JP3166270B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

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 photoreceptor in which a coating for forming an electrophotographic photoreceptor is applied to a surface to be coated on a cylindrical support by an electrostatic spray coating method to form a coating film. About the method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an electrophotographic photosensitive member by forming a coating film on a cylindrical support using a coating material for forming an electrophotographic photosensitive member, a dip coating method, a spray coating method, a nozzle coating method, and the like. A method, a curtain coating method and a roll coating method are known. When the electrophotographic photoreceptor manufactured by these coating methods is used in a copying machine, a printer, or the like, both ends of the electrophotographic photoreceptor are used to maintain a constant gap between the curved surface of the electrophotographic photoreceptor and the developing unit. Replying to @Dragon The both ends for this roller are often uncoated. Therefore, it is desired that the boundary between the uncoated surface and the surface to be coated has no disturbance.

[0003] If the thickness of the film is disturbed at the end of the surface to be coated, the effective use range is narrowed, and it is necessary to increase the length of the electrophotographic photosensitive member, thereby increasing the cost. Miniaturization of copiers, printers, etc. is limited. Accordingly, it is desired to minimize the range of the nonuniformity of the film thickness at the end of the surface to be coated. In response to these demands, for example, in the widely used dip coating method, the non-coated surface of the upper portion of the electrophotographic photosensitive member can be relatively easily formed, but the lower portion is coated to the end, so that the solvent is required in a later step. In many cases, wiping is performed with a brush or tape attached with.

[0004] In addition, since the film thickness non-uniformity range at the end of the surface to be coated is relatively wide at the upper end, it is necessary to increase the length of the electrophotographic photoreceptor accordingly. There has been a problem that the ineffective length of the photoreceptor cannot be reduced. As for the nozzle coating method, as described in Japanese Patent Application Laid-Open No. 2-275463, a special and complicated method is used in order to manufacture a non-coated surface and to reduce the disorder of the film thickness at the end of the coated surface. There is a problem that a shielding member having a structure must be used.

Further, regarding the electrostatic spray coating method,
Japanese Patent Application Laid-Open No. Sho 62-6172 proposes a method in which a cylindrical support is held vertically and a coating film is formed by atomizing the coating material by a rotating plate. In addition, there is a problem that a wiping process is required in a subsequent step, and furthermore, there is a wide range of nonuniform film thickness due to liquid dripping at the end of the surface to be coated, particularly at the upper end.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to prepare an uncoated surface on the outer peripheral surfaces of both ends of a cylindrical support without wiping an electrophotographic photosensitive member in an electrostatic spray coating method. An electrophotographic photoreceptor capable of easily producing an electrophotographic photoreceptor in which the range of the uneven thickness portion at the end of the coated surface on the cylindrical support is small and the boundary between the coated surface and the non-coated surface is not disturbed. An object of the present invention is to provide a method for manufacturing a photoconductor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is to provide an electrophotographic photosensitive member-forming paint on a cylindrical support by an electrostatic spray coating method. In the method for producing an electrophotographic photoreceptor to be coated on the surface to be coated, a conductive paint shielding member having a thickness of 3 mm or less is provided on both ends of the cylindrical support, and the both ends of the cylindrical outer peripheral surface are 2 mm or less. The present invention provides a method for producing an electrophotographic photoreceptor, wherein coating is performed by arranging so as to cover the outer peripheral surfaces of the cylindrical portions at both ends in a non-contact state while maintaining a gap.

Hereinafter, the present invention will be described in detail. Examples of the electrostatic spray coating method in the present invention include International Publication W
A method and an apparatus for carrying out electrostatic spray coating by holding a cylindrical support horizontally and moving it at a constant speed while rotating as described in O89 / 05198 can be used. FIGS. 1 and 2 show examples of this coating apparatus. In the electrostatic spray coating method, droplets of paint for forming an electrophotographic photosensitive member are
In a charged state, it is electrically pulled and adhered to a cylindrical support, which is a conductor grounded from a spray head of the coating apparatus,
Based on the principle of forming a coating.

