JPH0889879A - Manufacture of coated cylinder - Google Patents

Abstract

PURPOSE: To provide a method for making a coated cylinder which is free from defects due to scattering, etc., of coating liquid from a coating liquid surface in a improved immersion coating method in which the cylinder is pulled up from coating liquid. CONSTITUTION: In the manufacture of a coated cylinder, a hollow cylinder with one end open and the other closed is attached to a support member, and it is immersed into coating liquid from the open end, and pulled up, when the cylinder is pulled up from the coating liquid, most part of the cylinder is pulled up at a high speed, and the rest is pulled up at a low speed.

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 a cylinder having a coating film. Specifically, for example, a PPC copier,
The present invention relates to a method for manufacturing a cylinder (roll) used as a support for an electrophotographic photosensitive member such as an OPC photosensitive drum used in a laser beam printer, which has a coating film without coating unevenness or defects. is there.

[0002]

2. Description of the Related Art Conventionally, various methods have been known as a method for forming a coating film on the surface of a cylinder. However, when importance is attached to the smoothness of the coating film, the dip coating method is adopted. Has been done. In a general dipping method, a cylindrical body is dipped in a coating liquid and then pulled up at an appropriate speed to form a coating film on the outer surface of the cylindrical body. In this method, a substantially uniform coating film can be formed on the outer surface of the cylindrical body by appropriately setting the viscosity of the coating liquid, the pulling rate, and the like. However, in the case of a cylinder whose both ends in the length direction are open, when the cylinder is immersed in the coating liquid, the coating liquid also enters the inside of the cylinder, so that a coating film is formed on the inner surface. However, there is a problem that not only the coating liquid is wasted, but also the inner surface of the cylindrical body is difficult to dry and contamination occurs.

In order to solve this problem, a lid is attached to the end (lower part) of the cylindrical body which is immersed in the coating solution, and when the cylindrical body is immersed in the coating solution, the coating solution penetrates into the inner surface of the cylindrical body. Prevent
A method of preventing the coating liquid from adhering to the inner surface of the cylindrical body has also been proposed. However, in this method, it is troublesome to attach the lid, so that the workability is poor, and when the cylinder is immersed in the coating liquid, the coating liquid also adheres to the surface of the lid, so that the lid must be washed. However, there is a problem that maintenance work is complicated.

On the other hand, the end (upper part) of the cylindrical body which is not immersed in the coating liquid is closed, air is confined inside the cylindrical body when the cylindrical body is immersed in the coating liquid, and the coating liquid is applied by the air pressure inside the cylindrical body. There is also proposed a method of preventing the infiltration of water into the inside of the cylinder.
However, when the cylinder whose upper part is closed in this way is immersed in the coating liquid and pulled up, the volume of gas such as air trapped inside the cylinder expands as the solvent constituting the coating liquid evaporates. Then, it may become larger than the cylinder volume. In such a case, the gas that has expanded and cannot be accommodated inside the cylinder becomes bubbles from the lower end of the cylinder and floats on the surface of the coating liquid. The floating bubbles bounce on the surface of the coating liquid and disturb the surface of the coating liquid, which causes a problem in that the coating film formed on the outer surface of the cylinder is defective.

Various methods have been proposed for the purpose of suppressing the floating of such bubbles. For example, as described in JP-B-62-4187 and JP-A-63-77567, a coating method characterized by removing gas such as air trapped in a cylinder, and a coating method Kaihei 1-123664, Japanese Patent Publication No. 4-689
There is a method such as described in Japanese Patent Publication No. 89 etc. in which the floating of bubbles is suppressed by adjusting the pressure inside the cylinder and the external pressure. In these proposed methods, in order to prevent the bubbles from floating, the pressure is adjusted so that the coating liquid slightly penetrates into the lower end of the cylinder, but when the cylinder is pulled up from the coating liquid, There is a problem that the coating liquid slightly invading the lower end falls onto the coating liquid surface to cause liquid splashing, and the coating liquid flowing down from the surface of the cylindrical body causes a coating film defect on the outer surface of the cylindrical body.

[0006]

The present invention has been completed as a result of extensive studies aimed at solving the problems existing in the above-mentioned prior art, and is a dip coating method in which a cylinder is pulled up from a coating liquid. It is an object of the present invention to provide a method for manufacturing a cylindrical body having a coating film free from defects such as splashing of liquid from the surface of the coating liquid.

[0007]

In order to solve the above-mentioned problems, in the invention described in claim 1 of the present invention, one end of the cylindrical body whose both ends in the length direction are opened is closed and the other end is opened. Attached to the support member as it is, immersed in the coating liquid from the open end side, and when pulling up, to manufacture a barrel having a coating film on the outer side of the barrel, when pulling up the barrel from the coating liquid, Most of them are pulled at high speed, and the rest are pulled at low speed.

Further, in the invention according to claim 4 of the present invention, one end of the tubular support member for an electrophotographic photosensitive member whose both ends in the lengthwise direction are opened is closed, and the other end is left open, and the supporting member is left open. In order to manufacture a support for an electrophotographic photosensitive member having a photosensitive coating film on the outer side of the support by immersing it in the photosensitive coating solution from the opened end side and pulling it up.
When the support is pulled up from the photosensitive coating solution, a portion of the image forming portion is pulled up at a high speed, and a portion of the non-image forming portion is pulled up at a low speed.

