JPS6254065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method, and more particularly to a coating method for a coated object having an internal space.

Coating by dipping has been widely practiced. The method basically involves placing the object to be coated in the paint, and then drawing the object out of the solution at an appropriate speed to apply the paint to its surface. In the case of coating by the dipping method, a uniform coating film can be obtained by appropriately setting the coating conditions such as the viscosity of the coating material and the pulling speed according to the shape of the object to be coated.

In this coating method, when the object to be coated is cylindrical and hollow inside, such as an electrophotographic photosensitive drum, it is necessary to prevent the paint from adhering to the inside of the object. It is. To prevent this, it is necessary to close the internal space of the object to the paint by, for example, closing the lower end or the upper end of the object. However, the method of coating by closing the bottom end of the object to be coated using some kind of auxiliary device such as a bottom lid does not allow for the generation of air bubbles caused by the auxiliary device.
It is easy to cause defects in the coating film due to uneven thickness due to differences in level with the object to be coated, and dust generation from the coating film due to attachment/detachment.Additionally, it is necessary to prepare auxiliary equipment for the number of coats to be coated, and even if the auxiliary equipment is reused, it will not stick to the auxiliary equipment. The coating film must be washed and removed, which poses a problem in terms of productivity.

On the other hand, the method of coating by closing the upper end of the object to be coated solves the above-mentioned drawbacks, but due to the slight temperature difference between the paint and the outside air, the air inside the object to be coated may expand or The solvent in the paint evaporates inside the object and the volume increases, often causing bubbles to form from below during lifting. When such bubbles appear, the paint shakes significantly, causing unevenness on the coated surface and hindering the formation of a uniform paint film.

Therefore, the main object of the present invention is to provide a coating method that is good for preventing excessive penetration of paint into the hollow interior of a cylindrical object and for forming a uniform coating film when coating a cylindrical object. .

In the coating method according to the present invention, a part of the cylindrical object to be coated, which is open at both ends, is dipped into the paint, so that the paint penetrates into a part of the inside of the object to be coated, and then the inside of the object to be coated is coated. The method is characterized in that the entire object to be coated is immersed in the paint in a sealed space, and then removed from the paint.

That is, in the coating method of the present invention, a part of the cylindrical object to be coated is immersed in the paint to replace a part of the air inside the hollow part of the object with the paint, and then the object to be coated is sealed. By applying the coating by dip coating, even if the internal pressure of the object to be coated becomes higher than the external pressure, bubbles will not be released from the inside into the paint, thereby improving the precision of the coating.

1 to 3 show one embodiment of the coating method according to the present invention.

In FIG. 1, an object to be coated 1 is a base of a photoreceptor used in an electrophotographic copying machine, and is made of cylindrical aluminum and has a space open at both ends. Reference numeral 2 denotes a holder at the upper end of the object to be coated 1, which is connected to an elevating device through a support rod 3 to perform dip coating operations. The valve 4 can be opened and closed to allow the gas inside the object 1 to flow out. The O-ring 5 is used to prevent gas from flowing out from the O-ring by pressing the holder 2 against the inner surface of the object 1 to be coated.

Figure 2 shows that by immersing the object 1 to be coated into the paint 6 in the coating tank 7 with the valve 4 open, the gas inside the object flows out through the valve 4 and at the same time some of the paint infiltrates. It shows the condition. FIG. 3 shows a state in which the valve 4 is closed after a certain amount of gas has flowed out in FIG. 2, and the object to be coated is immersed in the paint in the closed state.

Next, by lifting the object to be coated from the state shown in FIG. 3 at a speed suitable for coating, the paint can be evenly applied to the surface of the object.

[Brief explanation of the drawing]

FIG. 1 is a side view of a state in which a support is attached to an object to be coated. FIG. 2 is a side view of the partially submerged state with the valve open. FIG. 3 is a side view of a state in which the valve is closed and immersed. 1: Object to be coated, 2: Holder, 3: Support rod, 4:
Valve, 5: O-ring, 6: Paint, 7: Application tank.

Claims (1)

[Claims] 1 After immersing a part of the cylindrical object with both ends open in the paint, the paint penetrates into a part of the inside of the object. A coating method characterized by immersing the entire object to be coated in the paint and then removing it from the paint.