JPH04142551A - Electrophotographic sensitive body and production thereof - Google Patents

Abstract

PURPOSE:To obtain excellent images by applying a coating liquid for forming a charge generating layer consisting of an org. solvent contg. >=4C alcohol in its solvent component, selenium powder or selenium alloy powder and a binder resin soluble in the org. solvent. CONSTITUTION:The charge generating layer 2 provided on a conductive base 4 is formed by coating the base with the coating liquid for forming the charge generating layer consisting of the org. solvent contg. >=4C alcohol as its one component, the selenium or selenium alloy particles and the binder resin soluble in the org. solvent. For example, amorphous selenium and trigonal selenium are used as the selenium and selenium alloy of the coating liquid prepd. by dispersing the selenium powder or selenium alloy powder in the binder resin. The content of the selenium or selenium alloy in the binder resin is specified to 30 to 80vol.% and the film thickness of the charge generating layer is specified to 0.01 to 5mum. The stability of the selenium powder particles or selenium alloy particles in the coating liquid is improved in this way and the storage stability and production stability of the coating liquid are improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electrophotographic photoreceptor and a method for manufacturing the same.

(Prior Art) Conventionally, electrophotographic photoreceptors have been known to include those containing an inorganic photoconductive substance and those containing an organic photoconductive substance, and the latter particularly has advantages in terms of productivity, low cost, and safety. It is widely used due to its gender, etc. In addition, in recent years, functionally separated electrophotographic photoreceptors in which photoreceptor functions are shared among multiple members have been developed to improve electrophotographic properties such as charge retention, repetition stability, photoresponsiveness, spectral characteristics, and mechanical strength. Many proposals have been made.

Such a functionally separated organic electrophotographic photoreceptor is one in which a charge generation layer and a charge transport layer are provided on a conductive support, or the charge generation agent in the charge generation layer is a bisazo pigment or the like. Organic pigments such as fused polycyclic pigments have been used.

However, organic pigments have low charge generation efficiency, and electrophotographic photoreceptors formed using such organic pigments have not always been satisfactory in terms of sensitivity.

(Problems to be Solved by the Invention) By the way, an electrophotographic photoreceptor using a selenium or selenium alloy-based inorganic photoconductive material as a charge-generating material is superior to one using the above-mentioned organic pigment in terms of sensitivity. Although it is satisfactory, the coating liquid for forming a charge generation layer in which selenium or selenium alloy particles are dispersed in a binder resin is not yet satisfactory in terms of storage stability and manufacturing stability, and There is a problem in that the coating liquid changes due to this, and as a result, the electrical characteristics and image quality of the electrophotographic photoreceptor obtained deteriorate.

The present invention has been made in view of the above-mentioned problems in the conventional technology.

Accordingly, an object of the present invention is to provide an electrophotographic photoreceptor that has high chargeability, low residual potential, and does not cause image defects such as white spots, dark spots, roughness, density unevenness, and fog.

Another object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor using a coating liquid for forming a charge generation layer containing selenium or selenium alloy particles and having improved storage stability and manufacturing stability. be.

(Means for Solving the Problems) As a result of study, the present inventors have found that when an alcohol having a carbon number of 4 or more is contained in a coating solution, selenium powder particles or selenium alloy powder particles become stable in the coating solution. The present inventors have discovered that the properties of the electrophotographic photoreceptor are improved, the storage stability and manufacturing stability of the coating solution are improved, and the electrophotographic characteristics and image quality characteristics of the formed electrophotographic photoreceptor can be improved, and the present invention has been completed.

The present invention provides an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer laminated on a conductive support, wherein the charge generation layer contains an alcohol having 4 or more carbon atoms as part of a solvent component. The layer is characterized by being formed by applying a coating liquid for forming a charge generation layer comprising an organic solvent, selenium powder or selenium alloy powder, and a binder resin soluble in the organic solvent.

The electrophotographic photoreceptor of the present invention is manufactured by coating a charge generation layer forming coating liquid and a charge transport layer forming coating liquid on a conductive support; As a coating liquid, a coating liquid is used which is composed of an organic solvent containing an alcohol having 4 or more carbon atoms as part of the solvent component, selenium powder or selenium alloy powder, and a binder resin soluble in the organic solvent.

