport layer laminated on the conductive support. The charge-generating layer is formed by using the charge-generating layer coating material of the present invention and then cured by heat.

Next, a method for producing an electrophotographic photoreceptor of the present invention is a method for producing an electrophotographic photoreceptor comprising a charge generating layer and a charge transporting layer laminated on a conductive support. The charge generation layer is characterized by being coated by a dip coating method using a coating solution prepared by dispersing α-type titanyl phthalocyanine, polyvinyl butyral resin and melamine resin in a solvent, and then thermally curing.

In the above structure, the α-type titanyl phthalocyanine is contained in the X-ray diffraction spectrum at a Bragg angle (2θ ± 0.2 °) of 7.6 °, 10.3 °, 12.7.
°, 16.3 °, 22.7 °, 24.3 °, 25.5
It is preferable that the crystal has a diffraction peak at 2 ° and 28.6 °.

Further, in the above constitution, the melamine resin is preferably an i-butylated melamine resin.
Further, in the above structure, the mixing ratio of the melamine resin is preferably in the range of 10 to 50% by weight with respect to the total amount of the polyvinyl butyral resin and the melamine resin.

Further, in the constitution of the above-mentioned manufacturing method, it is preferable that the curing temperature of the heat curing is in the range of 110 to 130 ° C. Further, in the constitution of the above-mentioned manufacturing method, it is preferable that the curing time of the heat curing is in the range of 30 to 90 minutes.

[0018]

According to the coating composition for a charge generation layer of the present invention, a charge generation layer for forming a charge generation layer for an electrophotographic photoreceptor is prepared by laminating a charge generation layer and a charge transport layer on a conductive support. A layer coating composition, wherein α-type titanyl phthalocyanine, polyvinyl butyral resin and melamine resin, especially i-butylated melamine resin are dispersed in a solvent, or 10-50% by weight of melamine resin based on the total amount of binder resin.
By so doing, it is possible to improve the dispersion stability of the α-type titanyl phthalocyanine pigment in the charge generation layer coating material and improve the occurrence of local unevenness and pigment aggregation during coating. Further, the electrophotographic photoreceptor of the present invention can achieve a highly sensitive electrophotographic photoreceptor in a long wavelength region of 750 nm or more by using α-type titanyl phthalocyanine as a charge generating substance. Further, according to the electrophotographic photoreceptor and the method for producing the same of the present invention, a melamine resin is used as the binder resin of the charge generation layer in addition to the polyvinyl butyral resin, and after coating, thermosetting, particularly a curing temperature of 110 to 1
By setting the curing time to 30 ° C. or 30 to 90 minutes,
It is possible to improve moisture resistance, reduce local carrier injection from the substrate, and improve fog-like black spots.

Furthermore, in the charge generation layer coating material, the electrophotographic photoreceptor and the method for producing the same according to the present invention, α-type titanyl phthalocyanine is used as the charge generation agent, and particularly the Bragg angle (2θ ± 0.2 °) in the X-ray diffraction spectrum. 7.6 °,
10.3 °, 12.7 °, 16.3 °, 22.7 °, 2
By using a crystal that exhibits diffraction peaks at 4.3 °, 25.5 °, and 28.6 ° and using a specific resin combination of polyvinyl butyral resin and melamine resin as the binder resin, The fluctuation of the charging potential is small and the characteristics are very stable.

The reason for the phenomenon of less repeated fluctuations due to the combination of the binder resins is that the binder resin is partially condensed after forming a coating film in a three-component system of α-type titanyl phthalocyanine, polyvinyl butyral resin and melamine resin. It is considered that this is because the dispersion state of the pigment in the charge generation layer is uniform and carrier injection or dark decay is reduced.

[0021]

The present invention will be specifically described below with reference to examples. FIG. 1 is a sectional view showing the structure of a laminated electrophotographic photoconductor of this embodiment. In FIG. 1, a laminated electrophotographic photoreceptor 1 has an organic photosensitive layer 3 on a conductive support 2,
The organic photosensitive layer 3 is formed by stacking a charge generation layer 4 and a charge transport layer 5 thereon. The charge generation layer 4 is composed of a charge generation substance and a binder resin.

In this embodiment, in the electrophotographic photoreceptor comprising a charge generating layer and a charge transporting layer laminated on a conductive support, the charge generating layer is α-type titanyl phthalocyanine and polyvinyl butyral resin as a binder resin. And a coating solution in which a melamine resin is dispersed in a solvent.

