JPS6283069A - Coating method - Google Patents

Abstract

PURPOSE:To form an excellent film enhancing the slip property between a cylindrical body and a shielding member, in a vertical type coating method, by rotating the cylindrical body around the axis thereof during the application of a coating solution. CONSTITUTION:A coating solution 4 is preliminarily housed in a concave coating solution storing part 13 formed around the cylindrical body 1 inserted in the opening of a shielding member 8 by the shielding member 8 and a short cylindrical member 9. When the cylindrical body 1 is upwardly moved in this state while rotated around a support shaft 5 to form a film 15, the slip property between the shielding member 8 and the cylindrical body 1 is enhanced and, therefore, the thickness of the film 15 becomes uniform and the film having no pinhole is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a coating method for an image holding member, and more particularly to a coating method for forming a coating film of a uniform and constant thickness on the entire outer peripheral surface of a cylindrical body.

(B) Conventional technology Conventionally, methods for applying a coating material to a cylindrical body include a spray method, and a method in which a ring-shaped coating liquid storage part is provided around the outer periphery of the cylindrical body coaxially with the cylinder axis of the cylindrical body. A vertical coating method in which either the cylindrical body or the coating liquid storage part is completely moved to apply the coating, a dipping method in which the cylindrical body is immersed in a dipping tank and the cylindrical body is pulled up, or the liquid is drained from the dipping tank are known. It is being

(c) Problems to be Solved by the Invention However, although the above-mentioned spraying method is excellent in mass production, it has drawbacks such as a small amount of coating per application and poor surface smoothness.

The dipping method has simple equipment and can be applied neatly to any shape of coating member (hereinafter referred to as the substrate), but it has the disadvantage of requiring a large amount of coating liquid when coating a long object.
Further, when the substrate is swollen or eroded by the solvent in the coating solution, there are problems in that not only a uniform film thickness cannot be obtained, but also residual solvent is trapped in the substrate even after drying.

On the other hand, the vertical coating method has excellent surface smoothness of the coating film, and even when coating a long object, the capacity of the coating liquid storage section can be freely changed according to the substrate, so that the coating liquid can be coated easily. It can be applied in a very small amount. Furthermore, because the contact time between the substrate and the coating solution is short, multilayer coating with the same solvent system is possible, and even if the substrate is swollen or eroded by the solvent in the coating solution, it is possible to coat the substrate in multiple layers compared to the dipping method. It has the advantage that the film thickness is uniform and the amount of residual solvent after drying is so small that it is not a problem.

However, in the vertical coating method, since the lower end of the space between the coating liquid storage part and the outer circumferential wall of the cylindrical body is sealed with a shield member, the cylindrical body and the shield member are separated when being pulled up or down. The slipperiness of the material becomes a problem. In particular, if the hole diameter of the shield member is small and the surface of the cylindrical body is not smooth, the lifting or lowering speed may fluctuate, the shield member may flap, and horizontal stripes or bubbles may appear on the coating film. Such problems were occurring. For this reason, the surface roughness of the coating film was rough, the film thickness varied widely, and many pinholes were generated.

The present invention was made in view of the above circumstances, and aims to provide a coating method that improves the vertical coating method and provides a coating film with uniform thickness, excellent smoothness, and no pinholes. It is something.

B.) Means for Solving the Problems The present invention provides a short cylindrical member having an inner diameter larger than the outer diameter of the cylindrical body, which is provided substantially coaxially with the cylinder axis of the vertical cylindrical body, and the short cylindrical member. A coating liquid is stored in a coating liquid storage area formed around the cylindrical body by a shield member that seals the lower end of the space between the cylindrical body and the outer peripheral wall of the cylindrical body. Application in which a coating film is formed on the outer peripheral wall of the cylindrical body by moving only the body upward, by moving only the short cylindrical member downward, or by moving the cylindrical body upward and the short cylindrical member downward. In this method, a cylindrical body is rotated about a cylinder axis during application of a coating liquid.

(E) Function The present invention improves the sliding property between the cylindrical body and the shield member by rotating the cylindrical body around the cylinder axis during application of the coating liquid.

(f) Examples The present invention will be described in detail below based on examples shown in the figures. Note that the present invention is not limited to this.

