JP2003156863A - Electrophotographic photoreceptor dip-coating method and electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor dip-coating method capable of obtaining a good uniform film layer by preventing the occurrence of air bubbles in coating liquid and suppressing the irregularity of the liquid level when an object to be coated is separated from the liquid level, and to provide the electrophotographic photoreceptor. SOLUTION: In the electrophotographic photoreceptor dip-coating method for dipping the object to be coated in the coating liquid, and forming the film layer on the object to be coated, the object to be coated is dipped into the coating liquid while making the opening part of the object to be coated facing downwards and keeping the air inside the object to be coated, and when the uppermost end of the object to be coated is dipped, dipping the object is stopped once, and also, the inside air is partly discharged, thereafter, the object to be coated is pulled up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dip coating method for immersing an article to be coated in a coating solution to form a coating layer, and particularly to an electrophotographic photoreceptor (hereinafter also simply referred to as a photoreceptor).
And the electrophotographic photosensitive member produced by the method.

[0002]

2. Description of the Related Art A dip coating method is suitable as a method for forming a uniform coating layer on the outer peripheral surface of an object to be coated, and is widely used in the production of photoreceptors. In such a dip coating method, in order to grip an object to be coated, a rubber member (balloon chuck) capable of expanding and contracting a gripping member is inserted inside the object to be contracted, and then air is pressed into the rubber member. Then, it is usually performed that the product is inflated and brought into pressure contact with and closely adhered to the inner wall of the object to be coated, the object to be coated is gripped, dipped in the coating solution and applied.

However, when the article to be coated is dipped in the coating solution, the coating solution may enter the article from the lower end opening of the article to be adhered to the inner peripheral surface of the article to be coated. Had to prevent. For this reason, it has been practiced to fit the gripping device to the object to be coated in a hermetically sealed manner, and to keep the inner lower portion of the object to be coated in an airtight state except the lower end opening.

On the other hand, as the solvent for the coating liquid, a solvent having a relatively low boiling point and high volatility is usually used. When the article to be coated is immersed in a coating solution prepared using such a highly volatile solvent, the solvent on the liquid surface at the lower end opening vaporizes, and the vaporized solvent vapor increases the gas volume inside the article to be coated. To do. When the gas volume inside the object to be coated increases during dip coating, the gas (air containing solvent) that has become larger than the lower end of the object to be coated jumps out into the coating liquid as bubbles. When the popped bubbles rise to the surface of the coating liquid along the outer peripheral surface of the object to be coated, the surface of the coating liquid is disturbed, uneven coating may occur in the formed coating layer, and the uniformity may be impaired.

In order to prevent the generation of such bubbles, a method (venting method) using a gripping mechanism having a function of adjusting the air pressure in the object to be coated is disclosed in JP-A-60-132678 and JP-A-60-255164. JP-A-63-3151
No. 67 publication.

However, although such a method could solve the generation of bubbles to some extent, it could not prevent the generation of fine unevenness in the coating layer, and it was still insufficient as a countermeasure.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above problems, and the liquid surface is less disturbed when an object to be coated separates from the liquid surface without generating bubbles in the coating liquid, and therefore, An object of the present invention is to provide a method for dipping and coating an electrophotographic photoreceptor, which can obtain a good coating layer without unevenness, and an electrophotographic photoreceptor.

[0008]

As a result of intensive studies on the above problems, the present inventors have found that the timing of adjusting the pressure inside the object to be coated has a great influence on the turbulence of the liquid surface, We have found that it causes unevenness in the skin. It has been found that performing this improvement leads to an improvement in coating property, and thus in a coating yield, and has reached the present invention.

[1] In the dip coating method for an electrophotographic photoreceptor, which comprises immersing an article to be coated in a coating liquid to form a coating layer on the article to be coated, the opening of the article to be coated is set downward, The object to be coated is immersed in the coating liquid in a state where air is contained inside the object to be coated, and when it is immersed to the uppermost end to be coated, it is temporarily stopped and part of the air inside is removed. After that, the method for dipping coating an electrophotographic photosensitive member is characterized in that the article to be coated is pulled up.

