JPS6125659A - Coating device - Google Patents

Abstract

PURPOSE:To coat the outer surface of an object uniformly without the intrusion of the coating liquid into inside of the object by fitting the object to be coated having a hollow liquid-tightly using a float provided with an auxiliary floating device. CONSTITUTION:The object to be coated 2 having a hollow 20 such as a cylindrical drum etc. is supported liquid-tightly by the float 3 through a fitting part 31. As the object 2 is held at the fitting part of the float 31 by buoyancy of the float 3 and own weight of the object 2 liquid-tightly, the intrusion of the coating liquid into inside of the object is prevented. Under this condition, the object to be coated 2 is pushed down smoothly in a receiving tank against the buoyancy of the float 3, and immersed into the coating liquid 11. When the pressure is released slowly, the object 2 ascends in the liquid 11 through the float 3 and the auxiliary floating device 5 that enhances the buoyancy of the float, and returns to an original position on the surface of the liquid, and coating is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a dip coating apparatus, and more particularly, to a coating apparatus that can uniformly coat the outer surface of a hollow object to be coated without allowing a coating liquid to penetrate into the hollow space. Regarding.

(Prior Art) In the dip coating method in which a hollow object to be coated, such as a cylindrical drum, is immersed in a coating liquid and its outer peripheral surface is coated, it is necessary to prevent the coating liquid from penetrating inside the drum. In this method, as shown in FIG. 7, a lid 201 is provided at the bottom of the drum 200. However, in order to continuously coat the drum 200, attaching and detaching the lid 201 requires time and effort. Furthermore, it is necessary to clean the lid 201 every time the process is completed.

Therefore, the coating operation is extremely inefficient.

(Object of the Invention) An object of the present invention is to provide a coating device that can uniformly coat the outer surface of a hollow object to be coated without allowing the coating liquid to penetrate inside the object. Another object of the present invention is to provide a coating device that is easy to operate and can form a coating layer at low cost.

(Structure of the Invention) The coating apparatus of the present invention is an apparatus for immersing an object to be coated having a hollow cavity in a coating liquid in a coating liquid storage tank and applying the coating liquid to the object to be coated. The coating object has a float that engages with the coating object and maintains a liquid-tight state (no liquid infiltration) with respect to the hollow cavity of the coating object, and a support rod that supports the float, This achieves the above objective.

Furthermore, the coating device of the present invention further includes a floating assisting means for assisting the floating of the float, thereby achieving the above object.

(Example) The present invention will be described below with reference to examples.

As shown in FIGS. 1 and 2, the coating device of the present invention has the following features:
It has a coating liquid storage tank l and a float 3 that holds an object 2 to be coated. This storage tank 1 stores coating liquid II. A support rod 4 that supports the float 3 is vertically arranged in the center thereof.

The float 3 supports a coated object 2 having a hollow cavity 20 such as a cylindrical drum through an engaging portion 31 made of, for example, a fluorine-based rubber gasket. This float retaining portion 31 maintains a liquid-tight state with respect to the cavity 20 of the object to be coated. A through hole 32 is provided in the center of the float 3, and the float 3 can slide on the support rod 4 through the through hole 32. For example, a fluororesin gasket is provided near the through hole 32 to hold the float 3 and the support rod 4 in a liquid-tight manner. As the fluororesin packing, one that is insoluble in the coating liquid 11 and has excellent sealing properties, sliding properties, and abrasion resistance may be appropriately selected.

There are no particular restrictions on the shape, volume, or weight of the float 3, and any float 3 can be used as long as it can liquid-tightly seal the cavity 20 of the object to be coated by its own weight and levitate the object 2 to be coated. Bye. It goes without saying that the material is insoluble in the coating liquid 11.

5 for the purpose of increasing the buoyancy of float 3 2 as necessary
Buoyancy aids 5 such as springs or hydraulic or pneumatic cylinders can be provided. This levitation assisting means 5 is 1
For example, in the case of a spring, one end is attached to the float 3 via a support rod 4, and the other end is attached to the inner wall of the storage tank 1. It is necessary that this floating assisting means 5 is not corroded by the coating liquid 11.

The shape of the storage tank 1 is not particularly limited. Its volume is
In order to reduce movement of the coating liquid surface due to taking in and out of the object 2 to be coated, it is preferable that the volume is larger than the external volume of the object 2 to be coated. The material (1) may be any material as long as it is insoluble in the coating liquid 11 (1) Usually, aluminum, stainless steel, synthetic resin, etc. are used.

This storage tank 1 is provided with a coating liquid replenishing means as required.

There are no particular limitations on the cross-sectional shape, cross-sectional dimensions, length, material, etc. of the object 2 to be coated. For example, in the case of a drum used for an electrophotographic photoreceptor, aluminum having a cylindrical shape is used.

Dip coating is applied to the object to be coated 2 using the above-mentioned apparatus in the following manner. First, the object 2 to be coated is as follows.

It is supported by the float 3 via a retaining portion 31 in a liquid-tight manner.

