JP2003270804A - Method for manufacturing electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously form a stable coating film uniform in film thickness on a plurality of substrates for electrophotographic photoreceptors and to provide an electrophotographic photoreceptor having good image characteristics and an image forming apparatus giving good images. <P>SOLUTION: The method for manufacturing electrophotographic photoreceptors in which a coating film is formed on substrates for electrophotographic photoreceptors by a dip coating method, is characterized in that the film thickness distribution of a coating film is measured after coating and before drying and coating conditions are set according to the measurements to control the film thickness distribution of a coating film. <P>COPYRIGHT: (C)2003,JPO

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 photosensitive member, and more particularly to a method for manufacturing an electrophotographic photosensitive member in which a coating film is formed on a substrate for an electrophotographic photosensitive member by a dip coating method, and the manufacturing method. The present invention relates to an electrophotographic photosensitive member manufactured by and an image forming apparatus using the photosensitive member.

[0002]

2. Description of the Related Art Electrophotographic technology has been widely used not only in the field of copying machines but also in the fields of laser beam printers and facsimiles in recent years because it can provide images with instantness, high quality and high storability. Has been done. This electrophotographic process basically involves uniform charging of the electrophotographic photosensitive member, formation of an electrostatic latent image by image exposure, development of the latent image with toner, transfer of the toner image onto paper (transferring the intermediate transfer member). It may also go through) and the image forming process by fixing.

The electrophotographic photosensitive member is manufactured by forming a coating film such as an undercoat layer or a photosensitive layer on a substrate for an electrophotographic photosensitive member (hereinafter appropriately referred to as a substrate). When an undercoat layer is formed on the substrate, polyvinyl alcohol, casein, sodium caseinate, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used as the undercoat layer. ing. As the photosensitive layer formed on the blocking layer such as the undercoat layer, an inorganic material or an organic material of a photoconductive material is used. The organic material is used by dispersing or dissolving a photoconductive material in an organic solvent, and is widely used as a photosensitive layer because of its low toxicity, low cost and high degree of freedom in material design.

Examples of the coating method of the coating film include a dip coating method, a spray coating method, a spinner coating method, a blade coating method, a bar coat coating method, a roll coat coating method and a ring coating method. The dip coating method is often used because of high productivity. The dip coating method is a method in which a container containing a coating solution and a photoconductor substrate are moved relative to each other to immerse the substrate in the coating solution, and then the substrate is pulled up, and then the substrate thus pulled up is allowed to stand and naturally dried. In order to produce an electrophotographic photosensitive member having a coating film having a uniform thickness in the vertical direction of the substrate, a solvent that is a quick-drying solvent is usually used as the solvent for the coating liquid.

[0005]

However, in the dip coating method, when the substrate is pulled up, the coating film sags due to gravity, so that the film thickness at the upper end side in the pulling direction becomes thin,
Furthermore, the lower end side of the pulled-up coating film in the pulling direction is
There is a problem in that the coating film drips from above, resulting in non-uniformity of the film thickness distribution such that the film thickness increases.

Further, the solvent concentration of the coating liquid changes as the solvent evaporates from the coating liquid. When the solvent concentration changes, the solvent evaporation rate of the coating film also changes, and the film thickness distribution becomes more non-uniform. Further, even if the solvent concentration of the coating liquid is constant, such evaporation rate locally changes depending on the liquid temperature, room temperature, air volume, and substrate temperature. As described above, there are many factors that control the film thickness distribution, and by controlling all of these fluctuation factors, a photosensitive layer, that is, a photosensitive member having a uniform photosensitive property with a uniform film thickness on a plurality of substrates can be obtained. It was very difficult to get.

The coating film is dried after coating to remove the residual solvent in the coating film, but rapid drying causes foaming of the coating film and renders it unusable. Therefore, the coating film is gradually dried over a long period of time. Therefore, from the viewpoint of productivity, many photoconductors are produced during such a long time, and when the film thickness distribution of the photosensitive layer is measured after drying and a nonuniform film thickness distribution is found, There has been a problem that all the photoconductors having the photoconductive layer formed under the same conditions are defective photoconductors with uneven thickness distribution. That is, in order to obtain a good photoconductor with good productivity, it was desired to be able to estimate and control the film thickness distribution before drying the photosensitive layer.