First, a method of forming the charge generation layer 4 will be described. The charge generating layer 4 is formed on the conductive support by a dip coating method using the charge generating layer coating material. The α-type titanyl phthalocyanine used in this example has a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum.
7.6 °, 10.3 °, 12.7 °, 16.3 °, 2
It is a crystal showing strong diffraction peaks at 2.7 °, 24.3 °, 25.5 °, and 28.6 °, and is synthesized by a known method. For example, phthalonitrile and titanium tetrachloride are reacted to obtain dichlorotitanium phthalocyanine,
It is hydrolyzed by hot water treatment in the presence of ammonia,
Crude titanyl phthalocyanine is obtained. This crude titanyl phthalocyanine is washed, if necessary, and then subjected to solvent treatment to be crystallized into α-type. At this time, the crude titanyl phthalocyanine may be made amorphous or low crystallized by dry milling, acid pasting or the like before the crystal transition. The polyvinyl butyral resin used in this example is obtained by saponifying a vinyl acetate resin and acetalizing it, and has an unreacted hydroxyl group or carboxyl group at the side chain or terminal depending on its butyralization degree. ,
It is considered that these improve the dispersion stability and adhesiveness of the pigment which is the charge generating substance. Therefore, considering the dispersion stability of the charge generating material, the degree of butyralization is 50.
It is preferably about 70%. If the butyralization degree is too small, it becomes water-soluble, and if the butyralization degree is too large, the affinity with the charge generating substance such as titanyl phthalocyanine decreases, which is not preferable. The polyvinyl butyral resin may have a molecular weight of about 200 to 2,000, but if the molecular weight is too small, the film strength of the charge generating layer will decrease, and if it is too large, the charge generating layer will be subjected to dip coating. It is difficult to form a film when forming a film.

The melamine resin used in this example is n-
It is an alkyl etherified melamine resin such as a butyl etherified melamine resin or an i-butyl etherified melamine resin, and shows the solvent resistance of the charge generation layer formed by partial crosslinking by the condensation reaction with the hydroxyl group contained in the polyvinyl butyral resin. Can be improved. In this example, an i-butylated melamine resin was used. The content of the melamine resin is preferably 10 to 50% by weight based on the total amount of the binder resin in terms of affinity in a mixed system with the polyvinyl butyral resin and dispersion stability of the charge generating substance.

Due to the characteristics, the thickness of the charge generation layer is 0.1 to 1
About μm is preferable. If the film thickness is too thin, the charge generation amount is small and sufficient sensitivity cannot be obtained, and if the film thickness is too thick, the charging property is lowered, and the charging property and the repeated stability of sensitivity are impaired.

When the charge generating layer is formed on the conductive support, a polyvinyl butyral resin or acetic acid is used in order to improve the adhesion between the conductive support and the charge generating layer or prevent the charge injection from the conductive support side. You may provide the 0.1-1 micrometer layer which consists of vinyl resin or polyamide resin.

The solvent for the charge generation layer coating material may be any solvent that dissolves the binder resin, and specifically, alcohols, halogenated hydrocarbons, aromatic hydrocarbons, ketones, esters, Although ethers and the like can be used, from the viewpoint of dispersion stability of the pigment, alcohols, particularly, when α-type titanyl phthalocyanine is used,
n-butanol, s-butanol, n-propanol,
i-Propanol and the like are preferable.

The charge transport layer 5 is formed of a charge transport material and a binder resin. Examples of the charge transport material used in the charge transport layer include alkyl groups, alkoxy groups, amino groups,
Compounds having an electron-donating group such as imide group, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene or derivatives containing them, indole, oxazole,
Examples thereof include heterocyclic compounds such as oxadiazole, carbazole, thiazole, pyrazoline, imidazole and triazole, and derivatives containing them. These charge-transporting substances and binders are dissolved in a suitable solvent, coated by a dip coating method and dried to form a charge-transporting layer.
When the charge transport material is a polymer compound, the charge transport layer may be formed alone without mixing the binder resin. The thickness of the charge transport layer is usually preferably about 5 to 30 μm.

The conductive support 2 may be any known conductive material, and examples thereof include metallic materials such as aluminum, iron and copper, conductive plastics, aluminum iodide, copper iodide and chromium oxide. Alternatively, glass coated with a metal oxide such as tin oxide is used. The thickness is not particularly limited, and usually about 1 mm is used.

(Example 1) A crude titanyl phthalocyanine obtained from phthalonitrile and titanium tetrachloride was treated with acetonitrile to obtain an α-type crystal, and a Bragg angle (2θ ± 0.2 °) 7.6 in an X-ray diffraction spectrum was obtained. ° 10.3
°, 12.7 °, 16.3 °, 22.7 °, 24.3
10 parts by weight of α-type titanyl phthalocyanine (granular particle size of about 0.05 μm), which is a crystal showing strong diffraction peaks at °, 25.5 °, and 28.6 °, and polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., Product name S-REC BL-
1) 4 parts by weight and 1 part by weight of i-butylated melamine resin (manufactured by Dainippon Ink and Chemicals, Inc., trade name G821), 360 parts by weight of 1-propanol, glass beads (diameter 1 mm) 30
0 part by weight was placed in a glass bottle and dispersed by a paint conditioner for 15 hours to obtain a charge generation layer coating material. Using this coating liquid, the coating liquid was pulled up onto an aluminum tube by a dip coating method at a speed of 100 mm / min. A charge generation layer was formed. After coating, heat curing was performed at 120 ° C. for 1 hour.

