JP2000231206A - Production of electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high performance electrophotographic photoreceptor with a photosensitive layer uniform in thickness, free from curl, cracking, etc., having high planeness and capable of forming a uniform image. SOLUTION: When the top of an electrically conductive substrate comprising a flexible resin film with a laminated metallic layer is coated with a coating solution for forming a photosensitive layer by means of a die coater to produce an electrophotographic photoreceptor, the coating solution for forming a photosensitive layer is discharged from the outlet of an extended die slit through the constriction of the coating solution passage of a die discharge part to coat the top of the electrically conductive substrate with the coating solution. The width of the die slit is preferably expanded at an angle of 2-20 deg. to the discharge direction of the coating solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrophotographic photoreceptor for an electrophotographic apparatus, and more particularly, to a method of forming a photosensitive layer having a uniform thickness, having less occurrence of curls and cracks, and a method of producing a photosensitive layer having a flat surface. The present invention relates to a method for producing a high-performance electrophotographic photoreceptor capable of forming a uniform image with high image quality.

[0002]

2. Description of the Related Art In recent years, electrophotographic image forming methods have been widely used in copiers and printers in recent years, since high quality images can be obtained immediately. As a core photoconductor, a flexible electrophotographic photoconductor has attracted attention because it has a high degree of freedom when it is disposed in an apparatus.
Widely used. A flexible electrophotographic photosensitive member is used by forming a photosensitive layer such as a charge generation layer or a charge transport layer on a support in which a metal layer is formed on a flexible resin film.

The charge generating layer or the charge transporting layer is formed by applying a coating solution containing a charge generating agent or a charge transporting agent. The coating method is as follows. A highly uniform die coater is used. As shown in FIG. 5, the die coater has a manifold 2 extending in the width direction in a die 1 and a die slit 3 provided in series with the die, and a coating liquid discharged from the die slit 3 is coated on a support. Has been adopted.

When a coating solution for forming a photosensitive layer is applied to the support 4 using the die coater 1, both sides of the coating film 5 become thick as shown in FIG. If the photoreceptor is used in the form of a belt when the thick part occurs, the cause of cracks on the surface of the photosensitive layer when transported by being stretched by rollers,
This caused curling, which was a serious problem. In addition, when the photoreceptor obtained by coating and drying is rolled up on a roll, the thick portion is laminated, so that the rolled shape may have irregularities, causing the photoreceptor to wrinkle or bend. Was. Furthermore, such distortion of the surface of the photosensitive layer results in non-uniformity of the developing gap during use, causing a serious problem of uneven image density.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the photosensitive layer has a uniform thickness, has less occurrence of curls, cracks, and the like.
An object of the present invention is to provide a method for producing an electrophotographic photoreceptor capable of obtaining an electrophotographic photoreceptor capable of forming a uniform image with high planarity of a photosensitive layer.

[0006]

Means for Solving the Problems The present invention has been made as a result of diligent studies to achieve the above object, and has been described on a conductive support made of a flexible resin film on which a metal layer is laminated. In a method of manufacturing an electrophotographic photoreceptor in which a coating solution for forming a photosensitive layer is applied using a die coater, the coating solution for forming a photosensitive layer is widened through a narrowed portion in which a width of a coating solution flow path of a die discharge portion is reduced. A method for producing an electrophotographic photoreceptor, wherein the method is applied from a die slit outlet to a conductive support.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrophotographic photoreceptor of the present invention is formed by applying a coating material for forming a photosensitive layer to a metal layer of a conductive support in which a metal layer is laminated on a flexible resin film. As the material of the resin film constituting the conductive support, a resin having a high tensile strength and a small elongation or shrinkage is preferable. In general, polyester resins such as polyethylene terephthalate and polybutylene terephthalate are preferable, and polyethylene terephthalate is particularly preferable.

[0008] These resins are generally biaxially stretched after being formed into a film. The method of forming a film is not particularly limited, and it can be obtained by inflation molding or extrusion molding using a T-die.
The stretching method may be a sequential two-stage method in which the film is stretched in the lateral direction after the longitudinal stretching, or a biaxial simultaneous stretching method in which the film is stretched in the longitudinal direction and in the transverse direction at the same time. The thickness of the resin film is preferably 50 to 150 μm, more preferably 7 μm.
0 to 120 μm.

The metal constituting the conductive support includes:
Copper, nickel, aluminum and the like can be mentioned, but aluminum is preferred. Means for forming a metal layer on a resin film can be performed by a known method such as vacuum deposition, sputtering, chemical plating, and lamination. A photoconductor layer is formed on the conductive support on which the metal layer is laminated, but between the conductive support and the charge generation layer,
A commonly used barrier layer can be formed. As the barrier layer, nylon, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and the like can be used. Further, if necessary, inorganic particles such as titanium oxide and aluminum oxide may be contained.