In Japanese Patent Laid-Open No. 2001-27815,
When applying the coating liquid on the substrate by the dip coating method, the wet film thickness is measured before heating and drying, the dry film thickness and the like are estimated based on the measured wet film thickness, and the coating conditions are estimated from the results. There is. However, although the invention described in the publication describes that the thickness of the film is predetermined and uniform, in reality, only the thickness of the film is focused on, and the problem of nonuniformity of the film thickness distribution is solved. Since no point is mentioned, it is not possible to obtain a good photoconductor having a uniform film thickness distribution. Furthermore,
As the coating conditions obtained in the invention described in this publication, since attention is paid only to the thickness of the film thickness, only information about the temperature of the coating liquid and the coating speed is obtained, and a photoconductor having a uniform film thickness distribution. Couldn't get

[0009]

Therefore, the inventors of the present invention have made diligent studies and found that in the method for producing an electrophotographic photosensitive member, the coating film is formed on the substrate for electrophotographic photosensitive member by the dip coating method. By measuring the film thickness distribution of the coating film after coating and before heating and drying, and by setting the coating conditions based on the measurement results, by controlling the film thickness distribution of the coating film,
It was found that the above problems could be solved, and the present invention was reached. According to the present invention, it is possible to set appropriate coating conditions for obtaining a coating film having a uniform film thickness distribution, and as a result, it is possible to obtain a good photoreceptor.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the method for producing an electrophotographic photosensitive member of the present invention, a coating film is formed on a substrate for an electrophotographic photosensitive member by a dip coating method. The substrate is not particularly limited as long as it is used as a substrate for an electrophotographic photoreceptor, but specifically, aluminum or an aluminum alloy, a metal material such as stainless steel, copper or nickel, and aluminum on the surface thereof. Insulating substrates such as polyester film, paper and glass provided with a conductive layer such as copper, palladium, tin oxide and indium oxide are used. When a non-conductor is used, it is generally conducted by blending a conductive powder or by conducting metal deposition on the surface. A substrate made of aluminum or aluminum alloy is preferable. The shape of the substrate is not particularly limited, but a cylindrical substrate is generally used. In addition, the substrate may be finished to have a specific surface roughness by using a cutting process. The case where cylindrical aluminum is used as the substrate will be described below.

The coating film is not limited as long as it can be coated on the substrate by the dip coating method, and examples thereof include an undercoat layer and a photosensitive layer. In the case of a laminated type photosensitive layer, the applied photosensitive layer is divided into a charge generation layer, a charge transport layer and the like. As the undercoat layer, polyvinyl alcohol,
Organic layers such as casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide and polyamide can be used.
Among them, a polyamide resin having excellent adhesiveness to the substrate and having low solubility in the solvent used in the charge generation layer coating solution is preferable. It is effective to incorporate fine particles of metal oxides such as alumina and titania and organic or inorganic pigments into the undercoat layer. The thickness of the undercoat layer is usually 0.1 to 1
It is 0 μm, preferably 0.2 to 8 μm.

As the photosensitive layer, a charge generating layer containing a charge generating substance and a charge transporting layer are laminated in this order, an opposite layer is laminated, or a so-called single layer type in which charge generating substance particles are dispersed in a charge transporting medium. Although any of the above can be used, a laminated photosensitive layer having a charge generation layer and a charge transport layer is preferable. When the photosensitive layer has a single-layer structure, a known material in which a photosensitive material is dispersed in a binder material is used.
For example, a dye-sensitized ZnO photosensitive layer, CdS photosensitive layer,
Examples thereof include a photosensitive layer in which a charge generating substance is dispersed in a charge transporting substance.

A method for forming a uniform coating film on the above-mentioned substrate by a dip coating method is, for example, JP-A-7-20646.
The publication discloses a method of using a shield. After the coating film is formed, the photoreceptor is usually completed through steps such as heating and drying.