[2] The dip coating method for an electrophotographic photosensitive member according to [1], wherein the pulling speed is lower than the dipping speed.

[3] An electrophotographic photosensitive member produced by the dip coating method for an electrophotographic photosensitive member according to [1] or [2].

In the above-mentioned constitution of the present invention, the article to be coated is a substrate of the electrophotographic photosensitive member primarily, and its concrete shape and material will be described later. Similarly, the coating liquid is a coating liquid for the photosensitive layer or the photoreceptor auxiliary layer.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view of the steps in the dip coating method for the photoconductor of the present invention. The dip coating method for the photoconductor (hereinafter, also simply referred to as dip coating method) is as follows: A → B → C in FIG.
→ D → E process is performed.

FIG. 1A shows a state in which the object to be coated 2 is gripped by the gripping device 1 and is relatively close to the surface of the coating liquid 4 while being gripped by the gripping device 1.

In the figure, 3 is a solvent vapor atmosphere, 5 is an air vent pipe, and 6 is a valve. B of FIG. 1 shows a state immediately after the object to be coated 2 starts to be dipped in the coating liquid 4.

In FIG. 1C, the article to be coated 2 is immersed in the coating solution 4 up to the upper end leaving the uncoated portion 7 and then temporarily stopped, and at the same time, the valve 6 of the air vent pipe 5 is opened to open the article 2 to be coated. Part of the air inside the chamber is replaced with coating liquid 4
It shows a state of being penetrated from the lower end to a penetration depth of 8.

FIG. 1D shows a state in which the coating layer 9 is being formed on the outer peripheral surface of the coating object 2 while the coating object 2 is being pulled up from the coating liquid 4.

FIG. 1E shows a state in which the article 2 to be coated is pulled up from the coating liquid 4 and the coating layer 9 is formed on the outer peripheral surface of the article 4 to be coated.

The gripping device grips the shaft of the object to be coated perpendicularly or almost perpendicularly to the liquid surface of the coating liquid 4, and while the liquid is immersed in the coating liquid, the coating liquid is kept inside the object to be coated. It is a chuck that functions to prevent entry.

The chuck is not particularly limited as long as it can vertically hold an object to be coated and can prevent the coating liquid from entering the inside of the object to be coated. Specifically,
A balloon chuck, an O-ring chuck, a mechanical chuck, etc. can be mentioned. Of these, a balloon chuck that is easy to use in combination with an air vent pipe and a gripping device is preferable.

The length of the uncoated portion on the top of the article to be coated varies depending on the electrophotographic apparatus in which the photoconductor prepared is loaded, but is preferably 0.0 to 2.0 cm. Therefore, the uppermost coating end is 0.0 to 2.0 cm below the upper end of the object to be coated.

The pause time is preferably longer than 0 seconds and 60 seconds or less, more preferably 30 seconds or less, and further preferably 2 to 10 seconds. If the pause time is 0 seconds, the time for opening the inside of the object to be coated may not be in time for the application, and air bubbles may fly out from the lower end of the object to be coated into the coating liquid.
If it is longer than 60 seconds, the time required for coating becomes longer and the lower coating layer elutes into the coating liquid, which may contaminate the coating liquid.

The pulling rate varies depending on the viscosity of the intermediate layer, the charge generating layer, the charge transporting layer, etc., the solid content concentration, the temperature, the required thickness of the coating layer, etc., but is 0.1 to 5.0 cm /
s is preferable, and 0.2 to 3.0 cm / s is more preferable. The immersion speed is preferably 1.1 to 20 times faster than the pulling speed, and more preferably 1.2 to 10 times faster. If it is less than 1.1 times, it will be disadvantageous because it takes time in the process, and if it exceeds 20 times, the liquid surface will be disturbed at the time of dipping and unevenness of the coating layer will be likely to occur.

The amount of air to be evacuated depends on the temperature and viscosity of the coating liquid, the temperature of the object to be coated, the size and heat capacity of the object to be coated, and is 0.5 to 5.0 c based on the lower end of the object to be coated.
The amount is preferably such that the coating liquid penetrates into the object to be coated up to m. If the depth of penetration of the coating liquid is less than 0.5 cm, it is not possible to deal with shaking and vibration of the liquid, and bubbles easily pop out into the coating liquid. Shaking is large and uneven coating is likely to occur.