The present invention will be explained in detail below.

1 and 2 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention. In FIG. 1, a charge generation layer 2 is provided on a conductive support 4, and a charge transport layer 1 is provided thereon, and in FIG. 2, a subbing layer 3 is further provided. There is.

In the electrophotographic photoreceptor of the present invention, the conductive support includes a drum made of metal such as aluminum, copper, iron, zinc, and nickel, and a drum made of metal such as aluminum, copper, iron, zinc, and nickel, and a drum made of metal such as aluminum, copper, gold, silver, and the like on a sheet, paper, plastic, or glass. Depositing metals such as platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium, depositing conductive metal compounds such as indium oxide, tin oxide, laminating metal foil, or carbon black. , indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide, etc., are dispersed in a binder resin and applied to conductive treatment using known materials such as drums, sheets, and plates. be able to.

Further, if necessary, the surface of the conductive support can be subjected to various treatments as long as the image quality is not affected. For example, surface oxidation treatment, chemical treatment, coloring treatment, etc. can be performed.

The charge generation layer provided on the conductive support has 4 carbon atoms.
An organic solvent containing the above alcohol as one component,
The selenium powder or selenium alloy powder is dispersed in the binder resin, which is formed by applying a coating liquid for forming a charge generation layer consisting of selenium or selenium alloy fine particles and a binder resin soluble in the organic solvent. Selenium and selenium alloys include amorphous selenium, trigonal selenium,
Mention may be made of selenium-tellurium alloys, selenium-tellurium-arsenic alloys, and mixtures thereof. Among these, trigonal selenium is preferable as a charge generating agent because it has superior sensitivity and spectral properties compared to vitreous selenium, and it is particularly preferable to use undoped trigonal selenium alone.

As the binder resin, well-known ones such as polycarbonate, polystyrene, polyester, polyvinyl butyral, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether, polybutadiene, polyurethane, epoxy Resin etc. are used. Several types of these may be used in combination.

The content of selenium or selenium alloy in the binder resin is
30 to 80% by volume, particularly preferably 50 to 70% by volume. If the content of selenium or selenium alloy is less than 30% by volume, there may be a problem of insufficient sensitivity of the electrophotographic photoreceptor, whereas if it is more than 80% by volume, the charging property will be decreased and the adhesion with the charge generation layer may be impaired. ” This may lead to the problem of extremely poor adhesion.

Further, the thickness of the charge generation layer is 0. It is about 0.1 to 5 tm, preferably about 0.03 to 2 tm. If the film thickness is larger than the above range, problems such as a decrease in chargeability, an increase in dark decay, and a decrease in repetition stability will occur, and if it is smaller, the sensitivity will decrease.

In the present invention, when forming the charge generation layer, the selenium powder or selenium alloy powder is dispersed together with a binder resin and an organic solvent to prepare a coating liquid for forming the charge generation layer.

As the organic solvent, a mixed solvent containing an alcohol having 4 or more carbon atoms as a part of the solvent component is used.

Two or more types of alcohols having 4 or more carbon atoms may be used as a mixture if necessary. For example, ■-butanol, i-
Butanol, ■-pentanol, 2-pentanol, 3
-Pentanol etc. are preferably used.

Various organic solvents can be used in combination with the above-mentioned alcohols, and preferred examples include n-butyl acetate, isobutyl acetate, cyclohexanone, toluene, xylene, chlorobenzene, methyl ethyl ketone, dioxane, tetrahydrofuran, and cellosolve acetate. Can you use it? Two or more of these may be used in combination.

The content of the alcohol having 4 or more carbon atoms in the organic solvent is preferably in the range of 5 to 90% by weight based on the total amount of the solvent. If the alcohol content is less than 5% by weight, the storage stability of the coating solution tends to decrease, and as the coating solution ages, the formed coating film becomes uneven, resulting in copies with defective image quality. It becomes like this. Also, 90% by weight
If the amount exceeds 1, the dispersibility of the selenium powder or selenium alloy powder decreases, and the coating film formed becomes rough, causing fog on copies.