In the present invention, the film thickness distribution of the substrate having the coating film is measured after the coating and before the drying by heating. By measuring the coating film before drying, it is possible to solve the above problems and efficiently produce a large number of photoreceptors. Since the change in film thickness due to the evaporation of the solvent is very severe for about 2 minutes immediately after the application, it is preferable to perform the measurement 10 minutes after the application, where the change in the film thickness becomes slow. In order to measure the film thickness distribution accurately, it is important to measure the circumferential direction and the axial direction of the substrate having the coating film. The film thickness distribution is measured by JP-A-2001-2781.
The optical interference method disclosed in Japanese Patent No. 5 is used.

From the measurement results, the coating conditions for obtaining a photoconductor having a uniform film thickness distribution are set. For example, if the thickness of the coating film on the upper end of the substrate pulled up during dip coating is relatively thin as compared to the central part, the method disclosed in JP-A-59-80364, that is, the upper end Perform the operation of overpainting only. Alternatively, the method disclosed in Japanese Patent Application Laid-Open No. 10-26835, that is, the pulling-up operation is performed at a distance from the upper end to 30 mm in a plurality of speed ranges of a pulling speed or more for forming a constant film thickness. Alternatively,
Make a difference between the coating speed at the top of the coating and the coating speed at the center. By setting such conditions, a uniform film thickness distribution can be obtained.

Further, for example, if the thickness of the coating film at the lower end of the substrate is relatively thick, the shield used at the time of coating extends the time period for surrounding the substrate having the coating film, so that the coating film at the lower end can be extended. A coated film having a uniform film thickness distribution up to the lower end is obtained (Japanese Patent Laid-Open No. 7-20646). Conversely,
If the thickness of the coating film at the lower end of the substrate is relatively thin, the time for surrounding the substrate with a shield is shortened, the sagging of the coating film at the lower end is suppressed, and the coating having a uniform film thickness distribution up to the lower end. Get the membrane. As described above, the natural drying in the solvent vapor can be controlled by adjusting the time for surrounding the substrate with the shield.

By preliminarily determining the relationship between the film thickness distribution shape, the conditions of multi-step coating at the upper end and the conditions such as the time for surrounding the substrate with a shield, etc. off-line, it is possible to obtain the relationship immediately after coating as described above. By measuring the wet film thickness distribution, it is possible to rapidly change the conditions such as the multi-step coating on the upper end portion and the time for surrounding the substrate with a shield. As a result, changes in the film thickness distribution can be sensed promptly and the coating conditions can be changed, so that the occurrence of defective photoconductors can be minimized. Actually, by continuously measuring the film thickness distribution after coating and before drying, the conditions can be appropriately changed in response to the change in the film thickness distribution.

Before the photosensitive layer is formed on the substrate, a blocking layer such as the undercoat layer or the anodized film may be formed. An undercoat layer can be formed on the anodic oxide coating. When forming the anodized film, it is preferable to perform degreasing treatment by various degreasing cleaning methods such as acid, alkali, organic solvent, surfactant, emulsion, electrolysis, etc. before anodizing treatment. The anodized film is formed by a conventional method, for example, chromic acid, sulfuric acid, oxalic acid, boric acid,
It is formed by anodizing in an acidic bath such as sulfamic acid, but anodizing in sulfuric acid gives the best results. In the case of anodizing treatment in sulfuric acid,
Sulfuric acid concentration is 100 to 300 g / l, dissolved aluminum concentration is 2 to 15 g / l, liquid temperature is 0 to 30 ° C., electrolysis voltage is 1
It is preferable that the current density is set to 0 to 20 V and the current density is set to 0.5 to ² A / dm ² , but the present invention is not limited to this. The thickness of the anodized film thus formed is usually 20 μm or less, preferably 10 μm.
m or less, more preferably 7 μm or less.

The anodized substrate can be subjected to sealing treatment or dyeing treatment. The sealing treatment is a step of sealing by growing aluminum hydroxide or the like in the porous layer. The sealing treatment method may be an ordinary method, for example, a liquid containing nickel ions (for example, a liquid containing nickel acetate,
It is preferably dipped in a solution containing nickel fluoride). Further, when the dyeing treatment is performed, the substrate is immersed in a salt solution of an organic or inorganic compound to adsorb those salts. Specifically, 1 to 10 g / l of a water-soluble organic dye such as azo,
The liquid temperature is 20 to 60 ° C., the pH is 3 to 9, and the immersion time is 1 to 20 minutes.

