JPH05303213A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having a satisfactory coated surface and causing no image defects. CONSTITUTION:An electric conductive substrate is dip-coated with a coating liq. prepd. by dispersing an azo pigment represented by the formula in at least one kind of solvent selected among 1,2-dimethoxyethane, methyl ethyl ketone and methyl isobutyl ketone to obtain the objective electrophotographic sensitive body. In the formula, (n) is 0 or 1, R1 is H, <=6C alkyl, methoxy or ethoxy and R2 is H, methyl, ethyl or halogen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photosensitive member having a good coated surface.

[0002]

2. Description of the Related Art Inorganic photoconductive substances such as selenium, cadmium sulfide, and silicon have been conventionally known for electrophotographic photoreceptors, and have been extensively studied and put to practical use. In recent years, with respect to these inorganic substances, organic photoconductive materials have been actively researched, and some of them have been put into practical use as electrophotographic photoreceptors.

Generally viewed, an inorganic material has a photosensitive layer formed on a conductive support by a vacuum deposition method or a sputtering method. Manufacturing in a vacuum requires a large-scale manufacturing facility and is not always satisfactory in terms of cost, such as the problem of the growth speed of the photosensitive layer. In comparison with such a situation, the organic material is very excellent in cost because it is possible to coat the photosensitive layer on the conductive support. In addition, environmental pollution due to the toxicity of inorganic materials has become a problem, and electrophotographic photoreceptors made of organic materials are gradually gaining attention for their practical use.

By the way, when an organic material is applied onto a conductive support, a solvent-soluble constituent substance such as a resin can be dissolved in a soluble solvent and applied, but a pigment or the like is generally insoluble in the solvent. It is not possible to apply such constituent substances as they are, and a method of dispersion is necessary. Dispersion described here is to make pigments, etc., into fine particles in a solvent to make them in a suspended state without sediment, and stability of dispersion means that the prepared fine particles are uniform and stable in the solvent for a long period of time. Means saved.

When the dispersion of the pigment is deteriorated, the coated surface becomes rough,
This may cause image failure such as pinholes and uneven density. Further, the dispersed particles settle down over time to lower the image density, and the dispersion liquid thickens to cause fluctuations in the coating amount, which leads to lower productivity.

In order to obtain a good pigment dispersion, a method of controlling the aggregation state by changing a part of the molecular structure of the pigment or mixing pigments having different structures, and There is a method of adsorbing a resin soluble in a solvent. However, in these methods, the electrophotographic properties of the original pigment, that is, the sensitivity and the repetitive characteristics are changed, and the initial purpose as a photoconductor has not been achieved in the basic performance of the pigment.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pigment dispersion liquid having excellent coatability and good stability.

[0008]

As a result of various investigations to achieve the above object, the present inventors have found that the azo pigment represented by the chemical formula 1 is 1,2-dimethoxyethane, methyl ethyl ketone, methyl isobutyl ketone. It was found that it is effective to disperse in at least one solvent selected from the above, and the present invention has been completed.

In the chemical formula 1, n represents 0 or 1, R ₁ represents a hydrogen atom, an alkyl group having up to 6 carbon atoms, a methoxy group or an ethoxy group, and R ₂ represents a hydrogen atom, a methyl group, an ethyl group, Represents a halogen atom such as fluorine, chlorine and bromine.

Hereinafter, each component of the present invention will be described in detail.

First, a well-known electrophotographic photosensitive member is used as a conductive support on which the photosensitive layer of the photosensitive member is formed.
Any of E can be used. Specifically, for example, gold,
Silver, platinum, titanium, aluminum, copper, zinc, iron,
Examples thereof include a drum, a sheet, a belt made of a metal oxide or the like which has been subjected to a conductive treatment, a laminate of these thin films, and a vapor deposit. Further, a conductive substance such as metal powder, metal oxide, carbon black, carbon fiber, copper iodide, charge transfer complex, inorganic salt, and ion conductive polymer electrolyte is coated with a suitable binder and embedded in the polymer matrix. Drums, sheets, belts, etc. made of plastics, ceramics, paper, etc. that have been subjected to a conductive treatment with, and drums, sheets, belts of plastics, ceramics, paper, etc. made conductive by containing such conductive substances Etc.

The photosensitive layer is a pigment-dispersed single layer type in which a pigment as a charge generating substance is dispersed and embedded in a binder, or a single layer type in which a charge generating substance and a charge transfer substance are dispersed and mixed and enclosed in a binder. It is composed of a laminated type in which the generated substance and the charge transfer substance are separated and sealed in a binder. A blocking layer may be provided between the photosensitive layer and the conductive support in order to control the injection of charges from the photosensitive layer to the conductive support, and the surface of the photosensitive layer improves the durability of the photoreceptor. Therefore, a surface layer may be provided.

