JPH06295084A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form an undercoat layer excellent in smoothness by spray coating with a coating material based on alcohol-soluble nylon and contg. an alcoholic solvent having a specified b.p. CONSTITUTION:An undercoat layer is formed by spray coating with a coating material for forming the undercoat layer contg. a bonding resin and a solvent dissolving the bonding resin and having 130-220 deg.C b.p. Material used in the undercoat layer is based on an alcohol-soluble resin and the solvent is prepd. by mixing one or more kinds of alcoholic solvents each having <=130 deg.C b.p. such as methanol, ethanol, propanol and butanol as principal solvents with one or more kinds of alcoholic solvents each having 130-220 deg.C b.p. such as amyl alcohol, hexyl alcohol, phenol, benzyl alcohol and propylene glycol as subsidiary solvents. The content of the subsidiary solvents is 3-20wt.% of the total amt. of the coating material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having an undercoat layer spray-coated.

[0002]

2. Description of the Related Art Conventionally, a dip coating method has been generally known as a coating method for an electrophotographic organic photoconductor, but this coating method requires a large amount of paint in order to improve mass productivity. However, there are problems such as a large difference in film thickness between the upper end and the lower end of coating. A spray coating method has been studied as a coating method for solving these drawbacks. For example, mass production is possible with a small amount of paint, but sufficient smoothness of the coating film is not yet obtained, and solvent vapor pressure and water vapor pressure are adjusted to improve the smoothness of the coating film. Proposals have been made such as spray coating (JP-A-54-55040) and air spraying by adjusting the ratio of paint and air (JP-A-63-41859).

[0003]

However, in these methods, it is a reality that the apparatus is complicated, the adjustment is complicated, and a sufficient one is not obtained yet.

The problem to be solved by the present invention is to provide a method for producing a photoconductor for electrophotography which improves the smoothness of a coating film and is more practically preferable by a simple method.

[0005]

The inventors have focused on developing a spray coating method for electrophotographic photoreceptors. As a result, alcohol-soluble nylon is the main component,
It has been found that an undercoat layer having excellent smoothness of the coating film can be obtained by spray coating using a coating material containing an alcohol solvent having a boiling point of 220 ° C., and completed the present invention.

That is, in order to solve the above-mentioned problems, the present invention provides a method for producing an electrophotographic photoreceptor in which an undercoat layer is formed on a support and then a photosensitive layer is formed on the undercoat layer. Boiling point of 130 to dissolve the binder resin and its binder resin
Provided is a method for producing an electrophotographic photoreceptor, which comprises forming an undercoat layer by spray coating using a paint for forming an undercoat layer containing a solvent at 220 ° C.

The undercoat layer is provided between the support and the photosensitive layer in order to improve the adhesion between the support and the photosensitive layer and prevent the injection of free charges from the support to the photosensitive layer.

The material used for the undercoat layer contains an alcohol-soluble resin as a main component, and as a solvent thereof, an alcohol solvent having a boiling point of 130 ° C. or lower such as methanol, ethanol, propyl alcohol, butyl alcohol is used as a main solvent, and amyl alcohol, Boiling point of hexyl alcohol, phenol, benzyl alcohol, propylene glycol, etc. 13
An alcohol-based solvent at 0 to 220 ° C. is used as a secondary solvent, and at least one main solvent and at least one secondary solvent are mixed to obtain a spray coating material. However, the content of the sub-solvent is preferably in the range of 3 to 20% by weight, and particularly preferably in the range of 3 to 10% by weight, based on the entire coating material. As the non-volatile component, it is possible to add a pigment component such as titanium oxide or other additives in addition to the resin component.

The present invention will be described in detail below.

In the present invention, an undercoat layer is provided on a support, and a photosensitive layer made of a photoconductive material is further formed to be used as an electrophotographic photosensitive member. The photosensitive layer has various structures. be able to. Examples thereof are shown in FIGS.
The electrophotographic photoreceptor of FIG. 1 has a photosensitive layer obtained by dispersing a charge generating material in a binder resin on an undercoat layer. The electrophotographic photoreceptor of FIG. 2 has a photosensitive layer formed by dispersing a charge generating material and a charge transporting material in a binder resin on an undercoat layer. The electrophotographic photoreceptors of FIGS. 3 and 4 are provided with a photosensitive layer in which a charge generating layer mainly composed of a charge generating material and a charge transporting layer mainly composed of a charge transporting material are laminated on an undercoat layer. . The thickness of the undercoat layer is 0.01 to
The range of 20 μm is preferable, and the range of 0.1 to 5 μm is particularly preferable. The film thickness of the photosensitive layer is preferably in the range of 5 to 50 μm. Also, if necessary, wear resistance on the photosensitive layer,
A surface protective layer may be formed to improve chemical resistance and the like.