The timing of bleeding the internal air preferably starts at the same time as the temporary stop and is completed within the temporary stop time.

Specifically, this can be done by controlling the timing and time for opening and closing the valve 6 of the air vent pipe 5 penetrating the gripping device 1 shown in FIG. The same applies to opening the inside of the object to be coated.

Next, members according to the present invention will be described. As the coating solvent according to the present invention, a commonly used solvent is used.

Specifically, chlorobenzene (specific gravity 1.1)
06), 1,4-dioxane (specific gravity 1.039), toluene (specific gravity 0.866), methyl ethyl ketone (specific gravity 0.805), tetrahydrofuran (specific gravity 0.88).
9), cyclohexanone (specific gravity 0.945), 1,3-
Dioxolane (specific gravity 1.065), ethylene glycol dimethyl ether (specific gravity 0.867), t-butyl acetate (specific gravity 0.867), 2-methoxy-2-methyl-4-
Pentanone (specific gravity 0.910), n-butanol (specific gravity 0.810), isopropyl alcohol (specific gravity 0.78)
5), ethanol (specific gravity 0.791), methanol (specific gravity 0.792) and the like, but not limited thereto.

Here, the coating solvent means a coating composition obtained by removing solids and additives.

As the member of the article to be coated according to the present invention,
It is a so-called photoconductor substrate, and examples thereof include, but are not limited to, the following.

1) A conductive metal member such as aluminum or stainless steel 2) A member provided with a conductive thin metal layer such as aluminum, palladium and gold on paper or plastic 3) On paper or plastic , Conductive polymer,
A member coated or vapor-deposited with a layer of a conductive compound such as indium oxide and tin oxide.

Of these, conductive metals such as aluminum are preferably used. As the shape of the coated object,
A cylindrical substrate capable of forming an image endlessly by rotating is preferable. The thickness, diameter and length of the cylindrical substrate are not particularly limited and can be arbitrarily determined depending on the electrophotographic image forming apparatus used. The straightness of the cylindrical substrate is preferably 0.10 mm or less and the deflection is preferably 0.10 mm or less. If the circularity and the shake range are exceeded, good image formation becomes difficult.

The coating liquid is specifically a photosensitive layer liquid constituting the photosensitive member or a photosensitive member auxiliary layer liquid such as an intermediate layer or a protective layer.

The photoconductor according to the present invention will be described below. The photoreceptor is, for example, one in which a charge generation layer and a charge transport layer are sequentially laminated on an object to be coated, or an intermediate layer, a charge generation layer, and a charge transport layer are sequentially laminated on the object to be coated. Examples thereof include, but are not limited to, those obtained by further laminating a surface layer on the charge transport layer.

The layer structure of the photoconductor will be specifically described. << Intermediate Layer >> The intermediate layer is provided between the article to be coated and the photosensitive layer in order to improve the adhesion between the article to be coated and the photosensitive layer to be described later or to prevent charge injection from the article.

Examples of the material for the intermediate layer include, but are not limited to, polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of the repeating units of these resins. It is not something that will be done. Among these resins for the intermediate layer, a polyamide resin can be mentioned as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.1 to 5.0 μm.

In addition to the above, an intermediate layer preferably used is, for example, an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent and a titanium oxide coupling agent. The thickness of the intermediate layer using the curable metal resin is preferably 0.05 to 2 μm.

The intermediate layer is prepared by coating a coating solution for the intermediate layer prepared by dissolving the above resin with a coating solvent on the article to be coated by the dip coating method of the present invention and drying it. Preferably.

As the coating solvent, for example, methanol,
It is preferable to use ethanol, methyl ethyl ketone, toluene and the like.

The coating method of the present invention is described in JP-A-6-25445.
It is advantageously applied to multiple coating and overflow methods such as Japanese Patent No. 9 and Japanese Utility Model Laid-Open No. 6-7868.