Then, 4-N, N-diphenylamino-
Using a charge transport layer coating material prepared by dissolving 5 parts by weight of α-phenylstilbene and 5 parts by weight of biphenyl polycarbonate in 45 parts by weight of toluene, dip coating is performed on the charge generation layer,
It was dried at 100 ° C. for 1 hour to form a charge transport layer having a film thickness of 20 μm.

Using the electrophotographic photosensitive drum thus obtained, it was exposed to high temperature and high humidity (33 ° C., 80% RH) for 4 hours.
A 500-sheet continuous image test was performed, and image evaluation and surface potential measurement were performed. For continuous image test evaluation, a commercially available plain paper facsimile (trade name B-77, manufactured by Matsushita Densen Co., Ltd.) was used, and for image evaluation, the fog of images at the initial stage and after 4,500 sheets was measured with a photovoltmeter (MODEL 577). At this time, the difference between the reflection density of the unused paper and the reflection density of the white solid image was defined as ΔPV, and the degree of fogging was evaluated. In addition, the charging potential at that time was measured by a surface electrometer (Model 34 manufactured by Trek Japan Co., Ltd.).
4) was used for measurement. Table 1 shows the evaluation results.

[0033]

[Table 1]

(Example 2) In the charge generation layer of Example 1, instead of the i-butylated melamine resin (manufactured by Dainippon Ink and Chemicals, Inc., G821) as the binder resin, a lower molecular weight i-butylated melamine resin was used. A charge generation layer and a charge transport layer were formed on the conductive support in the same manner as in Example 1 except that (trade name: L145, manufactured by Dainippon Ink and Chemicals, Inc.) was used. High humidity environment 45
Images and charging potentials were evaluated by a 00-sheet continuous image test. Table 1 shows the results.

Example 3 In Example 1, polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name S-REC BL) was used as the binder resin for the charge generation layer.
-1) 4.5 parts by weight of 4 parts by weight, i-butylated melamine resin (manufactured by Dainippon Ink and Chemicals, Inc., trade name G821)
A charge generation layer and a charge transport layer were formed on a conductive support in the same manner as in Example 1 except that 1 part by weight was changed to 0.5 part by weight. Images and charging potentials were evaluated by a 4500-sheet continuous image test. Table 1 shows the results.

Example 4 In Example 1, a polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name S-REC BL) was used as the binder resin for the charge generation layer.
-1) 4 parts by weight to 2.5 parts by weight, i-butylated melamine resin (Dainippon Ink and Chemicals, trade name G821)
A charge generation layer and a charge transport layer were formed on a conductive support in the same manner as in Example 1 except that 1 part by weight was 2.5 parts by weight, and the same manner as in Example 1 was performed under a high temperature and high humidity environment. Images and charging potentials were evaluated by a 4500-sheet continuous image test. Table 1 shows the results.

Comparative Example 1 As a comparative example, an i-butylated melamine resin (manufactured by Dainippon Ink and Chemicals, Inc., trade name G82) in Example 1 was used as a binder resin for the charge generation layer.
Charge generating layer on a conductive support in the same manner as in Example 1 except that 1) was not used and only 5 parts by weight of polyvinyl butyral resin (Sekisui Chemical Co., Ltd., trade name S-REC BL-1) was used. Then, a charge transport layer was formed, and in the same manner as in Example 1, an image and a charging potential were evaluated by a continuous image test of 4,500 sheets under a high temperature and high humidity environment. Table 1 shows the results. (Comparative Example 2) In Example 1, 4 parts by weight of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name S-REC BL-1) as a binder resin for the charge generation layer was 4.75 parts by weight, and i- A charge generation layer and a charge transport layer were formed on a conductive support in the same manner as in Example 1 except that 1 part by weight of a butylated melamine resin (manufactured by Dainippon Ink and Chemicals, Inc., trade name G821) was 0.25 part by weight. Then, in the same manner as in Example 1, the images and the charging potential were evaluated by a continuous image test of 4,500 sheets under a high temperature and high humidity environment. Table 1 shows the results.