FIG. 1 is an enlarged cross-sectional view of essential parts showing an example of a Z coating device used in carrying out the present invention.

In the figure, (1) is a vertical cylindrical body, (2) is a lid plate that is fixed to the opening at both ends of the cylindrical body (1) and closes the opening; An arm (3) that moves up and down is provided, and the arm (3) passes through both lid plates (2) and nuts (4) are attached to the lid plates (2) at two upper and lower locations.
A support shaft (5) fixed at is attached.

Here, the support shaft (5) is rotatable, and at the same time, the cylindrical body (1) also rotates.

Around the cylindrical body (1), there is a cylindrical body (1)'! A plate-shaped horizontal member having an insertion hole (6) for insertion into the
The force is provided to be movable in the vertical direction. Horizontal member (
7) A sheet-like shield member (8) is placed on the upper surface, and the center part of the shield member (8) has a diameter smaller than the outer diameter of the cylindrical body (1) by about 0.1 mu to 5 cTL. A diameter opening (not shown) is provided. Note that the center of the opening of the shield member (8) is located at the insertion hole (6).
The cylindrical body (1) is placed so as to coincide with the cylindrical axis of the cylindrical body (1). Further, a short cylindrical member (9) having an inner diameter larger than the outer diameter of the cylindrical body (1) is attached to the horizontal member (7) via the shield member (8), and a short cylindrical member (9) is inserted into the insertion hole (6). Coaxially with the cylindrical axis of the shaped body (1), fix the downward-pointing cylindrical fixing jig θ0, pol) (11) and naso) (12).
It is fixed by 1. This fixes the shield member (8).

The material of the shield member (8) may be flexible and stable against the solvent of the coating liquid, preferably having good slip properties. Specific examples include polyethylene, polypropylene, Teflon, polyester,
Examples include silicone rubber and fluororubber, but the present invention is not limited to these. In addition, the thickness of these shield members (8) varies depending on the material, but is 20 μm.
m to 5 mm, preferably 100 (, trrt-1 m
m is good.

Moreover, the rotational speed of the support shaft (5) is angular speed of 0.1 to 10
It is about 0 rad/min.

Next, a method of forming a coating film using the above apparatus will be explained.

First, the cylindrical body (
The concave coating liquid storage part (131) formed at the four corners of 1) stores the coating liquid α4′ft, and then the cylindrical body (1)
1'! The coating film (15+) is formed by moving it upward while rotating it around the support shaft (5).

In this way, since the cylindrical body (1) is moved upward while fully rotating, the shield member (8) and the cylindrical body (1)
This improves the slipperiness of the film, resulting in uniform film thickness.

Surface roughness can be improved.

In addition, in the above method, the cylindrical body (1) is completely pulled up to form a coating film, but in addition, the cylinder-shaped body (1,) is fixed and the horizontal member (7) is pulled down to form a coating film. Alternatively, the cylindrical body (+) may be placed above the horizontal member (
7) may be moved downward to form a coating film.

The method of the present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 and Comparative Example 1 In the apparatus shown in FIG. 1: Diameter of opening of shield member (8) 74 mrn Pulling speed of cylindrical body (1) 7 cm/min Angular velocity of support shaft (5) 3-6 rad/ A soft drum α0 as shown in Fig. 2 was prepared using the following coating solution.
The coating was applied to the outer peripheral wall of.

In FIG. 2, αη is an aluminum pipe, and (1□□□ is a urethane rubber layer cast on the aluminum pipe.

The outer diameter of the aluminum pipe is 74mm, the length is 340WL The outer diameter of the T urethane rubber layer is 79mm, and the thickness is 2.5mm +
The length was 30 cIrL.

Coating liquid: Polyurethane resin 10 parts by weight (solid content 249%) Carbon blank preliminary dispersion liquid 20 parts by weight (solid content
35.3%.

Carbon black/binder (urethane) ratio = 0.37) Methyl ethyl ketone 70 parts by weight Dry solids 10% Viscosity 50 cps The above formulation was stirred for 10 minutes, then left to stand for 10 minutes to defoam and prepare the coating liquid. did.