At this time, the object 2 to be coated is held in a liquid-tight manner by the float holding portion 31 by the buoyancy of the float 3 and the weight of the object 2 to be coated. Therefore, the coating liquid 1 is applied inside the hollow object 2 to be coated.
1 is prevented from entering. Then, the object 2 to be coated is smoothly pushed down into the storage tank 1 against the buoyancy of the float 3, and is immersed in the coating liquid 11 in the storage tank 1. Next, when the pressure is gradually released, the object 2 to be coated rises within the coating liquid 11 due to the buoyancy of the float 3 and returns to its original position above the liquid surface. The object to be coated 2 on which the coating layer has been formed is removed from the float 3 . The coating layer of the coated object 2 thus obtained is uniform. By activating the buoyancy assisting means 5 that increases the buoyancy of the float 3, the coating operation can be performed more smoothly and quickly, with less variation between lots. The buoyancy of the float 3 itself can also be small.

Other embodiments of the coating apparatus described above are shown in FIGS. 3 and 4. Here, the float 3 is fixed to a support rod 4, and the support rod 4 can slide through a through hole 12 provided at the bottom of the storage tank 1. A fluororesin gasket is provided near the through hole 12 for the purpose of maintaining the space between the support rod 4 and the storage tank 1 in a liquid-tight state.

This coating device may also include a floating assisting means 5, as shown in FIGS. 5 and 6, to assist the floating of the float 3. In this case, the levitation assisting means 5 is the support rod 4
Any device that supplements the lifting drive of the device may also be used, such as a spring or a hydraulic or pneumatic cylinder.

These flotation assisting means 5 are connected at one end to the support rod 4 and at the other end to an appropriate location outside the storage tank l.

The dip coating operation when using this apparatus is similar to the apparatus shown in FIGS. It is only different from the case of .

The coating apparatus of the present invention is suitably used in fields where extremely fineness and high precision are required, such as the manufacture of photosensitive drums for electrophotography, but it can of course be applied to other fields as well.

(Effects of the Invention) According to the present invention, by engaging the object to be coated in a liquid-tight manner using the float, intrusion of the coating liquid into the inside of the object to be coated is reliably prevented. The coating operation can be performed more smoothly and quickly by using a levitation assisting means that assists the levitation of the float. Since the coating device of the present invention has a simple configuration and is easy to operate, coating can be performed at low cost. Continuous operation is also possible.

[Brief explanation of the drawing]

1 and 2 are front sectional views of essential parts showing one embodiment of the apparatus of the present invention, and FIGS. 3 and 4 are front sectional views of essential parts showing other embodiments of the apparatus of the present invention, respectively. 5 and 6 are front sectional views of main parts showing still other embodiments of the device of the present invention, respectively. FIG. 7 is a front sectional view of a main part showing an example of the prior art. 1, 100... Coating liquid storage tank, 2.200... Object to be coated. 3... Float, 4... Support rod, 5... Levitation assisting means. 11, 110... Coating liquid, 12... Storage tank through hole,
20... Cavity of object to be coated, 31... Float holding portion, 32... Float through hole, 201... Lid. that's all

Claims (1)

[Scope of Claims] 1. In an apparatus for immersing an object to be coated having a hollow cavity in a coating liquid in a coating liquid storage tank and applying the coating liquid to the object to be coated, the object to be coated is the object to be coated. A coating device that includes a float that engages with an object and maintains a liquid-tight state with respect to the cavity of the object to be coated, and a support rod that supports the float. 2. The coating device according to claim 1, wherein the engaging portion of the float with the object to be coated is made of fluororubber. 3. The coating device according to claim 1 or 2, wherein the float slides on the support rod while maintaining a liquid-tight state through a through hole provided in the center of the float. 4. The coating device according to claim 3, wherein the sliding portion of the float with the support rod is made of fluororesin. 5. The coating device according to claim 1 or 2, wherein the support rod slides through a through hole provided at the bottom of the storage tank while maintaining a liquid-tight state. 6. The coating device according to claim 5, wherein a sliding portion of the bottom through hole of the storage tank that slides with the support rod is made of fluororesin. 7. In an apparatus for applying the coating liquid to the object to be coated by immersing the object to be coated having a hollow in the coating liquid in the coating liquid storage tank, the object to be coated engages with the object to be coated and A coating device that includes a float that maintains a liquid-tight state with respect to a hollow cavity of an object to be coated, a support rod that supports the float, and a floating assist means that assists the floating of the float. 8. The coating device according to claim 7, wherein the engaging portion of the float with the object to be coated is made of fluororubber. 9. The coating device according to claim 7 or 8, wherein the float slides on the support rod while maintaining a liquid-tight state through a through hole provided in the center of the float. 10. The coating device according to claim 9, wherein the sliding portion of the float with the support rod is made of fluororesin. 11. The coating device according to claim 9, wherein the floating assisting means is a spring or a hydraulic or pneumatic cylinder that floats the float in the storage tank. 12. The coating device according to claim 7 or 8, wherein the support rod slides through a through hole provided at the bottom of the storage tank while maintaining a liquid-tight state. 13. The coating device according to claim 12, wherein a sliding portion of the bottom through hole of the storage tank that slides with the support rod is made of a fluororesin. 14. The coating device according to claim 12, wherein the floating assisting means is a spring or a hydraulic or pneumatic cylinder that drives the support rod outside the storage tank.