<< Photosensitive Layer >> The photosensitive layer may have a single-layer photosensitive layer structure in which one layer has a charge generating function and a charge transporting function on the intermediate layer, but the photosensitive layer function is more preferable. It is preferable to separate the charge generation layer and the charge transport layer from each other. By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, it is preferable to have a charge generation layer on the intermediate layer and a charge transport layer on the intermediate layer. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging.

If necessary, a surface layer can be provided on the charge transport layer. The surface layer has hardness and improves the abrasion resistance of the photoconductor, and is used by being provided on the uppermost layer of the photoconductive layer.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor and the method for producing it will be described below. <Charge Generation Layer> The charge generation layer contains a charge generation substance. If necessary, binder resin,
Other additives may be included.

As the charge generating substance, known charge generating substances can be used. Specific examples thereof include phthalocyanine pigments, azo pigments, perylene pigments, and azurenium pigments, but are not limited thereto. Among these, the one that can minimize the increase in residual potential with repeated use is a stable aggregate structure between multiple molecules,
It has a potential structure, and specific examples thereof include charge generating substances such as phthalocyanine pigments and perylene pigments having a specific crystal structure. For example, CGM such as titanyl phthalocyanine having a maximum peak at 27.2 ° of Bragg angle 2θ with respect to Cu-Kα line and benzimidazole perylene having a maximum peak at 22.4 of 2θ hardly deteriorates due to repeated use and remains. The potential increase can be reduced.

When a binder is used as a dispersion medium for the charge generating substance in the charge generating layer, a known resin can be used as the binder, for example, formal resin,
Examples thereof include butyral resin, silicone resin, silicone-modified butyral resin, and phenoxy resin, but are not limited thereto. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.1 to 2.0 μm.

For the charge generation layer, a charge generation layer coating solution prepared by dispersing a charge generation substance together with a binder resin and other additives in a coating solvent is applied onto the intermediate layer by the dip coating method of the present invention. It is preferable to apply a uniform film thickness and dry it to prepare.

As the coating solvent, for example, methanol,
Ethanol, methyl ethyl ketone, toluene, acetic acid t-
Butyl and 2-methoxy-2-methyl-4-pentanone are preferably used.

As a means for dispersing the charge generating substance in the coating liquid, for example, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer and the like can be used, but the means is not limited to these.

<Charge Transport Layer> The charge transport layer contains a charge transport material. If necessary, a binder resin and other additives may be contained as other substances.

As the charge transport material, known materials can be used. Specifically, a triphenylamine derivative,
Examples thereof include hydrazone compounds, styryl compounds, benzidine compounds and butadiene compounds, but are not limited to these.

Known resins can be used as the binder, and specific examples thereof include polystyrene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin. , Alkyd resin, polycarbonate resin, silicone resin,
Examples thereof include, but are not limited to, a melamine resin and a copolymer resin containing two or more of repeating units of these resins. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinylcarbazole can be used. Preferred as a binder for these charge transport layers is a polycarbonate resin. Polycarbonate resin is preferable in terms of improving the dispersibility of the charge transport material and the electrophotographic characteristics.

The ratio of the binder resin to the charge transport material is 1 charge transport material to 100 parts by weight of the binder resin.
0 to 200 parts by mass is preferable. The thickness of the charge transport layer is 1
0 to 30 μm is preferable.

For the charge transport layer, a charge transport layer coating solution prepared by dissolving a charge transport material, a binder resin, and other substances in a coating solvent is fixed on the charge generating layer by the dip coating method of the present invention. It is preferable to apply the film having the thickness of 1 and dry.

As the coating solvent, for example, methanol,
Ethanol, methyl ethyl ketone, toluene, cyclohexanone and tetrahydrofuran, chlorobenzene,
It is preferable to use dioxolane, dioxane or the like.

As a means for dissolving the charge transport substance in the coating liquid, for example, an ultrasonic disperser, a ball mill, a homomixer and the like can be used, but the means is not limited to these.

All coating layers of photoreceptor (intermediate layer + charge generation layer +
It is preferable that the thickness of the charge transport layer) is approximately 10 to 37 μm.

Next, an image forming apparatus using the photoconductor manufactured by the dip coating method of the present invention will be described.

FIG. 2 is a cross-sectional view showing an example of an electrophotographic image forming apparatus for forming an image by using a photoreceptor prepared by the dip coating method.