The photosensitive layer is formed as it is on the substrate on which the blocking layer is formed or on the substrate. Examples of the photosensitive layer include the types described above, and the laminated type photosensitive layer will be described below. The charge generation layer contains a charge generation substance and a binder resin. The charge generating substance is not particularly limited as long as it is a substance used for an electrophotographic photoreceptor, and specifically, selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, and other inorganic photoconductors. Organic pigments such as phthalocyanine, azo, quinacridone, polycyclic quinone, perylene, indigo, and benzimidazole can be used. In particular, copper, indium chloride, potassium chloride, tin, oxytitanium, zinc, phthalocyanine pigments such as vanadium, or its oxide or chloride coordinated phthalocyanines, such as metal-free phthalocyanines, or monoazo, bisazo, Examples include azo pigments such as trisazo and tetrakisazos. Of these, azo pigments and oxytitanium phthalocyanine are particularly preferable.

The solvent or dispersion medium for preparing the coating liquid is not particularly limited as long as it is used in the manufacturing process of the electrophotographic photosensitive member, and various solvents may be used. For example, ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,2-dimethoxyethane; ketones such as acetone, methyl ethyl ketone, cyclohexanone; esters such as methyl acetate, ethyl acetate; alcohols such as methanol, ethanol, propanol, etc. And aromatic hydrocarbons such as toluene and xylene, and the like, and these may be used alone or in combination of two or more. When the charge generating substance is dispersed in the solvent, the amount of the dispersion medium to be used may be any amount as long as the dispersion can be sufficiently performed and an effective amount of the charge generating substance is contained in the dispersion liquid. The concentration of the charge generating substance in the dispersion is preferably 3 to 20 wt%, more preferably 4 to 20 wt%.

The binder resin is not particularly limited as long as it is used for an electrophotographic photoreceptor, but specifically, polyvinyl butyral, polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone. , Vinyl polymers such as polyimide, polymethylmethacrylate, and polyvinyl chloride, and their copolymers, phenoxy, epoxy, silicone resins and the like, and partially cross-linked cured products thereof can be used alone or in combination of two or more. As a method of mixing the binder resin and the charge generating substance, for example,
The charge generation material is dispersed in the binder resin powder in the dispersion treatment step, or the polymer solution is added and dispersed at the same time, the dispersion obtained in the dispersion treatment step is mixed with the polymer solution of the binder resin, or conversely dispersed. Any method such as a method of mixing the polymer solution in the liquid may be used.

Next, the dispersion liquid obtained here may be diluted with various solvents in order to make the liquid properties suitable for coating. As such a solvent, for example, the solvents exemplified as the dispersion medium can be used. The ratio of the charge generating substance to the binder resin is not particularly limited, but generally the charge generating substance is used in the range of 5 to 500 parts by weight with respect to 100 parts by weight of the resin. If necessary, a charge transport material can be included. Examples of the charge transport material include organic polymer compounds such as polyvinylcarbazole, polyvinylpyrene, and polyacenaphthylene,
Electron-withdrawing substances such as fluorenone derivatives, tetracyanoquinodimethane, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives,
Heterocyclic compounds such as carbazole, indole, imidazole, oxazole, pyrazole, oxadiazole, pyrazoline, and thiadiazole, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, or groups consisting of these compounds in the main chain or side chain. And electron-donating substances such as polymers.
The ratio of the charge transport material to the binder resin is 5 to 500 parts by weight based on 100 parts by weight of the binder resin.