When coating is performed by disposing grounded conductive paint shielding members on both ends of the cylindrical support so as to cover the outer peripheral surfaces of the cylindrical portions at the both ends, the liquid droplets are similarly electrically To adhere to the paint shielding member. Normal,
The paint shielding members are provided as separate members at both ends of the cylindrical support. At this time, if the gap between the paint shielding member and the end cylindrical outer peripheral surface of the cylindrical support is 2 mm or less,
At the time of coating, no lines of electric force are generated in this gap, and droplets containing the coating material for forming an electrophotographic photoreceptor do not enter this gap. Therefore, the coated surface of the cylindrical support and the uncoated surface of the end are not coated. An electrophotographic photoreceptor having no disturbance at the boundary can be produced.

If the gap is larger than 2 mm, a part of the liquid droplets enters the gap and adheres to the portion of the cylindrical support which should be the non-coated surface, and the liquid is applied to the surface to be coated. An electrophotographic photoreceptor in which the boundaries of the coating surface are disturbed will result. Here, the gap between the paint shielding member and the outer peripheral surface of the cylindrical end portion of the cylindrical support is a part of the paint shielding member, a portion covering the cylindrical support, particularly within several tens mm from the end of the portion. It refers to the distance between the paint shielding member and the end cylindrical outer peripheral surface of the cylindrical support in the range.

If the paint shielding member is in contact with the outer peripheral surface of the cylindrical end portion of the cylindrical support, the cylindrical support may be damaged or stained. It is necessary to be in a non-contact state because it reduces the value. At the time of electrostatic spray coating, it is necessary that the paint shielding member be conductive in order to reduce the range of the portion having an uneven thickness at the end of the coating surface on the cylindrical support. As the material of the paint shielding member, for example, a metal material such as aluminum, stainless steel, copper, and nickel, and a material in which fine powder such as aluminum, copper, tin oxide, and indium oxide are dispersed in a binder to make the material conductive may be used. it can.

In the case where the paint shielding member is an insulating material such as Teflon, for example, the droplets that should originally adhere to the shielding member receive an electric repulsion and adhere extra to the end of the surface to be coated. , While the end of the surface to be coated has a raised shape,
The range of the portion where the film thickness is not uniform becomes wider. Further, in order to reduce the range of the portion where the film thickness is not uniform at the end of the coating surface on the cylindrical support, the thickness of the paint shielding member needs to be 3 mm or less.

In order to further reduce the range of the uneven thickness portion, the thickness of the paint shielding member is preferably 2 mm or less, more preferably 1 mm or less, and the rigidity required for the paint shielding member is not more than 1 mm. Any thickness may be used as long as it can have When the thickness of the paint shielding member exceeds 3 mm, the droplet containing the paint which should be originally attached near the end of the coating surface adheres to the paint shielding member, and the range of the thin portion is preferably wide. Absent.

Here, the thickness of the paint shielding member refers to a portion of the shielding member which covers the outer peripheral surface of the end of the cylindrical support, particularly a thickness within a range of several tens of cm from the end of the shielding portion. . The shape of the paint shielding member is such that a part of the member is the outer peripheral surface of the cylindrical end portion of the cylindrical support and the surface to be an uncoated surface is 2 mm.
What is necessary is just to be able to maintain a non-contact state with the following gaps, for example, a cylindrical shape indicated by 16 in FIG.

In FIG. 3, the paint shielding member 16 is fixed to the flange 3. Usually, the fixing to the flange is preferably performed by a detachable fixing method, and is performed using a bolt or the like. FIG. 5 shows another example of the shape of the paint shielding member in the present invention.
7 to FIG. In the example of the paint shielding member shown in FIG. 5, the thickness 22 of the paint shielding member at the portion fixed to the flange 3 is within a range of several tens mm from the end of the portion covering the cylindrical support. 23, which is a preferable shape for fixing the member to the flange.