The electrophotographic image forming apparatus is an apparatus for forming an image by using a photosensitive drum and repeating charging, exposing, developing, transferring, separating and cleaning steps.

The electrophotographic image forming apparatus shown in FIG. 2 will be described below. Light is emitted from the semiconductor laser light source 21 based on information read by a document reading device (not shown). This is scanned by the polygon mirror 22 and is irradiated onto the surface of the photoconductor drum through the fθ lens 23 that corrects the distortion of the image, and an electrostatic latent image is formed by the digital exposure method. The photoconductor drum 24 is the charger 2 in advance.
It is uniformly charged by 5, and starts rotating clockwise in accordance with the timing of light irradiation.

The electrostatic latent image on the surface of the photosensitive drum is developed by the developing device 2.
Inverse development is performed by 6 to form a toner image. The formed toner image is transferred by the action of the transfer device 27 to the transfer body 28 that has been conveyed at the same timing. Further, the photosensitive drum 24 and the transfer body 28 are separated by a separator (separation pole) 2
Although separated by 9, the toner image is transferred and carried by the transfer member 28, guided to the fixing device 30, and fixed to form a print image.

Thereafter, the photoconductor drum 24 is cleaned by the cleaning device 31 of the cleaning blade type to remove the untransferred toner and the like remaining on the surface of the photoconductor drum, and the precharge exposure (PCL) 32 removes the residual charge. , The next image is uniformly charged by the charger 25 again.

The transfer member 28 is typically plain paper, but is not particularly limited as long as it can transfer the unfixed image after development, and includes a PET base for OHP and the like.

The cleaning blade 33 has a thickness of 1
A rubber-like elastic body of about 30 mm is used, and urethane rubber is often used as the material.

[0066]

The present invention will be described in more detail with reference to the following examples, but it goes without saying that the embodiments of the present invention are not limited to the following examples. In the text, "part" means "part by mass"
Represents

Example 1 (Coating of Intermediate Layer (UCL)) The following intermediate layer coating solution was prepared, and the lower end portion was opened at an outer diameter of 4 cm and a length of 40 cm at room temperature and a liquid temperature of 25 ° C.
An aluminum cylindrical substrate having a lower volume inside the substrate of about 1000 cm ³ was immersed in the coating liquid at a speed of 2 cm / sec,
When the uncoated portion at the upper end of the substrate was 1 cm, it was stopped for 10 seconds, and as the air inside the substrate, about 1 cm inside the drum, the amount of air into which the coating liquid penetrated was evacuated. After that 1.
When the cylindrical substrate was pulled up at a speed of 2 cm / sec, no bubbles were generated and there was no coating failure such as coating unevenness.
A good coating film having a dry film thickness of about 2 μm was obtained.

<Intermediate Layer Coating Liquid> The following intermediate layer dispersion liquid was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; Rigimesh filter manufactured by Nippon Pall Co., nominal filtration accuracy: 5 μm, pressure; 5 Pa / cm ² ) to prepare an intermediate layer coating solution.

Intermediate layer dispersion liquid Polyamide resin CM8000 (manufactured by Toray) 1.0 part Titanium oxide SMT500SAS (manufactured by Teika; surface treatment is silica treatment, aluminum treatment, and methylhydrogenpolysiloxane treatment) 3.0 parts Methanol 10.0 parts Dispersion was carried out batchwise with a sand mill as a disperser for a dispersion time of 10 hours to prepare an intermediate layer dispersion liquid.

Example 2 (Coating of charge generation layer (CGL)) The following charge generation layer liquid coating solution was prepared, and the lower end was opened at an outer diameter of 4 cm and a length of 40 cm at room temperature and a liquid temperature of 25 ° C. The cylindrical base made of aluminum having a volume of about 1000 cm ³ in the lower part of the base was immersed in the coating liquid at a speed of 2 cm / sec, and when the uncoated portion at the upper end of the base was 0.7 cm, it was stopped for 8 seconds, and The air inside the substrate is 1 cm in the drum.
About the amount of air into which the coating liquid penetrates was removed. Then, when the cylindrical substrate was pulled up at a speed of 1.3 cm / sec, no bubbles were generated, no coating failure such as coating unevenness was observed, and a good coating film with a dry film thickness of about 2 μm was obtained.