The charge transfer material used is exemplified by triphenylamine derivatives represented by Chemical Formulas 2 to 6 below.

[0014]

[Chemical 2]

[0015]

[Chemical 3]

[0016]

[Chemical 4]

[0017]

[Chemical 5]

[0018]

[Chemical 6]

Stilbene derivatives represented by Chemical formulas 7 to 15

[0020]

[Chemical 7]

[0021]

[Chemical 8]

[0022]

[Chemical 9]

[0023]

[Chemical 10]

[0024]

[Chemical 11]

[0025]

[Chemical 12]

[0026]

[Chemical 13]

[0027]

[Chemical 14]

[0028]

[Chemical 15]

The butadiene derivatives represented by the chemical compounds 16 and 17,

[0030]

[Chemical 16]

[0031]

[Chemical 17]

Illustrative compounds include, but are not limited to, hydrazone derivatives represented by Chemical formulas 18 to 26.

[0033]

[Chemical 18]

[0034]

[Chemical 19]

[0035]

[Chemical 20]

[0036]

[Chemical 21]

[0037]

[Chemical formula 22]

[0038]

[Chemical formula 23]

[0039]

[Chemical formula 24]

[0040]

[Chemical 25]

[0041]

[Chemical formula 26]

In the multi-layer type photoreceptor, at least the charge transfer material and the binder resin form a charge transfer layer.

As the binder resin, polystyrene,
Acrylic resin represented by polymethylmethacrylate,
Polycarbonate, polyarylate, polyphenylene ether, polyether sulfone, polyester, polyamide, polyimide or the like having a bisphenol A or Z skeleton or other modified skeleton can be used.

In the charge transfer layer, the binder resin is used in the range of 10 to 400 parts by weight with respect to 100 parts by weight of the charge transfer material. The thickness of the charge transfer layer is 5 to 100 μm
Is preferred.

In the electrophotographic photoreceptor according to the present invention, various antioxidants may be added together in order to prevent deterioration due to the oxidation of the organic compounds of the constituent materials, and film-forming property, flexibility and mechanical properties may be added. Well-known plasticizers may be used to improve the strength.

As the charge generating agent, the azo pigment represented by Chemical formula 1 given in Table 1 can be used.

[0047]

[Table 1]

The charge generation layer is composed of a binder resin and additives in addition to the pigment. As the binder resin, butyral resin, phenoxy resin, vinyl chloride / vinyl acetate resin, polyvinyl acetate, polyester, acrylic resin, thermosetting resin, photocurable resin and the like are used. These resins may contribute to the dispersibility of the pigment, but the solubility of the resin used must be taken into consideration. In our experience, butyral resin causes a decrease in sensitivity, phenoxy resin, polyester, etc. cause deterioration of repeatability, and thermosetting resin or photocurable resin deteriorates the storage stability of the dispersion liquid. Intended to improve is a cause of unexpected defects. According to the present invention, it is possible to minimize the influence of these resins and to prepare a good dispersion liquid.

The binder resin is used in an amount of 0 to 1000 parts by weight, preferably 0 to 400 parts by weight, based on 100 parts by weight of the azo pigment as a charge generating substance, and the binder resin may not be used. The thickness of the charge generation layer is 0.1
To 20 μm is preferable.

The blocking layer (undercoat layer) used between the photoreceptor and the conductive support is used by mixing with an alcohol-soluble or water-soluble resin or an inorganic pigment such as titanium oxide. Nylon and methoxymethylated nylon are known as alcohol-soluble resins, and polyethylene glycol, polyvinyl alcohol, polyacrylic acid, etc. are known as water-soluble resins.

The thickness of the undercoat layer is determined depending on the degree of surface roughening of the conductive support and the electrophotographic characteristics at low temperature and low humidity, and it is used at 0.1 to 30 μm.

[0052]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Example 1 1 part by weight of a bisazo pigment of Exemplified Compound P03 and 100 parts by weight of 1,2-dimethoxyethane were dispersed together with glass beads for 2 hours by a paint conditioner. The pigment dispersion thus obtained was dip-coated on a thin aluminum metal plate (JIS standard # 1050) and dried at 80 ° C. for 15 minutes to form a charge generation layer having a thickness of about 0.2 μm.

Next, 10 parts by weight of the hydrazone compound represented by the exemplified compound formula 19, 5 parts by weight of polyarylate resin (U-polymer manufactured by Unitika), 5 parts by weight of modified polycarbonate resin (Z-200 manufactured by Mitsubishi Gas Chemical Co., Inc.), α- Tocopherol (0.2 parts by weight) was dissolved in dichloromethane (200 parts by weight), and this solution was applied onto the above-mentioned carrier generating substance film by a dip coating method to form a charge transfer layer having a dry film thickness of 20 μm.