The material of the support used in the electrophotographic photoreceptor of the present invention is, for example, a metal drum of aluminum, aluminum alloy, copper, nickel, zinc, stainless steel, or a plastic sheet or film made of aluminum or tin oxide. , A material obtained by vapor deposition of a conductive material such as indium oxide, or paper or resin that has been subjected to a conductive treatment.

Examples of the charge generating material used in the photosensitive layer include azo pigments, quinone pigments, perylene pigments, indigo pigments, thioindigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, quinacridone pigments, Quinoline pigments, lake pigments, azo lake pigments, anthraquinone pigments, oxazine pigments, dioxazine pigments, triphenylmethane pigments, azurenium dyes, squarium dyes, pyrylium dyes,
Various organic pigments and dyes such as triallylmethane dye, xanthene dye, thiazine dye, and cyanine dye, and further amorphous silicon, amorphous selenium, tellurium,
Inorganic materials such as selenium-tellurium alloy, cadmium sulfide, antimony sulfide, zinc oxide and zinc sulfide can be mentioned.

These materials can be used in the photosensitive layer by dispersing and coating them in a binder resin, or by forming a film by means of vacuum deposition, sputtering, CVD method or the like.

The charge-generating substance is not limited to those listed here, and may be used alone or in combination of two or more when used.

The charge-transporting substance is generally classified into two types, a substance that transports an electron and a substance that transports a hole, and both can be used in the electrophotographic photoreceptor of the present invention.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone. , 9-dicyanomethylene-2,4,7-trinitrofluorenone, 9-dicyanomethylene-2,4,5,7
-Tetranitrofluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, tetranitrocarbazole chloranil, 2,3-
Dichloro-5,6-dicyanobenzoquinone, 2,4,7
-Organic compounds such as trinitro-9,10-phenanthrenequinone, tetrachlorophthalic anhydride, diphenoquinone derivative, and inorganic materials such as amorphous silicon, amorphous selenium, tellurium, selenium-tellurium alloy, cadmium sulfide, antimony sulfide, zinc oxide, zinc sulfide Is mentioned.

As the hole-transporting substance, examples of low-molecular compounds include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-phenylcarbazole,
Alternatively, N-methyl-2-phenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, p-N, N-dimethylaminobenzaldehyde diphenylhydrazone, p Hydrazones such as -N, N-diethylaminobenzaldehyde diphenylhydrazone and p-N, N-diphenylaminobenzaldehyde diphenylhydrazone, 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1 -Phenyl-3- (p-diethylaminostyryl) -5- (p-
Pyrazolines such as diethylaminophenyl) pyrazoline, N, N′-diphenyl-N, N′-bis (methylphenyl) benzidine, N, N′-diphenyl-N, N ′
Benzidine compounds such as bis (ethylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (propylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (chlorophenyl) benzidine, Triphenylamine, N, N, N ', N'-tetraphenyl-
1,1'-diphenyl-4,4'-diamine, N, N '
-Diphenyl-N, N'-bis (3-methylphenyl)
Examples include -1,1'-biphenyl-4,4'-diamine and the like. Further, as the polymer compound, for example, poly-
N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin,
Examples thereof include ethylcarbazole-formaldehyde resin, triphenylmethane polymer, polysilane and the like.

These materials can be used in the photosensitive layer by dispersing them in a binder resin and coating them, or by forming them into a film by means of vacuum vapor deposition, sputtering, CVD or the like.

The charge-transporting substance is not limited to those listed here, and may be used alone or in combination of two or more when used.

It is also possible to use additives such as a plasticizer, a sensitizer, a surface modifier and an antioxidant together with these charge transport agents.

