JPS6145503B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method using a screen.

Conventional coating methods include dipping, spraying,
There are roll methods, etc. However, since the dipping method involves dipping the member to be coated into the paint and pulling it up to apply the coating, it requires a much larger amount of paint than is actually applied, and it also requires repeated use of the same paint. Therefore, the pot life of the paint must be long. Therefore, when using the dipping method, large-scale equipment is required to keep the composition of a large amount of paint constant at all times, and the type of paint is also limited. In order to form a uniform coating film, the pulling speed must be as slow as possible, resulting in very low work efficiency.

In addition, when using the spray method, the paint can be used once, but the application conditions vary greatly depending on the environmental temperature, so large-capacity air conditioning is required.
Like the dipping method, the working efficiency is low, and furthermore, the coating film formed tends to vary.

Furthermore, in the case of coating by a roll method, it is difficult to form a uniform coating layer unless the member to be coated is a horizontal surface.

Therefore, the main object of the present invention is to provide a coating method that is easy to operate, has excellent manufacturing efficiency, and can form a uniform coating film.

The coating method according to the present invention is characterized in that the coating material is applied to the member to be coated through a screen provided with a cover.

That is, according to the coating method of the present invention, the coating material is applied onto the member to be coated through the mesh of the screen, and the amount of coating material used does not need to be small, and the composition of the coating material can be easily maintained and controlled. , and the production efficiency of the coating film is high. Furthermore, by adjusting the mesh size of the screen, a uniform coating film of a predetermined thickness can be easily formed with good reproducibility. Moreover, when the member to be coated is drum-shaped, a seamless coating film can also be easily produced. Furthermore, when coating through a screen, it is desirable that the viscosity of the coating material be kept constant during the coating process. This is because the mesh of the screen is usually very small, so if the paint solvent evaporates too much during the coating operation and becomes highly viscous, it may not be able to pass through the screen, it may clog the screen, or it may become viscous. This is because inconvenient phenomena such as sticking occur. However, in the present invention, since the screen is provided with a cover, the evaporation of the paint solvent can be prevented, so that the above-mentioned disadvantageous phenomenon does not occur. It is also possible to prevent dust from entering from the outside. Further, by introducing solvent vapor into the cover as necessary, the viscosity of the paint can be actively adjusted. As a screen, 10~
One having 1000 meshes, and sometimes 100 to 600 meshes, is preferably used.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows one embodiment of the coating method according to the present invention, in which a screen 2 is placed on a member 1 to be coated. A paint 4 is placed on the screen 2, and is squeezed by a blade 3 so that the paint passes through the screen and is applied to the member 1 to be coated to form a coating film 8. The screen 2 is provided with a bellows 5 fixed to a bellows fixing member 9 as a cover. The tip 20 of the bellows 5 is the blade 3
Fixed. The screen 2 is fixed to a screen frame 10. During the coating operation, the blade 3 and the member to be coated 1 do not move (however, the member to be coated rotates in the direction of arrow 7), and the screen 2 moves in the direction of arrow 6.
move in the direction of Since the bellows fixing member 9 is fixed to the screen frame 10, the bellows fixing member 9 also moves together with the screen 2. In this way, the paint 4 is applied by the blade 3. FIG. 1 (as well as FIGS. 2, 3 and 4) shows an intermediate state in the coating process, in which the screen 2 has moved half the distance and the coating 8 has also been covered. It is formed on half of the surface of the application member. The paint 4 is placed inside the box, the screen 2 is placed on the bottom of the box, the bellows 5 is placed on the top, and wall plates (not shown) are provided on the front and back sides of the box. ing. In this way, evaporation of the paint solvent is minimized and the paint viscosity remains constant.

FIG. 2 shows another embodiment of the present invention, in which a blind cover 11 is provided as a cover for the screen 2. 12 is a cover fixing member. The blind cover 11 is fixed to the blade 3 at a tip 21. Other configurations and operating methods are the same as those shown in FIG.

FIG. 3 shows still another embodiment of the present invention, in which an elastic sheet 13 such as a rubber sheet is used as a cover, the tip 22 of the elastic sheet 13 is fixed to the blade 3, and the elastic sheet 13 is It is fixed by a sheet fixing member 14. Other configurations and coating operation methods are the same as those shown in FIG.

FIG. 4 shows still another embodiment of the present invention, in which a bellows 15 is further provided as a lower cover in addition to the embodiment shown in FIG. The bellows 15 is fixed by bellows fixing members 9 and 16. By doing so, evaporation of the solvent from below the screen can be considerably prevented, which is even better. In addition, as a means for rubbing the paint used in the present invention,
In addition to the above-mentioned blade, any other rubbing means can be used, such as a sponge roller, a rubber roller, or a plate that can sequentially press the screen surface. Also,
During coating, it is advantageous to move the screen for operational purposes, but it is also possible to fix the screen and move the squeezing means and the member to be coated (if the member to be coated is flat, the squeezing means alone may be used). Furthermore, the screen, the squeezing means, and, if necessary, the member to be coated can be moved relative to each other for coating.

Various types of articles can be arbitrarily employed as the member to be coated, and a typical example thereof is an image holding member used in electrophotography. The image holding member has an insulating layer or a photoconductive layer on its surface, and the uniformity of these layers significantly affects the image forming ability. Therefore, the coating method according to the present invention is most effectively applied. This is one possible example. Image holding members on which electrostatic images or toner images are formed by electrophotography include image holding members having a photoconductive layer and image holding members not having a photoconductive layer, which are called electrophotographic photoreceptors. It consists of a support and an image-retaining layer on it.

Electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on the type of electrophotographic process to which they are applied. Typical electrophotographic photoreceptors include photoreceptors in which a photoconductive layer is formed on a support, and photoreceptors in which a photoconductive layer is laminated with an insulating layer thereon, which are widely used. . A photoreceptor composed of a support and a photoconductive layer is used for image formation by most common electrophotographic processes, ie, charging, image exposure and development, and optionally transfer. In addition, the insulating layer in a photoreceptor equipped with an insulating layer is used for purposes such as protecting the photoconductive layer, improving the mechanical strength of the photoreceptor, improving dark decay characteristics, or being applied to a specific electrophotographic process. Typical examples of photoreceptors having such an insulating layer or electrophotographic processes using such a photoreceptor having an insulating layer include, for example,
U.S. Patent No. 2860048, Japanese Patent Publication No. 16429, Japanese Patent Publication No. 15446, Japanese Patent Publication No. 15446, Japanese Patent Publication No. 3713, Japanese Patent Publication No. 42, Japanese Patent Publication No. 23910, Japanese Patent Publication No. 24748, Japanese Patent Publication No. 1977.
Publication No. 19747, Special Publication No. 19747, Special Publication No. 1974-
It is described in Publication No. 4121, etc. In addition, there are also image holding members having only an insulating layer without a photoconductive layer, and some typical uses of this image holding member will be described below.

(1) For example, Special Publication No. 7115, Special Publication No. 32-
As described in Publication No. 8204 and Japanese Patent Publication No. 43-1559, electrostatic images formed on electrophotographic photoreceptors without a photoconductive layer are used for the purpose of improving the repeatability of electrophotographic photoreceptors. The toner image is transferred to an image holding member and developed, and then the toner image is transferred to a recording medium.
An image holding member used in this electrophotographic process.
(2) In addition, as another electrophotographic process in which an electrostatic image is formed on an image holding member without a photoconductive layer in correspondence with an electrostatic image formed on an electrophotographic photoreceptor, for example, Japanese Patent Publication No. 45-30320 As described in Japanese Patent Publication No. 48-5063, Japanese Patent Application Laid-open No. 51-341, etc., a screen-shaped electrophotographic photoreceptor having many minute openings is coated with a predetermined electrophotographic process. By applying corona charging to an image holding member that does not have a photoconductive layer through this electrostatic image, the ion flow of the corona is modulated to form an electrostatic image that does not have a photoconductive layer. An example of this process is to form a final image on a non-containing image holding member, develop it with toner, and transfer it to a recording medium. Examples include image holding members used in this electrophotographic process.

A typical structure of an electrophotographic photoreceptor having an insulating layer is a support made of copper, stainless steel, aluminum, etc.
It is a laminate including a photoconductive layer and an insulating layer. The photoconductive layer is ZnO, CdS, CdSe, TiO ₂ , ZnS, ZnSe,
It is formed by laminating, vapor depositing, sputtering, coating, etc. an organic semiconductor such as Se, Se-Te, Se-Te-AS, or polyvinyl carbazole, alone or together with a binder resin. Although the thickness of the photoconductive layer depends on the type and characteristics of the photoconductive material used, it is generally preferred to have a thickness of about 5 to 100 .mu.m, particularly about 10 to 50 .mu.m.

Generally, when an insulating layer is added for the main purpose of protecting the photoconductive layer, improving its durability and dark decay characteristics, the insulating layer is set relatively thin, and the insulating layer is set relatively thin when used for a specific electrophotographic process. The layer is set relatively thick.

Usually, the thickness of the insulating layer is 5 to 70μ, especially 10 to 70μ.
Set to 50μ.

As the binder resin of the photoconductive layer and the resin used to form the insulating layer, various ordinary insulating resins can be used as appropriate. Examples include polyethylene, polyester, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, acrylic resin, polycarbonate, silicone resin, fluororesin, and epoxy resin.

Example 1 1-phenyl-3- as an organic photoconductor material
(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline 10g, purified β-type copper phthalocyanine manufactured by Toyo Ink.
8 g, 10 g of polyester resin (manufactured by Toyobo, trade name: Vylon) and 40 g of MEK were mixed, and the mixture was treated with a Red Devil disperser for 2 hours.

Using this coating solution, a #150 screen plate was used to coat an aluminum drum substrate with a diameter of 80 mm and a length of 345 mm using the usual screen printing method, dried at 80°C for 20 minutes, and coated with a thickness of 7 μm. A seamless photoreceptor was created. When five drums were applied in succession, the coating surface of the fifth drum was highly rough, and uneven coating thickness was observed depending on the location.
In addition, the coating liquid solidified in various parts of the screen, causing clogging.

On the other hand, when coating was carried out by the screen printing method according to the present invention as shown in FIG.
The coating film on the fifth photosensitive drum is uniform and has no roughness.
No unevenness in film thickness was observed. Also, there was no clogging on the screen plate.

Next, when an image was produced using the process of primary charging -5.5KV, exposure, development, and blade cleaning, the comparison sample showed image disturbances corresponding to surface roughness and unevenness, whereas the present invention When a photoreceptor was used, a uniform image was obtained.

[Brief explanation of the drawing]

1, 2, 3, and 4 each illustrate one embodiment of the coating method according to the present invention. DESCRIPTION OF SYMBOLS 1... Member to be coated, 2... Screen, 3... Blade, 4... Paint, 5... Bellows, 8... Paint film, 11...
Blind type cover, 13...Elastic sheet, 15...
Jiyabara.

Claims (1)

[Claims] 1. A coating method characterized in that a coating material is applied to a member to be coated through a screen provided with a cover.