The laminated electrophotographic photosensitive member thus prepared was mounted on a commercially available office copying machine to form an image, and it was investigated whether or not the image had a failure. The results are given in Table 1.

[0055]

[Table 2]

Examples 2 and 3 Photoreceptors were prepared in the same manner as in Example 1 except that methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) were used as the dispersing solvents, the images were examined, and the results are shown in Table 2.

Example 4 A photoconductor was prepared with 50 parts by weight of 1,2-dimethoxyethane (DME) as the dispersion solvent and 50 parts by weight of MIBK in Example 1, and an image was investigated. The results are given in Table 2.

[0058]

[Table 3]

Comparative Examples 1 to 5 Dispersing solvents were propanol, toluene, dichloroethane,
A photoconductor was prepared using dimethylformamide (DMF) and ethyl acetate in the same manner as in Example 1, and the image was examined.

[0060]

[Table 4]

Example 5 Alcohol-soluble nylon (CM-8000 manufactured by Toray) 1
0 parts by weight was dissolved in 100 parts by weight of methanol and 100 parts by weight of dichloroethane to obtain a metal aluminum thin plate (JI
It was applied by dip coating on S standard # 1050) to form an undercoat layer having a film thickness of 1 μm.

1 part by weight of the bisazo pigment of Exemplified Compound P23 and 100 parts by weight of 1,2-dimethoxyethane were mixed, dispersed with glass beads for 4 hours by a paint conditioner, and dip-coated on the above-mentioned undercoat layer. After drying, a charge generation layer having a thickness of about 0.5 μm was formed.

Next, 8 parts by weight of the hydrazone compound represented by Exemplified Compound 25, 10 parts by weight of a polycarbonate resin (Z-200 manufactured by Mitsubishi Gas Chemical Co., Inc.), and .alpha.-tocopherol 0.
2 parts by weight, 2,5-di-t-butylhydroquinone 0.
1 part by weight was dissolved in 200 parts by weight of dichloromethane, and this solution was applied onto the film of the above-mentioned carrier-generating substance by a dip coating method to form a charge transfer layer having a dry film thickness of 23 μm.

An image test was conducted on this photoreceptor in the same manner as in Example 1. The results are given in Table 4.

Examples 6 and 7 MEK and MIBK were used as the azo pigment dispersion solvent in Example 4.
Similarly, a photoconductor was prepared and an image test was conducted, and the results are shown in Table 4.

[0066]

[Table 5]

Comparative Examples 6 to 10 The dispersing solvent used in Example 5 was propanol, toluene,
Dichloroethane, dimethylformamide (DMF),
A photoconductor was prepared in the same manner as ethyl acetate, images were examined, and the results are shown in Table 5.

[0068]

[Table 6]

Example 8 1 part by weight of a bisazo pigment of Exemplified Compound P25 and 0.2 part by weight of butyral resin (# 3000-K manufactured by Denki Kagaku Co., Ltd.) were added.
2-dimethoxyethane was mixed with 100 parts by weight, dispersed with glass beads for 4 hours by a paint conditioner, and dip-coated on the undercoat layer prepared in the same manner as in Example 5 8
After drying at 0 ° C for 15 minutes, a charge generation layer having a thickness of about 0.3 µm was formed.

Next, 10 parts by weight of the stilbene compound represented by the exemplified compound chemical formula 11, 10 parts by weight of a polycarbonate resin (K-1300 manufactured by Teijin Chemicals Ltd.), and 200 parts by weight of dichloromethane were dissolved to form a carrier-generating substance on the film.
This solution is applied by a dip coating method to give a dry film thickness of 23μ.
m charge transfer layer was formed.

An image test was conducted on this photoreceptor in the same manner as in Example 1. The results are given in Table 4.

Examples 9 to 11 The binder resin for the charge generation layer in Example 7 was phenoxy resin (PKHJ manufactured by Union Carbide), polyester (V-200 manufactured by Toyobo), vinyl chloride / vinyl acetate resin (manufactured by Union Carbide). A similar image test was performed as VYHH). The results are given in Table 6.

[0073]

[Table 7]

[0074]

As is apparent from the above, according to the present invention, it is possible to provide an electrophotographic photosensitive member having a good coating surface with no image failure.

Claims (1)

[Claims] 1. A coating solution in which an azo pigment represented by the following chemical formula 1 is dispersed in at least one solvent selected from 1,2-dimethoxyethane, methyl ethyl ketone, and methyl isobutyl ketone, is coated on a conductive support. A method for manufacturing an electrophotographic photosensitive member, characterized by applying by an immersion coating method. [Chemical 1] (In the formula 1, n represents 0 or 1, R ₁ represents a hydrogen atom, an alkyl group having up to 6 carbon atoms, a methoxy group or an ethoxy group, and R ₂ represents a hydrogen atom, a methyl group, an ethyl group or a halogen atom. Represents.)