In the present invention, it is necessary to select and use the above-mentioned binder resin that is soluble in the above-mentioned mixed organic solvent. In that case, each of the alcohol having 4 or more carbon atoms and the other organic solvent constituting the mixed organic solvent may be a poor solvent for the binder resin, and in short, the binder resin dissolves in the mixed organic solvent. You can use it if it is.

Dispersion means for dispersing the selenium powder or selenium alloy powder in a solution consisting of a binder resin and an organic solvent include:
Commonly used mills such as a whole mill, roll mill, sand mill, and attritor can be used.

The coating liquid for forming a charge generation layer obtained as described above is
It is coated on a conductive support, and coating methods include blade coating method, Mayer bar coating method,
Conventional methods such as spray coating, dip coating, bead coating, curtain coating, etc. can be used. However, the dip coating method is most suitable for the present invention.

The charge transport layer provided on the charge generation layer is formed by containing a charge transport agent in a suitable binder resin.

As the charge transport agent, oxadiazole derivatives such as 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1-[pyridyl- (2)) Pyrazoline derivatives such as -5-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, aromatic tertiary amino compounds such as triphenylamine and dibenzylaniline, N,N'-diphenyl -N,N'-bis(3-methylphenyl)-[1,1-biphenyl]-4,4'-diamine and other aromatic diamine compounds, 3-(4'-dimethylaminophenyl)-5,6- di(methoxyphenyl)
1.2.4-) riazine derivatives such as -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,
Hydrazone derivatives such as 1-diphenylhydrazone, 2-
Quinazoline derivatives such as phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6hydroxy-2,3-di(p-methoxyphenyl)benzofuran, p-(2,
α-stilbene derivatives such as (2-diphenylvinyl)-N,N-diphenylaniline, “Journal of Imaging Science
29 near ~ 10 (1
985), carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and its derivatives, poly-γ-rubazolylethyl curtanate and its derivatives, as well as pyrene, polyvinylpyrene, Polyvinylanthracene, polyvinylacridine, poly-9-biphenylanthracene,
Pyrene-formaldehyde resin, ethylcarbazole-
Known charge transport agents such as formaldehyde resins can be used. In addition, these charge transport agents may be used alone or in combination.
More than one species can be mixed and used.

Furthermore, the binder resins include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, vinyl chloride resin, vinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, butylene butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, and chloride resin. Vinyl-vinyl acetate copolymer, vinyl chloride-vinyl acetate-
Known resins such as maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene alkyd resin, and poly-N-vinylcarbazole can be used.

Further, these binder resins can be used alone or in combination of two or more.

The blending ratio (weight ratio) of charge transport agent and binder resin is 10:1
The range of 1:5 is preferable.

The thickness of the charge transport layer is generally 5 to 50, preferably 1
It is set in the range of 0 to 30ρ.

The charge transport layer can be formed by dissolving the above-mentioned charge transport agent and binder resin in a suitable solvent to prepare a charge transport layer forming coating solution, and coating the solution on the charge generation layer.

Solvents for forming the coating solution include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated fats such as methylene chloride, chloroform, and ethylene chloride. Common organic solvents include hydrocarbons, tetrahydrofuran, cyclic or linear ethers such as ethyl ether, and these can be used alone or in combination of two or more.

As a coating method, conventional methods such as a plate coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, and a curtain coating method can be used.

In the electrophotographic photoreceptor of the present invention, a subbing layer may be provided between the conductive support and the charge generation layer. This undercoat layer prevents charge injection from the conductive support to the charge generation layer during charging, and also has the function of integrally adhering and holding the charge generation layer to the conductive support, or in some cases acts as a conductive layer. It shows the effect of preventing light from being reflected from the support.

Materials used for the undercoat layer include polyethylene, polypropylene, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, vinylidene chloride resin, Known resins such as polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, water-soluble polyester, nitrocellulose, casein, and gelatin can be used.

The undercoat layer may be formed using an organic zirconium compound such as carbon dioxide, a zirconium chelate compound, a zirconium alkoxide, or a silane coupling agent.

Examples of the zirconium chelate compound include zirconium tetraacetonate, ruconium tetrabutoxide, and tributoxyzirconium acetylacetonate.

Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxinelan, γ-glycidquinpropyltrimethoxylan, γ-methacryloxypropyltrimethoxylan Silane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-
Examples include aminoethylaminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and β-3,4-epoxycyclohexylethyltrimethoxysilane.

The thickness of the undercoat layer is generally set to 0.01 to 5 p, preferably 0.2 to 2 p.

The undercoat layer can be formed by dissolving the above-mentioned resin, zirconium compound, or silane coupling agent in a suitable solvent and coating the solution on the conductive support.

As the solvent, for example, alcohols such as ethanol, methanol, propatool, and butanol, aromatic hydrocarbons such as toluene, and esters such as ethyl acetate and cellosolve acetate can be used alone or in combination.

As a coating method, the same coach ink method as described in connection with the formation of the charge transport layer can be used.

(Example) The present invention will be explained below using examples.

Example 1 A coating solution for forming an undercoat layer having the following composition was applied to an aluminum pipe by dip coating, and the film thickness after drying was 1.
An additional subbing layer was formed.

Alcohol-soluble polyamide 10 parts by weight (N-
Methkin methylated nylon) (Laccamite 5003, manufactured by Dainippon Ink & Chemicals) Methanol 150 parts by weight Water
40 parts by weight Next, the following components were dispersed for 40 hours in a sand grind mill using glass beads with a diameter of 1 mm as media.

Granular trigonal selenium: 87 parts by weight Partially acetoacetalized poly: 13 parts by weight Vinyl butyral resin (BX-1, manufactured by Tsukiki Kagaku ■) i-Butanol: 123 parts by weight Isobutyl acetate: 77 parts by weight Based on 30 parts by weight of the resulting dispersion Then, 57 parts by weight of l-butanol was added to dilute the mixture to obtain a coating solution for forming a charge generation layer.

Using this coating liquid for forming a charge generation layer, it was applied by dip coating onto the subbing layer on an aluminum cylinder.
The mixture was dried by heating at ℃ for 5 minutes to form a charge generation layer having a thickness of about 0.1 tm.

Next, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1-biphenyl]-4.4'-
A coating solution for forming a charge transport layer was prepared by dissolving 10 parts by weight of diamine and 10 parts by weight of polycarbonate Z resin in 80 parts by weight of monochlorobenzene. This coating solution was applied onto the charge generation layer and dried with hot air at 100° C. for 60 minutes to form a charge transport layer having a thickness of 25%.

The electrophotographic photoreceptor thus obtained was designated as Sample 1.

One month after the manufacture of Sample 1, an electrophotographic photoreceptor was prepared using the charge generation layer forming coating liquid used in the manufacture of Sample 1 in the same manner as described above. This was designated as sample 2.

These samples 1 and 2 were transferred to an electrophotographic copying machine (
It was installed on a modified FX-2700 machine (manufactured by Fuji Xerox), and the electrical characteristics and image quality were evaluated. The results will be described in Part 1 below.
Shown in the table.

Example 2 A subbing layer was formed on an aluminum cylinder in the same manner as in Example 1.

Next, the following components were dispersed for 40 hours in a sand grind mill using a glass piece with a diameter of 1 mm as the media.

Granular trigonal selenium 87 parts by weight Partially acetoacetalized poly 13 parts by weight Vinyl butyral resin (BX-1, manufactured by Sekisui Chemical Co., Ltd.) ■-Butanol 39 parts by weight Isobutyl acetate 161 parts by weight Based on 30 parts by weight of the resulting dispersion Then, 57 parts by weight of i-butanol was added to dilute the mixture to obtain a coating solution for forming a charge generation layer.

An electrophotographic photoreceptor was prepared in the same manner as Samples 1 and 2 of Example 1 using the obtained coating liquid for forming a charge generation layer. They were used as Samples 3 and 4 and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Example 3 A coating solution for forming an undercoat layer having the following composition was applied onto an aluminum cylinder by a dipping/ji coating method to form an undercoat layer having a film thickness of 0.5 after drying.

Polyvinylacetic acid represented by the following formula 25 parts by weight Aqueous solution of tar resin (s, c-113 wt%) f -5 (1 to 3
g, m-83 to 89, n-0,5-3,0 (all mol%) 1-Proper tool 75 parts by weight Next, the following ingredients were sand-grinded using a glass piece with a diameter of 1 mm as a media.・Dispersion treatment was carried out in a mill for 40 hours.