Using the dispersion liquid thus prepared,
A charge generation layer is formed on the substrate after cutting or on a substrate on which a blocking layer such as an undercoat layer or an anodized film is formed, and a charge transport layer is laminated thereon to form a photosensitive layer, or A charge transport layer is formed on a substrate, and a charge generating layer is formed on the charge transport layer using the dispersion liquid to form a photosensitive layer;
Alternatively, the photosensitive layer can be formed with any structure in which a charge generating layer is formed on the substrate using the dispersion liquid to form a photosensitive layer. The thickness of the charge generation layer is preferably in the range of 0.1 to 10 μm when the photosensitive layer is laminated with the charge transport layer, and the thickness of the charge transport layer is preferably 10 to 40 μm. When the photosensitive layer is formed with a single layer structure, the thickness of the photosensitive layer is preferably in the range of 5 to 40 μm.

The charge transport layer has excellent performance as a binder resin on the charge generation layer, or on a substrate after cutting or on a substrate on which a blocking layer such as an undercoat layer or an anodized film is formed. Coating with a coating solution obtained by mixing with a known polymer having a solvent and dissolving it in a suitable solvent together with a charge-transporting substance, and optionally adding an electron-withdrawing compound, or a plasticizer, a pigment and other additives. By doing so, it can be manufactured.

As the charge-transporting substance in the charge-transporting layer, the above-mentioned charge-transporting substances can be used. As the binder resin used together with the charge transport material, various known resins can be used. Thermoplastic resins and curable resins such as polycarbonate resins, polyester resins, polyarylate resins, acrylic resins, methacrylate resins, styrene resins, and silicone resins can be used. Particularly preferred are polycarbonate resins, polyarylate resins, and polyester resins, which are less likely to cause wear and scratches. As the bisphenol component of the polycarbonate resin, bisphenol A, bisphenol C, bisphenol P, bisphenol Z, or various known components can be used. It may also be a copolymer of these components. The compounding ratio of the charge transport material and the binder resin is, for example, 10 to 200 parts by weight, preferably 30 to 150 parts by weight, based on 100 parts by weight of the binder resin. In the case of a laminated type photosensitive layer, the charge transporting layer is formed by using the above components as main components.

Solvents used for the charge transport layer coating liquid include tetrahydrofuran, 1,4-dioxane, 1,2.
-Ethers such as dimethoxyethane and anisole; ketones such as methyl ethyl ketone, 2,4-pentanedione and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate, methyl formate and dimethyl malonate; 3 Ether ethers such as methoxybutyl acetate and propylene glycol methyl ether acetate; and chlorinated hydrocarbons such as dichloromethane and dichloroethane. Of course, one kind or two or more kinds may be selected from these and used. Preferably, tetrahydrofuran, 1,4-dioxane, 2,4
-Pentanedione, anisole, toluene, dimethyl malonate, 3-methoxybutyl acetate, propylene glycol methyl ether acetate are preferred.

Further, the photosensitive layer of the electrophotographic photosensitive member of the present invention is a well-known plasticizer, antioxidant, ultraviolet absorber, leveling agent in order to improve film-forming property, flexibility, coating property and mechanical strength. May be contained. Further, an overcoat layer may be provided on the photosensitive layer in order to improve mechanical characteristics and gas resistance characteristics such as ozone and NOx. Needless to say, it may have an adhesive layer, an intermediate layer, a transparent insulating layer, and the like, if necessary.

Examples of the image forming apparatus used in the present invention include a monochrome printer, a copying machine, a color printer, a color copying machine and a facsimile.

The image forming apparatus has a charging unit for uniformly charging the photoconductor, and then an exposure for imagewise exposing the photoconductor to dissipate the charge in the exposed portion to form an electrostatic latent image. A unit, a developing unit that visualizes and develops the electrostatic latent image by attaching charged toner, a transfer unit that transfers the obtained visible image to a transfer material such as transfer paper, by heating, pressing, etc. A fixing unit that fixes the visible image on the transfer material and a cleaning unit that removes the toner remaining on the surface of the photoconductor after the toner is transferred to the transfer material are provided. Further, in some cases, a charge eliminating unit for removing charges remaining on the surface of the photoreceptor after cleaning is provided. Further, a carrying unit for carrying the recording medium (paper) is provided.