A coating solution for a photosensitive layer is applied onto the conductive support thus obtained. The photosensitive layer may be a layer containing a charge generating substance and a charge transporting substance in a single layer, or may be a function-separated type in which a charge generating layer and a charge transporting layer are laminated. That is, a coating solution containing a charge generating substance and a charge transporting substance, specifically, in the case of a single-layer type photosensitive layer, the charge generating substance, the charge transporting substance, and a resin for binding the same are dissolved or dispersed in a solvent. The applied coating solution is applied, and in the case of the function separation type, a coating solution containing a charge generating substance and a coating liquid containing a charge transporting substance are prepared, and each is coated and laminated.

The function separation type will be described in more detail. The charge generation layer is formed by preparing a coating solution in which a charge generation material and a binder resin are dissolved or dispersed in a solvent, and coating the solution on a conductive support. . Examples of the charge generating substance include azo pigments such as Sudan Red, Diane Blue, and Genus Green B; disazo pigments; argon yellow; Examples thereof include benzoimidazole pigments, phthalocyanine pigments such as titanyl phthalocyanine and copper phthalocyanine, quinacridone pigments, pyrylium salts, and azurenium salts. The charge transport layer is applied on the charge generation layer by preparing a coating solution in which a charge transport material and a binder resin are dissolved or dispersed in a solvent.

As the charge transporting substance, for example, a skeleton of a polycyclic aromatic compound such as anthracene, phenanthrene, pyrene, coronene or the like, or indole, carbazole, imidazole, pyrazole, pyrazoline, triazole, Examples include compounds having a skeleton of a nitrogen-containing cyclic compound such as oxazole, isoxazole, oxadiazole, and thiazole, and hydrazone compounds.

The binder resin for forming the charge generation layer or the charge transport layer includes polycarbonate, linear polyester, polyacrylate, polystyrene, styrene-acrylate copolymer, styrene-acrylonitrile copolymer, polyacrylonitrile, and polysulfone. , Polyvinyl acetate, polyvinyl butyral, polyvinyl pyrrolidone, methyl cellulose, hydroxymethyl cellulose, cellulose ester, phenoxy resin, epoxy resin and the like.

Examples of the solvent for forming the coating solution include aromatic hydrocarbons such as benzene, toluene and xylene, alcohols such as methanol, ethanol and isopropanol, acetone, methyl ethyl ketone and 4-methoxy-4.
-Methyl-2-pentanone, 2,4-pentadione, 3
-Methyl oxobutanoate, ketones such as cyclohexanone, ethyl acetate, butyl acetate, esters such as methyl cellosolve acetate, dimethoxymethane,
Dimethoxyethane, methyl cellosolve, ethyl cellosolve, annealing, tetrahydrofuran, ether such as 1,4-dioxane, chloroform, dichloromethane,
Chlorinated hydrocarbons such as 1,2-dichloroethane and monochlorobenzene, nitrogen-containing compounds such as n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, N, N-dimethylformamide, N-methylpyrrolidone, dimethyl Aprotic polar solvent systems such as sulfoxide;

The solid concentration of the coating solution for the charge generation layer is 15
% By weight, preferably 1 to 10% by weight, and a viscosity of 0.1%
To 10 cps, and the thickness after drying is 0.1 to 1 μm. The solid content concentration of the coating solution for the charge transport layer is 40% by weight.
Hereinafter, preferably 10 to 35% by weight, and the viscosity is 30 to 30%.
The thickness after drying is 0 to 40 μm, preferably 12 to 30 μm.

In the present invention, a coating solution for forming a photosensitive layer, particularly a coating solution for forming a single-layer type photosensitive layer or a coating solution for forming a charge-separating layer of a function-separated type, is applied using the die coater of the present invention. You. In the die coater used in the present invention, a die having a narrowed portion in which the flow width of the coating liquid is narrowed is formed in the upstream portion on both sides of the die discharge portion, and a die having a die slit outlet wider than the narrowed portion is used. . The above-mentioned die discharge part means a part from the manifold to the die slit. As such a die coater, for example, a coater having a die shown in FIG. 1 can be used.

The die 1 shown in FIG. 1 has a manifold 2 and a die slit 3 connected to the manifold 2, and both ends of the die slit 3 upstream of the coating liquid narrow the flow path of the coating liquid. The constricted portion 3a formed as described above is provided, and the outlet 3b of the die slit 3 is formed such that the flow path of the coating liquid is widened. The die slit 3 can be formed into various shapes according to the purpose, and may be linearly widened from the constricted portion 3a toward the die slit outlet 3b as shown in FIG. As shown in FIG. 3B, a curved shape in which the receding angle increases toward the die slit outlet 3b may be used, or a curved shape in which the receding angle decreases toward the die slit outlet 3b as shown in FIG. 3C. FIG.
As shown in (D), the die slit outlet 3b may be formed in a bent line shape with a large receding angle. The size of the widening of the die slit 3 can be arbitrarily set according to the purpose, but generally, the inclination angle θ with respect to the outflow direction D of the coating liquid is 2 to 20 degrees. The overhanging die 1 may be formed integrally with a die having both sides of the die slit 3 having the above-described shape, or may be an assembling type as shown in FIG.