[0038]

As described above, according to the coating composition for a charge generating layer of the present invention, α-type titanyl phthalocyanine, polyvinyl butyral resin and melamine resin, especially i-butylated melamine resin are dispersed in a solvent, Alternatively, by setting the melamine resin to 10 to 50% by weight with respect to the total amount of the binder resin, the dispersion stability of the α-type titanyl phthalocyanine pigment in the charge generation layer coating material is improved, and local unevenness during coating or The occurrence of pigment aggregation can be improved.

According to the electrophotographic photoreceptor of the present invention, by using α-type titanyl phthalocyanine as the charge generating substance, it is possible to provide an electrophotographic photoreceptor having a high sensitivity in a long wavelength region of 750 nm or more. Further, according to the electrophotographic photoreceptor and the method for producing the same of the present invention, a melamine resin is used as the binder resin of the charge generation layer in addition to the polyvinyl butyral resin, and after coating, thermosetting, particularly a curing temperature of 110 to 130 ° C or curing time 30-90
By adjusting the amount, it is possible to improve the moisture resistance, reduce the local carrier injection from the substrate, and improve the fog-like black spots.

Furthermore, according to the charge generation layer coating material, the electrophotographic photoreceptor and the method for producing the same of the present invention, α-type titanyl phthalocyanine is used as the charge generation agent, and particularly the Bragg angle (2θ ± 0.2 in the X-ray diffraction spectrum. °) 7.6 °,
10.3 °, 12.7 °, 16.3 °, 22.7 °, 2
By using a crystal having a diffraction peak at 4.3 °, 25.5 °, and 28.6 ° and using a specific resin combination of polyvinyl butyral resin and melamine resin as a binder resin, The fluctuation of the charging potential is small, and the electrophotographic characteristics of the photoconductor can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an electrophotographic photosensitive member according to an embodiment of the present invention.

[Explanation of symbols]

 1 Electrophotographic Photoreceptor 2 Conductive Support 3 Photosensitive Layer 4 Charge Generation Layer 5 Charge Transport Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C09D 129/14 PFQ G03G 5/05 102 (72) Inventor Tetsuya Sato 1006 Kadoma, Kadoma, Osaka Prefecture Within Matsushita Electric Industrial Co., Ltd. (72) Inventor Tsumugi Kobayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (11)

[Claims] 1. A charge generation layer coating material for forming a charge generation layer of an electrophotographic photoreceptor, comprising a charge generation layer and a charge transport layer laminated on a conductive support, wherein α-type titanyl. A coating material for a charge generation layer, which comprises a phthalocyanine, a polyvinyl butyral resin and a melamine resin dispersed in a solvent. 2. The α-type titanyl phthalocyanine has a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum.
7.6 °, 10.3 °, 12.7 °, 16.3 °, 2
The coating material for a charge generation layer according to claim 1, which is a crystal having diffraction peaks at 2.7 °, 24.3 °, 25.5 °, and 28.6 °. 3. The coating material for a charge generating layer according to claim 1, wherein the melamine resin is an i-butylated melamine resin. 4. The mixing ratio of the melamine resin to the total amount of the polyvinyl butyral resin and the melamine resin is 10 to 50.
The charge generation layer coating composition according to claim 1, which is in the range of wt%. 5. An electrophotographic photosensitive member comprising a conductive support, and a charge generation layer and a charge transport layer laminated on the conductive support, wherein the charge generation layer is defined in any one of claims 1 to 4. An electrophotographic photoreceptor, which is a charge-generating layer which is formed by using the coating material for a charge-generating layer described above and then thermoset. 6. A method of manufacturing an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer laminated on a conductive support, wherein the charge generation layer is α-type titanyl phthalocyanine.
A method for producing an electrophotographic photoreceptor, comprising applying a polyvinyl butyral resin and a melamine resin in a solvent and applying the solution by a dip coating method followed by thermosetting. 7. The α-type titanyl phthalocyanine has a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum.
7.6 °, 10.3 °, 12.7 °, 16.3 °, 2
The method for producing an electrophotographic photoreceptor according to claim 6, which is a crystal having diffraction peaks at 2.7 °, 24.3 °, 25.5 °, and 28.6 °. 8. The method for producing an electrophotographic photoreceptor according to claim 6, wherein the melamine resin is an i-butylated melamine resin. 9. The mixing ratio of the melamine resin to the total amount of the polyvinyl butyral resin and the melamine resin is 10 to 50.
The method for producing an electrophotographic photosensitive member according to claim 6, wherein the amount is in the range of wt%. 10. The curing temperature for thermosetting is 110 to 130 ° C.
The method for producing an electrophotographic photosensitive member according to claim 6, which is in the range of. 11. The method for producing an electrophotographic photosensitive member according to claim 6, wherein the curing time of heat curing is in the range of 30 to 90 minutes.