In the example of the paint shielding member shown in FIGS. 6 and 7, the paint shielding member is in contact with the side surface 24 and the like of the flange 3 and can be fixed with a bolt or the like at this side portion. As shown in FIG. 3, the flange 3 is a cylindrical support 2
And is held by the shaft 1 and the pusher 17. FIG. 3 shows only one end of both ends of the cylindrical support, and the other end (not shown) can be shielded in the same manner. FIG. 4 is an enlarged view of a portion indicated by 18 in FIG. FIG.
Here, a coating film 19 is shown on the cylindrical support 2. In the example of the paint shielding member in FIG. 4, the thickness of the paint shielding member is indicated by 20, and the gap between the paint shielding member and the outer peripheral surface of the end cylinder of the cylindrical support is indicated by 21.

As the cylindrical support in the present invention, a metal material such as aluminum, stainless steel, copper and nickel, and a fine powder such as aluminum, copper, tin oxide and indium oxide are dispersed in a binder to form a conductive layer. Aluminum, copper, palladium, tin oxide, indium oxide, or the like, which has been deposited on a polyester film or the like.

The coating material for forming an electrophotographic photosensitive member according to the present invention includes a coating solution containing a charge generating material and / or a charge transport material, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, allulose, gelatin, starch, and the like. A coating solution containing a polymer such as polyurethane, polyimide, and polyamide, or a coating solution in which a conductive fine powder is dispersed in these polymers, and the like can be given.

The charge generating materials include (1) azo pigments (2) perylene pigments (3) anthraquinone pigments or polycyclic quinone pigments (4) indigoid pigments (5) phthalocyanine pigments (6) carbonium pigments Pigment (7) Quinone imine pigment (8) Methine pigment (9) Quinoline pigment (10) Nitro pigment (11) Nitroso pigment (12) Benzoquinone and naphthoquinone pigment (13) Naphthalimide pigment (14) Bisbenz Known charge generating agents such as imidazole derivatives are exemplified.

As the charge transporting material, an electron transporting medium or a hole transporting medium can be used, and a mixture thereof can also be used. As an electron transport medium, an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group or an ester group, for example, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone and the like And nitrated fluorenone or tetracyanodimethane. Further, as a hole transport medium, an electron-donating organic photoconductive compound such as carbazole,
Heterocyclic compounds such as indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole; triarylalkane derivatives such as triphenylmethane; triarylamine derivatives such as triphenylamine; phenylenediamine derivatives; N-phenyl Carbazole derivatives; stilbene derivatives; hydrazone compounds and the like.

As a medium for preparing the coating solution, N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, 4-methoxy-4-
Methylpentanone-2, dimethoxymethane, benzene,
Toluene, dimethoxyethane, xylene, chloroform, 1,2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, 2,4 pentanedione, methyl 3-oxobutanoate, and the like. .

The charge generating material and / or the charge transporting material may be dispersed alone in the dispersion medium or together with a suitable binder resin to form a coating solution. In addition, the coating solution may be a dispersant, another binder resin, another Organic solvents, antioxidants,
It may contain a sensitivity deterioration preventing material, a leveling material, and various other known additives. The solid content in the coating solution is determined mainly according to the thickness of the layer to be formed. When a charge generation layer of a stacked type is formed, the solid content concentration is 10% by weight or less, more preferably 0%. It is good to be 0.5-5% by weight. In the case of forming a stacked type charge transport layer or a single layer type photosensitive layer containing a charge generating material and a charge transport material, it is necessary to form a thicker photosensitive layer.
The content is preferably 0% by weight or less, more preferably 10 to 35% by weight.