[0071]   <Charge generation layer coating liquid>   Y-type oxytitanyl phthalocyanine (Cu-Kα characteristic X-ray diffraction   Large peak angle is 2θ and 27.3 degrees) 20g   Polyvinyl butyral (# 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 g   T-Butyl acetate 700 g   4-methoxy-4-methyl-2-pentanone 300 g It was dispersed using a sand mill for 10 hours.

Example 3 (Coating of charge transport layer (CTL)) The following charge transport layer coating solution was prepared and the lower end was opened at an outer diameter of 4 cm and a length of 40 cm at room temperature and a liquid temperature of 25 ° C. Further, an aluminum cylindrical substrate having a lower volume inside the substrate of about 1000 cm ³ was immersed in a coating solution at a speed of 1 cm / sec, and when the uncoated portion at the upper end of the substrate was 0.5 cm, the substrate was stopped for 5 seconds and As the internal air, the amount of air that the coating liquid penetrated into the drum was removed by about 0.5 cm. Then, when the cylindrical substrate was pulled up at a speed of 0.2 cm / sec, no bubbles were generated, no coating failure such as coating unevenness was found, and a good coating film with a dry film thickness of about 25 μm was obtained.

<Charge Transport Layer Coating Liquid> Charge transport material (D1) 75 g Polycarbonate resin “UPILON-Z300” (manufactured by Mitsubishi Gas Chemical Co., Inc.) 100 g Methylene chloride 750 g Using the above coating liquid, an aluminum cylindrical substrate under the above conditions An intermediate layer, a charge generation layer, and a charge transport layer in that order,
An electrophotographic photosensitive member was produced, and a photographed image was observed. The image was good with no image defects such as coating unevenness.

Comparative Example 1 Coating was carried out in the same manner as in Example 1 except that there was no down time at the upper end and no deaeration was performed.

When pulled up, air bubbles were generated from the opening at the lower end of the cylindrical substrate and the liquid surface of the coating liquid was disturbed, so that the coating film formed on the outer peripheral surface of the cylindrical substrate was markedly uneven, and the electrophotographic photoreceptor It could not withstand the use as.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the inner air was not evacuated only after reaching the lower end in Example 3 and stopping for 3 seconds. Since air bubbles were generated from the part and the liquid surface of the coating liquid was disturbed, the coating film formed on the outer peripheral surface of the cylindrical substrate was markedly uneven, and it could not be used as an electrophotographic photoreceptor.

[0077]

EFFECT OF THE INVENTION According to the present invention, an electrophotographic photosensitive member which does not generate air bubbles in the coating liquid and has little disturbance of the liquid surface when an object to be coated is separated from the liquid surface, and thus a good coating layer having no unevenness can be obtained. And an electrophotographic photosensitive member.

[Brief description of drawings]

FIG. 1 is a schematic view of steps in a dip coating method for a photoreceptor of the present invention.

FIG. 2 is a cross-sectional view showing an example of an electrophotographic image forming apparatus that forms an image using a photoreceptor prepared by a dip coating method.

[Explanation of symbols]

1 gripping device 2 Object to be coated 3 solvent vapor atmosphere 4 coating liquid 5 Air vent pipe 6 valves 7 Unapplied part 8 penetration depth 9 Coating layer

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Claims (3)

[Claims] 1. A dip coating method for an electrophotographic photosensitive member comprising immersing an article to be coated in a coating solution to form a coating layer on the article to be coated, wherein an opening of the article to be coated is placed downward and The object to be coated is immersed in the coating liquid in a state where air is contained inside the coated object, and when the material is immersed to the uppermost end to be coated, the suspension is temporarily stopped and a part of the internal air is removed, After that, the electrophotographic photosensitive member is dipped and coated, wherein the coating object is pulled up. 2. The dip coating method for an electrophotographic photosensitive member according to claim 1, wherein the pulling speed is lower than the dipping speed. 3. An electrophotographic photosensitive member produced by the dip coating method of the electrophotographic photosensitive member according to claim 1.