As a comparative example, a coating was created using the same coating liquid as in the example without rotating the support shaft (5) completely. Table 1 shows the results of measuring the film thickness and surface roughness of the obtained coating film.

Table 1 The surface roughness is the average roughness of 10 points.

From Table 1, the uniformity of the film thickness when the support shaft (5) was coated while being fully rotated was compared to that when it was coated without rotating.
It is clear that the surface smoothness is excellent. In addition, a large number of pinholes were generated in Comparative Example 1, but Example 1
No pinholes were seen.

Example 2 and Comparative Example 2 Using the same equipment and coating metal as in Example 1, all coatings were carried out on the outer peripheral wall of the soft drum (16) shown in FIG. However, the diameter of the opening of the shield member (8) is 78 mm. In Figure 2, αη is an aluminum pipe (in Japan, it is a urethane rubber layer cast on an aluminum pipe. The outer diameter of the aluminum pipe is 74 mm + the length is 34 crtt + the outer diameter of the urethane rubber layer is 84 mm). mrn + thickness is 5mi +
The length was 30 crrL.

Moreover, the pulling speed of the cylindrical body (1) is 15 cIn/
The angular velocity of the support shaft (5) at min is 12 rad/Fr+i
n, and as a comparative example, coating was carried out without fully rotating the support shaft (5). The thickness and surface roughness of the resulting coating film were measured and the results are shown in Table 2.

Table 2 The surface roughness is the average roughness of 10 points.

From Table 2, the uniformity of the film thickness is higher when the support shaft (5) is coated while being fully rotated than when it is coated without rotation.
It is clear that both surface smoothness is excellent. Furthermore, in Comparative Example 2, the pulling speed during coating fluctuated considerably and there were also bumps.

The coating material used in the method of the present invention is not limited to those described in the examples, and any known photoconductive material, insulating material, or conductive material can be coated. For example, photoconductive materials include phthalocyanine, ZnO, CdS, TiO,,
Examples include known organic and inorganic materials such as PVK, TNF, and azo pigments. Insulating materials that can be used in combination with these or used alone include polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, polyester,
(Meth)acrylic, polyvinylpyrrolidone, methylcellulose, hydroquinepropylmethylcellulose, polyvinylbutyral, polyimide, polyamideimide, polyarylate, polysulfone, polyamide, fluororesin,
A polymer resin such as polyurethane is used.

In addition, as conductive materials, carbon blank, Ketjenblack, tin oxide, indium oxide, antimony trioxide, zinc oxide, titanium black, potassium titanate, etc. are used in combination with the insulating substances listed above. . Also, an insulating resin alone can be used.

(G) Effects of the Invention According to the present invention, a coating film having a uniform thickness and smoothness can be formed.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of an example of a coating apparatus used to carry out the coating method of the present invention, and FIG. 2 is an enlarged cross-sectional view of a cylindrical body of another example of the apparatus. (1)...Cylindrical body, (6)...
Insertion hole, (7)...Horizontal member, (8)...
... Shield member, (9) ... Short cylindrical member,
α3)... Coating liquid storage section, (14)...
...Coating liquid, (151...Coating film. (2)...Lid plate, (3)...Arm, (4)...Nut , (5)...Support shaft, (10)...Fixing jig, 01)...
...Boruto, (12) ...Natsuto, 06)
... Soft drum, (17) ... Aluminum pipe, 0 barrel ... Urethane rubber layer. Patent applicant: Yuo Issel Chemical Industry Co., Ltd. Representative: Patent attorney: Takashi Koshiba Figure 1

Claims (1)

[Claims] 1. A short cylindrical member that is provided approximately coaxially with the cylinder axis of the vertical cylindrical body and has an inner diameter larger than the outer diameter of the cylindrical body, and a space between this short cylindrical member and the outer peripheral wall of the cylindrical body. Store the coating liquid in the coating liquid storage area formed around the cylindrical body by the shield member that seals the lower end of the cylindrical body, and move only the cylindrical body upward, or move only the short cylindrical body. In a coating method in which a coating film is formed on the outer circumferential wall of a cylindrical body by moving the short cylindrical member downward or moving a short cylindrical member that extends above the cylindrical body downward, the cylindrical body is moved during application of the coating liquid. A coating method characterized by rotation around a cylinder axis.