The thickness of the stack type charge generation layer is usually 0.05
The range from μm to 5 μm, preferably from 0.1 μm to 2 μm is suitable. The thickness of the layered charge transport layer is usually 5 μm to 80 μm, preferably 10 μm to 60 μm. The thickness of the single-layer type photosensitive layer is usually 5 μm to 80 μm.
m, preferably 10 μm to 60 μm. In the case of forming a polymer layer or a polymer layer in which conductive fine powder is dispersed, the solid content concentration is preferably 45% by weight or less, more preferably 1 to 35% by weight. The thickness of the polymer layer or the polymer layer in which the conductive fine powder is dispersed is usually 0.1 μm to 100 μm, preferably 0.2 μm to 80 μm.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

Example 1 A charge generating layer of a laminated type was applied and formed as follows. As a coating solution containing charge generation materials

[0026]

TABLE 1 Azo compound represented by the following structural formula (1) 2 parts Polyvinyl butyral resin represented by the following structural formula (2) 1 part Phenoxy resin represented by the following structural formula (3) 1 part 4-methoxy-4-methyl Pentanone-2 316 parts was dispersed and mixed and dissolved by a sand grinder mill to obtain a coating liquid having a viscosity of 1.5 centipoise.

The cylindrical support has an outer diameter of 80 mm and a length of 34.
After washing with a commercially available 4-tank ultrasonic cleaner using trichlorethylene using an aluminum cutting tube of 8 mm and a wall thickness of 1 mm, it is rotated and moved under the spray head in the transport system shown in FIGS. 1 and 2. The above coating solution is sprayed from a spray head (a 2 inch grooved minibell type with a J4 turbo motor manufactured by Randsburg Japan Co., Ltd.) onto a cylindrical support, and a dry coating film thickness of 0.4 μm is obtained in 20 seconds per tube. Was applied as follows.

The length of the uncoated surface was 12 mm, the thickness of the paint shielding member was 1 mm using aluminum, and the gap with the cylindrical support was 1 mm. After the application, the film was dried at a heater temperature of 250 ° C. for 3 minutes by a far-infrared drier while rotating.
As a result, the boundary between the coated surface and the non-coated surface was clear without any disturbance, and the film thickness of the coated surface was kept uniform up to the boundary.

Comparative Example 1 The procedure of Example 1 was the same except that the gap between the paint shielding member and the cylindrical support was 3 mm. As a result, the boundary line between the coated surface and the non-coated surface was not clear, and the paint was stuck in places where the non-coated surface should be.

Example 2 A laminate type charge transport layer was applied and formed as follows. As coating solution containing charge transport material

[0031]

TABLE 2 110 parts of hydrazone compound represented by the following structural formula (4) 100 parts of polycarbonate resin represented by the following structural formula (5) 1.5 parts of acceptor represented by the following structural formula (6) 1.5 parts of the following structural formula (7) 2 parts antioxidant represented by the following structural formula (8) 0.03 parts Charge control agent represented by the following structural formula (9) 0.2 part 2-4 pentanedione 450 parts 3-oxobutanoic acid 230 parts of methyl and 80 parts of tetrahydrofuran were mixed and dissolved to obtain a coating liquid having a viscosity of 100 centipoise.

The same coating machine as in Example 1 was obtained by using the above coating solution on the cylindrical support having the charge generation layer obtained in Example 1,
Coating was performed with a carrier machine (at the same processing speed) so that the length of the uncoated surface was 12 mm and the thickness of the dried coating film was 20 μm. Here, the shielding member is made of aluminum and the thickness is 1 mm, 2 mm, 3 mm, 4 mm.
The gap between the shielding member and the cylindrical support was 1 mm.

Drying was carried out using a far-infrared dryer in the same manner as in Example 1 at a heater temperature of 220 ° C. for 15 minutes. The coating experiment was performed twice for each thickness. As a result, FIG. 8 shows the relationship between the thickness of the paint shielding member and the length of the non-uniform film thickness portion at the end of the coating surface. In each case, the boundary between the coated surface and the non-coated surface was clear without any disturbance. From FIG. 8, it can be said that the thickness of the shielding member is preferably 3 mm or less in order to shorten the length of the non-uniform film thickness portion at the end of the coating surface.