The present invention will be described in detail below. The method of the present invention is applied to a cylindrical body whose both longitudinal ends are open. For example, in the case of a support for an electrophotographic photosensitive member, any of those used for known electrophotographic photosensitive members can be used.
Specifically, for example, a metal drum such as aluminum, stainless steel, or copper, or a laminate of these metal foils,
Examples include vapor deposition materials. Furthermore, a metal drum, carbon black, copper iodide, a polymer drum, a conductive material coated with a suitable binder together with a suitable binder to conduct a conductive treatment, such as a plastic drum and a paper tube. In addition, a conductive plastic drum containing a conductive material such as metal powder, carbon black, and carbon fiber can be used. Also,
A charge generation layer, an undercoat layer or the like may be provided on these supports. The size of the cylinder can be selected in the range of 30 mm to 140 mm in outer diameter and in the range of 260 mm to 1000 mm in length according to the use of the cylinder.

According to the method of the present invention, one end (upper part) of the cylindrical body is closed and the other end is left open, and the axis of the cylindrical body is perpendicular or nearly perpendicular to the liquid surface of the coating liquid. Dip it in the coating solution from the open end side. Closing the top of the cylinder is to prevent the air trapped inside the cylinder from leaking when the cylinder is immersed in the coating liquid. Is unlimited. For example, a frusto-conical lid that fits inside the upper opening of the tubular body and seals it, a lid that has a structure in which it is fitted inside the tubular body in a reduced state and then expanded to contact the inner wall for sealing. Is mentioned.

The coating liquid in the present invention is, for example,
In the case of a photosensitive coating liquid for an electrophotographic photoreceptor, one or more kinds selected from charge transport materials, charge generating materials, dye pigments, electron-withdrawing compounds and the like and a binder are dissolved in a solvent, Alternatively, a dispersed photosensitive coating solution is used. The photosensitive coating liquid may contain known additives such as a lubricant, a leveling agent and an antioxidant.

Known materials can be used as the charge transport material, charge generating material, dye pigment, electron-withdrawing compound, binder and the like. As the binder, for example,
Polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester and butadiene, polyvinyl acetal,
Examples include various polymers such as polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, and epoxy resin.

Examples of the charge transport material include 2, 4, 6
-Trinitrofluorenone, tetracyanokidimethane,
Electron-withdrawing substances such as diphenoquinone derivatives, carbazole, indole, imidazole, oxazole, pyrazole, oxadiazole, pyrazoline, thiadiazole and other complex compounds, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, or these compounds An electron-donating substance such as a polymer having a group consisting of is a main chain or a side chain.

Examples of the charge generating material that generates charge carriers with extremely high efficiency when absorbing light include inorganic photoconductive particles such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide, and amorphous silicon; phthalocyanine. Examples thereof include organic photoconductive particles such as pigments, perinone pigments, thioindigo, quinacridone, perylene pigments, anthraquinone pigments, azo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments, and cyanine pigments. Examples of the dye include triphenylmethane dye, thiazine dye, quinone dye, cyanine dye, pyrylium salt, thiapyrylium salt, and benzopyrylium salt. Examples of the electron withdrawing compound that forms a charge transfer complex with the charge transfer material include electron withdrawing compounds such as quinones, aldehydes, ketones, acid anhydrides, cyano compounds, and phthalides.

Examples of the solvent contained in the photosensitive coating solution according to the present invention include ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N. , N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethylsulfoxide and other aprotic polar solvents; ethyl acetate, methyl formate, methyl cellosolve acetate and other esters; dichloroethane, chloroform and other chlorinated hydrocarbons; Is mentioned.

There is no particular limitation on the method of immersing the cylindrical body in the coating liquid, and the upper portion of the cylindrical body is closed and the other end is left open to the supporting member, and the shaft of the cylindrical body is positioned relative to the liquid surface of the coating liquid. It may be mounted so as to be vertical or almost vertical, and may be dipped in the coating solution from the open end side while leaving the upper part of the cylinder slightly in the coating solution.
According to the method of the present invention, when pulling up the tubular body from the coating liquid, a method of pulling up most of the tubular body at high speed and pulling up the remaining portion at low speed is adopted. By pulling up the tubular body as above, the coating liquid that has entered the inside of the tubular body when the tubular body separates from the coating liquid is smoothly discharged from the tubular body, and the liquid surface of the coating liquid is not disturbed. It is also possible to prevent the coating liquid from dropping on the surface of the coating liquid and splashing the liquid.
When the cylindrical body is a support for an electrophotographic photosensitive member, the portion corresponding to the image forming portion is pulled up at a high speed, so that a coating film having a uniform thickness is formed.