The die 1 shown in FIG. 2 is formed by dividing the die 1 into two halves 1a and 1b. The die 1 is provided with flow control plates 6, 6 on both sides of the die slit 3. Half body 1a
The die 1 of the present invention can be formed by tightening the dies 1b. By using the assembly type shown in FIG. 2, the degree of widening of the die slit 3 can be changed by replacing the flow path control plate 6, and the application liquid can be discharged by changing the position of the flow path control plate 6. The width can be changed.

The flow path control plate 6 does not need to be plate-shaped, but can be rod-shaped. As shown in FIG. By inserting the flow control rod 8, a constriction can be formed. In the present invention, since the coating liquid for forming the photosensitive layer is applied by using the die having the constricted portion as described above, the coating liquid discharged from the die becomes thin, so that when coated on the support 4 , And both sides of the photosensitive layer do not rise, so that a uniform photosensitive layer can be obtained.

[0020]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. Example 1 A 700-Å-thick aluminum vapor-deposited layer was formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness: 100 μm, width: 650 mm) to prepare a conductive support. The following coating liquid for a charge generation layer was applied to the aluminum-deposited surface of the obtained conductive support,
After drying at 50 ° C. to form a charge generation layer having a thickness of 0.5 μm, a charge transport layer shown below was die-coated under the following conditions.

As a charge generation material for a coating solution for a charge generation layer , the X-ray diffraction spectrum has a maximum diffraction peak at 27.3 ° at a Bragg angle (2θ ± 0.2 °) of 27.3 ° and 7.4 ° and 24.2 °. Using crystalline oxytitanium phthalocyanine showing a peak at a temperature of 10 ° C, 10 parts by weight of the oxytitanium phthalocyanine was added to 200 parts by weight of 4-methoxy-4-methyl-2-pentanone, followed by pulverization and dispersion treatment with a sand grind mill. The obtained dispersion was mixed with 100 parts by weight of a 5% by weight dimethoxyethane solution of polyvinyl butyral resin (“# 6000C” manufactured by Denka) and 100% by weight of a 100% by weight dimethoxyethane solution of phenoxy resin (“PHKK” manufactured by Union Carbide). A coating solution having a solid content concentration of 4% by weight in addition to the mixed solution of the coating solution and the mixture. The hydrazone compounds (A) and (B) having the following structure were used as the charge transporting material for the coating solution for the charge transporting layer .

[0022]

Embedded image

The compound (A) 56 parts by weight, (B) 14 parts by weight, and a polycarbonate resin (manufactured by Mitsubishi Chemical Corporation)
"NOVAREX 7030A") 100 parts by weight to 1,4-
A coating solution dissolved in 1000 parts by weight of dioxane. Ejection die die slit width (application width) 370 mm die slit depth 50mm die slit outlet widening angle 4-5 degrees coating speed 10 m / min coating film (dry) 17 .mu.m result, no dry layer uplink prime on either side of the photosensitive layer Obtained. Comparative Example 1 In Example 1, except that the die slit was not widened, and a die having the same width was used from the deep portion of the die slit to the outlet portion,
The same experiment as in Example 1 was performed. As a result, swelling of about 15% of the film thickness occurred on both sides of the photosensitive layer.

[Brief description of the drawings]

FIG. 1 shows a die used in the present invention, where (A) is a longitudinal front view and (B) is a longitudinal side view.

FIG. 2 is an exploded perspective view of another example of a die used in the present invention.

FIG. 3 is an exploded perspective view showing still another example of a die used in the present invention.

FIG. 4 is a partial longitudinal sectional view showing a shape of a die slit.

FIG. 5 shows a conventional die, in which (A) is a longitudinal sectional front view,
(B) is a longitudinal side view.

FIG. 6 is a longitudinal sectional view of a conventional electrophotographic photosensitive member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 2 Manifold 3 Die slit 3a Die slit constriction 3b Die slit outlet 4 Support 5 Photosensitive layer 6 Coating liquid flow control plate 7 Groove 8 Coating liquid flow control rod

Claims (7)

[Claims] 1. A method for manufacturing an electrophotographic photoreceptor, comprising applying a coating solution for forming a photosensitive layer on a conductive support made of a flexible resin film having a metal layer laminated thereon using a die coater. An electrophotographic photoreceptor characterized in that a coating liquid for forming is discharged from a die slit outlet widened through a narrowed portion of a coating liquid flow path of a die discharge portion and applied to a conductive support. Production method. 2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the die slit uses a die formed in a shape widened toward an exit. 3. The electrophotographic photoreceptor according to claim 1, wherein a die having a coating liquid flow control plate attached to both ends of the die slit so as to narrow the coating liquid flow path toward the upstream side of the coating liquid flow is used. Production method. 4. The electrophotographic photoreceptor according to claim 1, wherein a die formed so that a width of the die slit is widened at an angle of 2 to 20 degrees with respect to a discharge direction of the coating liquid. Manufacturing method. 5. The method of manufacturing an electrophotographic photosensitive member according to claim 1, wherein a die having a coating liquid flow control rod for narrowing a coating liquid flow path is mounted at both ends of the die slit. 6. The viscosity of the discharged coating liquid is 30 to 300.
The method for producing an electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is cps. 7. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the coating solution is a coating solution for forming a charge transport layer.