Examples of the plasticizer include biphenyl, biphenyl chloride, o-terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene and various fluorohydrocarbons. Etc.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B, cyanine dye, merocyanine dye, pyrylium dye and thiapyrylium dye.

Examples of the surface modifier include silicone oil and fluororesin.

Examples of the antioxidants include phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants and the like.

The binder resin for the photosensitive layer is preferably a high molecular polymer capable of forming an electrically insulating film. Examples of such high molecular weight polymers include polycarbonate,
Polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate- Maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-
Alkyd resin, poly-N-vinylcarbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxy-methyl cellulose, vinylidene chloride-based polymer latex, polyurethane, and the like, It is not limited to these. These binder resins may be used alone or in admixture of two or more.

Further, as a material used for the surface protective layer provided on the photosensitive layer, if necessary, a polymer compound used for the binder resin of the photosensitive layer, or a material for imparting conductivity thereto Examples thereof include those obtained by dispersing additives, and thin films of amorphous silicon, amorphous silicon carbide, amorphous carbon, diamond, and the like. This surface protective layer is formed by coating the above material on the photosensitive layer, vacuum deposition, sputtering, CVD.
It can be formed by a method such as a method.

When the photosensitive layer of the electrophotographic photosensitive member is formed by coating, a paint prepared by dissolving the above charge generating material or charge transporting substance in a binder resin or the like is dissolved in a solvent. The solvent that dissolves is different depending on the type of binder resin, but is preferably selected from those that do not dissolve the lower layer. Specific examples of organic solvents include alcohols such as methanol, ethanol and n-propanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylformamide and N, N-dimethylacetamide. Ethers such as tetrahydrofuran, dioxane and methyl cellosolve; Esters such as methyl acetate and ethyl acetate; Sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane; Aliphatic halogenation such as methylene chloride, chloroform, carbon tetrachloride and trichloroethane hydrocarbon;
Benzene, toluene, xylene, monochlorobenzene,
Examples thereof include aromatics such as dichlorobenzene.

As the coating method, for example, dip coating method, spray coating method, spinner coating method, bead coating method, wire bar coating method, blade coating method, roller coating method,
A coating method such as a curtain coating method can be used.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. In the examples, "part" means "part by weight".

Example 1 As a support, a mirror-finished aluminum drum having an outer diameter of 30 mm and a length of 260 mm, which had been washed with triethane, was prepared.

Next, an alcohol-soluble resin (trade name "C
M-8000 "manufactured by Toray Industries, Inc.) 3 parts methanol (boiling point 65
C.) 70 parts, n-butanol (boiling point 118.degree. C.) 20 parts and amyl alcohol (boiling point 138.degree. C.) 10 parts were used, drum rotation speed: 300 rpm, nozzle distance:
40 mm, nozzle traverse speed: 300 mm / min, number of coatings: 3
It was applied by the spray coating method under the same conditions as above and dried at 120 ° C. for 10 minutes to obtain an undercoat layer having a film thickness of about 1 μm. Two of these drums were produced, one of which was used as a sample for measuring the film thickness distribution of the coating film, and the other one was formed with a charge generation layer and a charge transport layer to obtain an electrophotographic photoreceptor. The spray coater used was an aero coat system manufactured by Nordson.

As the charge generating material, a material obtained by synthesizing titanyl phthalocyanine and recrystallizing it from a concentrated sulfuric acid solution was used. Next, the obtained crystals were mixed with an attritor mill to 9
5 parts crushed at 0 ° C. for 90 minutes were mixed with 5 parts butyral resin (trade name “S-REC BL-1” manufactured by Sekisui Chemical Co., Ltd.) and 90 parts methylene chloride, and dispersed for a charge generation layer using a vibration mill. A liquid was obtained. This coating material was applied onto the undercoat layer by dip coating to form a charge generation layer having a thickness of 0.3 μm after drying.

Next, the following structural formula (I), which is a hole-transporting substance, is used.

[0034]

[Chemical 1]

A solution prepared by dissolving 9 parts of a hydrazone compound represented by and 10 parts of a commercially available polycarbonate (trade name "UPILON Z-200" manufactured by Mitsubishi Gas Chemical Co., Inc.) as a binder resin in 60 parts of methylene chloride and 20 parts of monochlorobenzene. After coating by the dipping method, the charge transport layer having a thickness of 20 μm was formed by drying to obtain an electrophotographic photoreceptor.