Granular trigonal selenium 87 parts by weight Vinyl chloride-vinyl acetate copolymer 13 parts by weight (Solution Vinyl VMCH, manufactured by Union Carbide) 3-pentanol 77 parts by weight Isobutyl acetate 123 parts by weight Obtained dispersion 30 parts by weight 57 parts by weight of n-butyl acetate was added to dilute the mixture to obtain a coating solution for forming a charge generation layer.

An electrophotographic photoreceptor was prepared in the same manner as Samples 1 and 2 of Example 1 using the obtained coating liquid for forming a charge generation layer. They were used as Samples 5 and 6 and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 1 In the same manner as in Example 1, a subbing layer was formed on the inner cylinder made of aluminum.

Next, the following components were dispersed for 40 hours in a sand grind mill using glass beads with a diameter of L mm as media.

Granular trigonal selenium 87 parts by weight Partially acetoacetalized poly 13 parts by weight Vinyl butyral resin (BX-1, manufactured by Sekisui Chemical ■) i-butanol 200 parts by weight For 30 parts by weight of the obtained dispersion, i-butanol A coating solution for forming a charge generation layer was obtained by adding 57 parts by weight to dilute the solution.

Using the obtained charge generation layer forming coating liquid, an electrophotographic photoreceptor was prepared in the same manner as Sample 1 of Example 1.

Using this as Sample 7, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 2 A subbing layer was formed on an aluminum cylinder in the same manner as in Example 3.

Next, the following components were dispersed for 40 hours in a sand grind mill using glass beads with a diameter of 1 rnrM as media.

Granular trigonal selenium 87 parts by weight Vinyl chloride-vinyl acetate copolymer 13 parts by weight (solution vinyl VMCH).

200 parts by weight of isobutyl acetate (manufactured by Union Carbide Co., Ltd.) To 30 parts by weight of the obtained dispersion, 57 parts by weight of isobutyl acetate was added and diluted to obtain a coating liquid for forming a charge generation layer.

Electrophotographic photoreceptors were prepared in the same manner as Samples 5 and 6 of Example 3 using the obtained coating liquid for forming a charge generation layer. They were used as Samples 8 and 9 and evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Margin below (Effects of the Invention) As mentioned above, since the coating liquid for forming a charge generation layer in the present invention uses a mixed organic solvent containing an alcohol having 4 or more carbon atoms, storage stability and manufacturing stability are improved. excellent,
It has a long pot life, and selenium particles or selenium alloy particles do not aggregate. Therefore, the method for producing an electrophotographic photoreceptor of the present invention using this coating liquid for forming a charge generation layer has excellent production stability, and the electrophotographic photoreceptor of the present invention thus formed has a high chargeability. It has high properties, low residual potential, and no white spots, black spots, roughness,
A copy image with clear and uniform density without image defects such as density unevenness and fogging can be obtained.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Charge transport layer, 2... Charge generation layer, 3... Subbing layer, 4... Conductive support. Figure 2

Claims (3)

[Claims] (1) In an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer laminated on a conductive support, the charge generation layer is an organic material containing an alcohol having 4 or more carbon atoms as part of the solvent component. An electrophotographic photoreceptor characterized in that the layer is formed by applying a coating liquid for forming a charge generation layer consisting of a solvent, selenium powder or selenium alloy powder, and a binder resin soluble in the organic solvent. . (2) In a method for producing an electrophotographic photoreceptor, which comprises coating a charge generation layer forming coating liquid and a charge transport layer forming coating liquid on a conductive support, the charge generating layer forming coating liquid comprises: An electronic device characterized by using a coating liquid consisting of an organic solvent containing an alcohol having 4 or more carbon atoms as part of the solvent component, selenium powder or selenium alloy powder, and a binder resin soluble in the organic solvent. A method for manufacturing a photographic photoreceptor. (3) The method for producing an electrophotographic photoreceptor according to claim 2, wherein the content of alcohol having 4 or more carbon atoms in the organic solvent is 5 to 90% by weight.