The speed at which the tubular body is pulled out of the coating liquid can be appropriately selected depending on the diameter of the tubular body, the viscosity of the coating liquid, the thickness of the coating film formed on the outer surface of the tubular body, the productivity and the like. The pulling speed can be selected at a high speed for most of the cylinder, for example, in the range of 50 to 500 mm / min. The rest of the barrel is pulled up slowly. According to experiments conducted by the present inventors, it was found that the object of the present invention can be effectively achieved when the speed at this time is 50 mm / min or less. In particular, if it is 10 mm / min or less, it is preferable that liquid splashing does not occur at all.

Further, according to the experiments conducted by the present inventors, the length of the tubular body portion to be pulled at a low speed when the tubular body is pulled up from the coating liquid is irrespective of the length of the entire tubular body, Therefore, it was found that the object of the present invention can be effectively achieved when the thickness is 30 mm or less. Above all, it is particularly preferable that the length is 10 mm or less from the lower end of the cylindrical body because the production efficiency is improved. When the cylindrical body is a support for an electrophotographic photosensitive member, the remaining portions correspond to the non-image forming portions on both ends of the final product.

The cylinder body can be dipped in and pulled up from the coating liquid by attaching a lid with the upper part of the cylinder body closed to the cylinder body support member and raising and lowering this support member. The supporting member can change the dipping / pulling speed to a desired speed by disposing a driving device on the upper side of the container containing the coating liquid or on the outer side of the container and program-controlling the driving device. In addition, dipping and pulling up
It is preferable that the axis of the cylindrical body is perpendicular to the liquid surface of the coating liquid even during dipping and pulling up.

The cylinder having the coating film obtained by the method of the present invention has no coating unevenness or defects,
It is preferably used as a support for an electrophotographic photosensitive member such as an OPC photosensitive drum used in a laser beam printer.

[0021]

EXAMPLES The contents and effects of the present invention will be described below in more detail with reference to Examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 A charge transport layer coating liquid for an electrophotographic photoreceptor having the following formulation was prepared.

[0022]

[Table 1] Solid content Charge transport material (hydrazone compound) 100 parts Binder (polycarbonate resin) 100 parts Solid content concentration 20% by weight Solvent 1,4-dioxane / tetrahydrofuran 4/6 (weight ratio)

An upper part of a cylindrical cylinder made of aluminum having an outer diameter of 30 mm and a length of 260 mm coated with a charge generation layer is closed by a closing member, and the closing member is connected to a supporting member by a shaft of the cylindrical body. Was installed so that it was vertical. This cylinder was dipped vertically from the released end side in the above-mentioned coating liquid by the elevating device, leaving 2 mm above the cylinder. Then, from the upper end of the cylinder length to 255 mm, the cylinder is pulled up at a speed of 300 mm / min, and the remaining portion (at this point, the height of the coating liquid penetrating into the cylinder is about 10 mm) is raised to 30 mm / min. And pulled up to obtain a cylinder having a coating film on the outer surface of the cylinder. When the appearance of the coating film of the obtained cylindrical body was observed, no coating film defects due to liquid splashing were observed on the outer surface of the cylindrical body.

Comparative Example 1 A cylindrical body having a coating film was obtained by the same method as in Example 1 except that the whole cylindrical body was pulled up at a pulling rate of 300 mm / min in the example described in Example 1. It was When the coating film state of the cylindrical body was examined, the outer surface of the cylindrical body had traces of liquid splashing at seven places, and there were coating film defects, so it could not be used as a product.

[0025]

INDUSTRIAL APPLICABILITY The present invention has the following particularly advantageous effects, and its industrial utility value is extremely large. 1. According to the present invention, since the coating film is not formed on the inner surface of the cylindrical body, the coating liquid is not wasted. 2. According to the present invention, the pulling rate of the tubular body from the coating liquid is appropriately selected, so that the tubular body having the coating film that is uniform and has no defects and in which liquid splash hardly occurs can be efficiently produced.

Claims (5)

[Claims] 1. The outside of the cylinder body is closed by closing one end of the cylinder body whose both ends in the lengthwise direction are open and attaching it to the support member while leaving the other end open, and immersing it in the coating solution from the opened end side and pulling it up. In producing a tubular body having a coating film on its part, when pulling up the tubular body from the coating liquid, most of the tubular body is pulled up at high speed, and the remaining portion is pulled up at low speed. A method for manufacturing a cylinder having the same. 2. The method for producing a cylinder having a coating film according to claim 1, wherein the low speed is set to 50 mm / min or less. 3. The method for producing a cylinder having a coating film according to claim 1 or 2, wherein the remaining portion is 30 mm or less. 4. A cylindrical electrophotographic photosensitive member support whose both ends in the lengthwise direction are open is closed at one end and is attached to a support member while leaving the other end open. When producing a support for electrophotographic photoreceptor having a photosensitive coating film on the outer side of the support by immersing and pulling up, when pulling up the support from the photosensitive coating solution, the portion of the image forming site is pulled up at a high speed, A method for producing a support for an electrophotographic photoreceptor having a photosensitive coating film, characterized in that the non-image forming portion is pulled up at a low speed. 5. The method for producing a support for an electrophotographic photosensitive member having a photosensitive coating film according to claim 4, wherein the low speed is 50 mm / min or less.