Example 2 A sample for measuring the film thickness distribution of the undercoat layer and an electronic sample were prepared in the same manner as in Example 1 except that propylene glycol (boiling point 188 ° C.) was used instead of the amyl alcohol of Example 1. A photographic photoreceptor was obtained.

Example 3 A sample for measuring the film thickness distribution of the undercoat layer and an electron were prepared in the same manner as in Example 1 except that benzyl alcohol (boiling point 205 ° C.) was used in place of the amyl alcohol of Example 1. A photographic photoreceptor was obtained.

Comparative Example 1 The film thickness of the undercoat layer was the same as in Example 1 except that 80 parts of methanol and 20 parts of n-butanol were used instead of the solvent composition of the undercoat layer of Example 1. A sample for distribution measurement and a photoconductor for electrophotography were obtained.

(Comparative Example 2) Instead of the amyl alcohol of Example 1, 2-ethylhexyl alcohol (boiling point 184
(C) was used to obtain a sample for measuring the film thickness distribution of the undercoat layer and an electrophotographic photoreceptor in the same manner as in Example 1. Note that 2-ethylhexyl alcohol was not soluble in the resin used.

When the undercoat layers of Examples 1 to 3 and Comparative Examples 1 and 2 were visually observed, Examples 1 to 3 were almost smooth coating films, but Comparative Examples 1 and 2 were partially clouded. It was

(Evaluation Result) (Measurement of Film Thickness Distribution) In order to quantitatively evaluate the smoothness of the undercoat layer coating film, a spectral reflection interference type film thickness measuring instrument TFM-1 is used.
20AF (manufactured by Oak Manufacturing Co., Ltd.) was used to measure the film thickness of the undercoat layer at 36 points on each drum. The results are shown in Table 1. In addition, in Comparative Examples 1 and 2, a portion not clouded was measured.

[0042]

[Table 1]

As is clear from Table 1, the samples of Examples according to the production method of the present invention have a significantly smaller standard deviation than the Comparative Examples, and the smoothness of the coating film is remarkably good.

(Printing Characteristics) Next, an electrophotographic photoreceptor having a charge generation layer and a charge transport layer laminated on an undercoat layer was used at a high temperature and high humidity (35 ° C./8) using a commercially available laser beam printer.
The printing characteristics were examined under the condition of 5% RH). The results are shown in Table 2.

[0045]

[Table 2]

As can be seen from Table 2, the samples of the examples according to the present invention have markedly better printing characteristics than the comparative examples.

[0047]

According to the manufacturing method of the present invention, it is possible to improve the smoothness of the coating film of the undercoat layer and to provide a more preferable electrophotographic photoreceptor in a simple manner. As a result, the printing characteristics of the obtained electrophotographic photosensitive member are improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of an electrophotographic photoreceptor of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present invention.

[Explanation of symbols]

 1 Support 2 Subbing Layer 3a Photosensitive Layer 3b Photosensitive Layer 3c Photosensitive Layer 3d Photosensitive Layer 4 Charge Generating Material 5 Binder 6 Charge Transporting Material 7 Charge Generating Layer 8 Charge Transporting Layer

Claims (4)

[Claims] 1. A binder resin and a boiling point at which the binder resin is dissolved in a method for producing an electrophotographic photoreceptor, which comprises forming a subbing layer on a support and then forming a photosensitive layer on the subbing layer. A method for producing an electrophotographic photoreceptor, comprising forming an undercoat layer by spray coating using a coating material for forming an undercoat layer containing a solvent at 130 to 220 ° C. 2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein an alcohol-soluble resin is contained as a binder resin in the undercoat layer forming coating material. 3. The electrophotographic photoreceptor according to claim 1, wherein the solvent for dissolving the binder resin in the undercoat layer-forming coating material is an alcohol solvent having a boiling point of 130 to 220 ° C. Production method. 4. The method for producing an electrophotographic photoreceptor according to claim 3, wherein the alcohol solvent according to claim 3 is contained in the undercoat layer forming coating material in an amount of 3 to 20% by weight.