In the electrophotographic apparatus of the present invention, as the charging device, a non-contact charging device such as a corona charging device typified by a corotron or a scorotron; a contact charging device such as a charging roller or a charging brush is used. Light exposure is halogen lamp, fluorescent lamp, laser (semiconductor, He-Ne), LED
Using a light source such as
The exposure is performed from the inside of the photoconductor. Further, the development is carried out by a dry development method such as cascade development, contact or non-contact development with non-magnetic one-component toner, contact or non-contact development with magnetic one-component toner, two-component magnetic brush development or wet development method with liquid toner. Done. Transfer is performed by an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, an adhesive transfer method, or the like, and fixing is performed by heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like. The cleaning is performed by brush cleaning, magnetic brush cleaning, electrostatic brush cleaning, magnetic roller cleaning, blade cleaning, or the like.

In particular, the photoconductor of the present invention can provide a high quality image and is therefore suitable for a high resolution image forming apparatus. In particular, it can be used for an image forming apparatus that obtains an image having a resolution of 600 dpi or more. Further, in the image forming apparatus using the photoconductor of the present invention, when the light source is a laser beam, not only a light source such as a laser beam having a conventionally known wavelength range but also a light source having a wavelength range of 380 nm to 600 nm is used. It is considered that the effect of the present invention can be achieved also in the image forming apparatus.

FIG. 1 shows an example of the dip coating device used in the present invention. The base body 1 is fixed to the arm 3 by a gripping mechanism 2. The arm 3 is moved up and down by a belt 4 via, for example, a ball screw, and the base 1 is immersed in a coating tank 5 filled with a photosensitive layer forming coating material. Then, by pulling up the substrate 1, a photosensitive layer is formed on the coated surface on the outer surface of the substrate 1. The paint is supplied to the coating tank 5 by the pump 6 through the filter 7. The overflowing paint is collected by the paint receiver 8 and stored in the tank 9. The filter 7 is for removing dust and the like, and 10 is a stirring device for keeping the paint uniform. 11 is a shield for adjusting the solvent vapor concentration.

[0034]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, "part" used in the examples means "part by weight" unless otherwise specified.

(Preparation of Coating Solution for Charge Generation Layer) 10 parts of azo compound having the following structure was added to 150 parts of 4-methoxy-4:
-In addition to methylpentanone-2, pulverization and dispersion treatment was performed with a sand grind mill.

[0036]

[Chemical 1]

The pigment dispersion obtained here was used as polyvinyl butyral (manufactured by Denki Kagaku Kogyo KK, trade name # 6000-).
C) 5% dimethoxyethane solution (100 parts) and a phenoxy resin (manufactured by Union Carbide, trade name PKHH) 5% dimethoxyethane solution (100 parts) are added to a mixed solution, and finally a solid content concentration of 4.0% is obtained. A coating liquid for the generating layer was prepared.

(Preparation of coating liquid for charge transport layer) 100 parts by weight of the following hydrazone compound

[Chemical 2]

1 part by weight of the following cyano compound,

[Chemical 3]

8 parts of 3,5-di-t-butyl-4-hydroxytoluene (hereinafter abbreviated as BHT) and JP-A-3-22
100 parts of the following polycarbonate resin having two repeating structural units (monomer molar ratio 1: 1) produced by the production method described in the example of 1962 gazette.

[0041]

[Chemical 4]

Was dissolved in a mixed solvent of toluene and tetrahydrofuran to finally obtain a charge transport layer coating liquid having a solid content concentration of 21%.

(Example) As a substrate for an electrophotographic photoreceptor,
Length 2 with a mirror finish on the surface made of aluminum alloy
After performing general pretreatment (degreasing, neutralizing, washing with water) using a cylindrical substrate having a diameter of 45 mm, a diameter of 30 mm and a thickness of 1 mm,
Sulfuric acid concentration 180g / l, dissolved aluminum concentration 4.5 ±
Anodizing treatment was performed for 18 minutes under the conditions of 0.5 g / l, anodizing treatment solution concentration of 14 ° C., and current density of 1.3 A / dm ² to obtain an anodized film of 6.0 μm. Then nickel acetate sealant (Okuno Pharmaceutical Co., DX-500, concentration 13g
/ L) is used to perform a nickel acetate sealing treatment for 10 minutes at a liquid temperature of 95 ° C and a pH of 5.5, and then hot water sealing at a liquid temperature of 95 ° C for 20 minutes with hot water having a pH of 7 Pore treatment was performed. After washing with water, the substrate was dipped in a water tank and dried.