Comparative Example 2 The procedure of Example 2 was repeated except that Teflon, an insulating material, having a thickness of 1 mm was used as the shielding member, and the thickness of the dried coating film was 23 μm. In this case, although the boundary between the coated surface and the non-coated surface was not disturbed, the film thickness at the end of the coated surface was raised, which was a problem as an electrophotographic photosensitive member.

Example 3 A single-layer type photosensitive layer containing a charge generating material and a charge transporting material was applied and formed as follows. As a coating solution containing a charge generation material and a charge transport material

[0036]

Table 3 100 parts of a hydrazone compound represented by the following structural formula (4) 100 parts of a polycarbonate resin represented by the following structural formula (10) 4 parts of an antioxidant represented by the following structural formula (7) 4 parts The following structural formula (8) 0.03 parts of a leveling agent represented by the formula: 760 parts of cyclohexanone dissolved in 10 parts of an azo compound represented by the following structural formula (11), 360 parts of cyclohexanone were mixed, and a liquid obtained by dispersion treatment with a sand grinder mill was mixed. A coating liquid having a viscosity of centipoise was obtained.

The thickness of the dried coating is adjusted to 20 μm,
The drying condition was a heater temperature of 220 ° C with a far-infrared dryer.
Coating was performed in the same manner as in Example 1 except that the coating time was 5 minutes. The results were clear without any disturbance of the boundary between the coated surface and the non-coated surface, and the film thickness distribution at the end of the coated surface was also good.

[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

As described above, according to the method of manufacturing an electrophotographic photoreceptor of the present invention, the range of the nonuniform film thickness at the end of the coated surface of the cylindrical support is small, By obtaining an electrophotographic photoreceptor with no disturbance at the boundary with the coating surface, the ineffective length of the electrophotographic photoreceptor can be shortened, cost can be reduced, and a copying machine equipped with the electrophotographic photoreceptor can be used. It is possible to make the machine body such as a laser printer more compact. In addition, since the end wiping operation in the next step after the application is not required, there is no defect related to the wiping or a product defect due to the splash of the wiping liquid.
Cost reductions in equipment and yield can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of a coating apparatus.

2A is an explanatory front view of a part of FIG. 1; FIG. 2B is an explanatory cross-sectional view taken along a line II ′ in FIG. 1;

FIG. 3 is an explanatory cross-sectional view showing an example of a paint shielding member and a part of a coating apparatus using the paint shielding member.

FIG. 4 is an enlarged view of a part of FIG. 3;

FIG. 5 is an explanatory cross-sectional view of a paint shielding member and a flange showing an example of a paint shielding member.

FIG. 6 is an explanatory cross-sectional view of a paint shielding member and a flange showing an example of a paint shielding member.

FIG. 7 is an explanatory cross-sectional view of a paint shielding member and a flange showing an example of a paint shielding member.

FIG. 8 is a diagram showing the relationship between the range of a portion having an uneven thickness and the thickness of a paint shielding member.

[Explanation of symbols]

1 Shaft 2 cylindrical support 3 flanges 4, 5, 6, 7 supporting and rotating rollers 8 pusher (P ₁₎ 9, 10 pusher (P ₂₎ 11, 12 the pusher (P ₃₎ 13, 14 loading shaft 15 spray head Reference Signs List 16 paint shielding member 17 pusher 18 enlarged portion in FIG. 2 19 coating film 20 thickness of paint shielding member 21 gap between cylindrical support and paint shielding member 22 thickness of paint shielding member fixed to flange 23 The thickness of the paint shielding member within a range of several tens of millimeters from the end of the portion covering the cylindrical support.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/05 102

Claims (1)

(57) [Claims] 1. A method for producing an electrophotographic photoreceptor in which a coating for forming an electrophotographic photoreceptor is applied to a surface to be coated on a cylindrical support by an electrostatic spray coating method. A paint shielding member is disposed at both ends of the cylindrical support so as to cover the outer peripheral surfaces of the both end cylinders in a non-contact state in which a gap of 2 mm or less is maintained between the outer peripheral surfaces of the both end cylinders. A method for producing an electrophotographic photoreceptor.