The above-mentioned charge generation coating liquid is applied to the substrate by dip coating so that the dry film thickness is 0.5 μm to form a charge generation layer, and then the above charge transport coating liquid is applied to the surface of the charge generation layer. Then, a charge transport layer was formed by performing dip coating so that the dry film thickness was 19 μm.

The film thickness distribution of the substrate was measured 10 minutes after coating the charge transport layer. The following overcoating conditions were set based on the film thickness distribution at the upper end of the substrate. (1) First coating: coating length 30 mm, coating speed 170
mm / min (2) Standby time from the end of the first application to re-immersion: 5 seconds (3) Re-immersion speed: 1000 mm / min (4) Time from the end of re-immersion to the start of second application: 1 second (5) Second coating speed 350 mm / min

On the other hand, the following conditions were set based on the film thickness distribution at the lower end of the substrate. (1) Shield height: 300 mm (2) Shield use started (raised); 10 seconds after coating started (drum lifted) (3) Shield used ended (lower); Coating completed (drum passed liquid level) 10 Second

Thereafter, the coating was applied to 100 substrates while changing the coating conditions as needed to adjust the upper and lower ends.
As a result of coating under the above conditions, a charge transport layer having a uniform film thickness distribution was efficiently obtained. The results are shown in Table 1.

Then, the substrate on which the charge transport layer was formed was heated and dried to obtain a photoconductor. The photoconductor was mounted on a commercially available image forming apparatus (Z820 manufactured by SHP) and an image was formed, and a good image was obtained. The results are shown in Table 1 and FIG.

(Comparative Example) The same procedure as in Example 1 was performed until the charge transport layer was coated. The charge transport layer coating liquid was applied to 100 substrates without setting the coating conditions obtained from the above film thickness distribution measurement. At this time, the coating conditions were constant. When the film thickness distribution was measured after heating and drying, the film thickness at the sagging portion at the upper end became thin after the 30th application, and the film thickness deviation in the image region was too large to obtain an appropriate film thickness distribution. The results are shown in Table 1 and FIG.

Then, the substrate on which the charge transport layer was formed was heated and dried to obtain a photoreceptor. When the image bearing member was mounted on a commercially available image forming apparatus (Z820 manufactured by SHP) and an image was formed, an image defect occurred and a good image could not be obtained.

[0051]

[Table 1]

[0052]

According to the present invention, a photoconductor having a coating film having a uniform film thickness distribution can be efficiently obtained, and the occurrence of defective photoconductors can be minimized. Further, according to the present invention, a photosensitive member having a photosensitive layer having a uniform film thickness distribution can be obtained. Therefore, when an image is formed using the photosensitive member, a good image can be obtained.

[Brief description of drawings]

[Figure 1] Immersion coating device

[Fig. 2] Film thickness distribution

Continued front page    (72) Inventor Fumitaka Minegishi             1060 Narita, Odawara City, Kanagawa Prefecture Mitsubishi Chemical             Within the corporation F-term (reference) 2H068 EA16 EA19 EA41

Claims (5)

[Claims] 1. A method for producing an electrophotographic photosensitive member, comprising forming a coating film on a substrate for an electrophotographic photosensitive member by a dip coating method,
A film thickness distribution of the coating film is measured after coating and before heating and drying, and coating conditions are set based on the measurement results to control the film thickness distribution of the coating film. Production method. 2. The method for manufacturing an electrophotographic photosensitive member according to claim 1, wherein the film thickness distribution of the coating film is controlled by performing multi-step coating or plural times coating as the coating conditions. 3. The film thickness distribution of a coating film is controlled by adjusting a waiting time of a photoreceptor in a shield for adjusting a vapor concentration of a coating solvent in a coating process as the coating condition. Item 3. The electrophotographic photoreceptor according to any one of Items 1 and 2. 4. An electrophotographic photosensitive member manufactured by the manufacturing method according to claim 1. 5. An image forming apparatus using the electrophotographic photosensitive member according to claim 4.