JPH0427569Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Field of Application] The present invention relates to an apparatus for applying paint onto the surface of a substrate, and particularly to a coating apparatus for applying paint to a plurality of substrates. Such a coating device is suitably used, for example, to coat a paint containing a photosensitive material onto a cylindrical substrate when manufacturing a photosensitive drum for an electrophotographic device. [Prior Art] Photosensitive drums used in electrophotographic devices are manufactured by forming a photosensitive layer on the surface of a cylindrical base made of aluminum or the like. The direction of formation of the photoreceptor layer on the substrate surface is as follows:
There are vapor deposition methods and coating methods, but the coating method is advantageous in terms of simplicity. Application methods include spray coating, flow coating, dip coating, and coal coating. Among these methods, the dip coating method
The desired film thickness can be easily obtained by adjusting the coating speed (pulling speed), etc., the coating device has a simple configuration, and one device can coat multiple substrates simultaneously. There are advantages. FIG. 3 is a schematic perspective view showing an example of a conventional coating apparatus using the dip coating method. In FIG. 3, 2 is a coating tank, and an inclined plate 4 and six overflow walls 6 are attached to the upper part of the coating tank. 8 is a paint tank;
10 is a pipe for supplying paint from the paint tank to the lower part of the coating tank 2, and a pump 12 and a flow rate control valve 14 are installed in the middle of the pipe. On the other hand, a paint outlet 1 extends through the coating tank wall corresponding to the lowest position of the inclined plate 4.
Two 6's are formed. 18 is a pipe for recovering overflow paint from the two outlet ports to the paint tank 8. Reference numeral 20 is a cylindrical base body, and 22 is a holder for holding the base body together in a predetermined posture, and the holder can be moved in the vertical direction by an elevating means (not shown). During coating, the valve 14 is opened and the pump 12 supplies the paint in the paint tank 8 into the coating tank 2. In the coating tank, the paint gradually rises and overflows from the overflow wall 6. The overflow paint is then collected into the paint tank 2 through the outlet 16 and the pipe 18. In this state, the substrate holder 22 is moved downward, the substrate 20 is immersed in the paint in the coating tank 2 through the opening of the overflow wall 6, and then the substrate holder 22 is moved upward to a predetermined position. is pulled up at a speed of According to the conventional equipment described above, the paint is not simply stored in the coating tank, but is equipped with a paint circulation means, which prevents the occurrence of viscosity difference between the upper and lower parts of the coating tank due to the volatilization of the paint solvent. When a dispersion type paint is used, it is possible to suppress as much as possible the occurrence of causes of uneven coating film thickness such as pigment sedimentation and changes in rheological properties over time. [Problems to be solved by the invention] However, when coating multiple substrates in one coating tank, as in the apparatus shown in Fig. 3 above, the flow rate of the paint may vary depending on the location in the coating tank. Because of these differences, coating is not necessarily carried out under the same conditions for all substrates, resulting in differences in coating thickness between substrates. In the case of manufacturing photosensitive drums for electrophotography, if the above-mentioned variations in coating film thickness occur, the characteristics of the photosensitive drum will significantly deteriorate, resulting in a defective product. The present invention was developed in view of the above circumstances, and is intended to provide a coating device that can apply paint to all substrates with sufficient uniformity in a coating device that applies paint to multiple substrates. The purpose is to provide. [Means for Solving the Problems] According to the present invention, the above object is to provide a coating device in which coating is applied to a plurality of substrates in a coating tank, so that the coating tank can perform independent coating for each substrate. This is achieved by a coating device, characterized in that it has a chamber. [Embodiments] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an embodiment of a coating device according to the present invention, and FIG. 2 is a cross-sectional view of the coating device in a state of use. In these figures, the same members as in FIG. 3 above are given the same reference numerals. This embodiment is an example in which the present invention is applied to coating a photosensitive material onto a cylindrical substrate when manufacturing a photosensitive drum for an electrophotographic device. In FIGS. 1 and 2, 2 is a coating tank, and the coating tank is partitioned into a plurality of (six in the figures) coating chambers 2a by vertical partition walls 3. Each coating chamber 2a has an inclined plate 4 attached to its upper part, and the inclined plate is further provided with a hollow cylindrical overflow wall 6 extending upward from an opening formed in the center thereof. Reference numeral 8 denotes a paint tank containing a paint containing a photosensitive material for electrophotography. 10-1 is a pipe for supplying paint from the paint tank to the lower part of the coating tank 2, and a pump 12 is installed in the middle of the pipe. The pipe 10-1 is branched into two pipes 10-2 and 10-3, and flow control valves 14-1 and 14-2 are installed in the middle of these pipes, respectively. The above pipe 10-2 branches into three pipes 10-4 and 1
0-5, 10-6, and flow control valves 14-3, 14-6 are installed in the middle of these pipes, respectively.
4, 14-5 are attached. The pipes 10-4, 10-5, and 10-6 are connected to the lower part of each separate coating chamber 2a. Although not shown, the pipe 10-3 is also branched like the pipe 10-2 and connected to separate coating chambers via respective control valves. As shown in FIG. 2, a means for rectifying the inflowing paint is provided at the lower part of each coating chamber 2a. The rectifying means is a baffle plate 1
1-1 and a perforated plate 11-2. On the other hand, a paint outlet 16 is formed through the wall of the coating tank 2 corresponding to the lowest position of the inclined plate 4 attached to each coating chamber. Each outlet has piping 18-1, 18-2, 18-3, 1 for returning overflow paint to the paint tank 8.
8-4, 18-5, and 18-6 are connected.
The pipes 18-1, 18-2, and 18-3 merge to form a pipe 18-7, and similarly the pipe 18-
4, 18-5, 18-6 merge to pipe 18-8
Both of these pipes 18-7 and 18-8 are connected to the paint tank 8. 20 is a cylindrical base made of aluminum, for example. Reference numeral 22 denotes a holder for holding the base body together in a predetermined posture, and the holder can be moved in the vertical direction by an elevating means (not shown). The base body 20 is arranged facing in the vertical direction corresponding to the arrangement of the coating chamber 2a. Next, the operation of this embodiment will be explained. First, the control valve attached to each paint supply side pipe is opened to an appropriate opening degree, and the paint in the paint tank 8 is supplied to the lower part of each coating chamber 2a by the pump 12, and the paint overflows evenly from the overflow wall 6 to the surrounding area. Then, the overflow paint is collected into the paint tank 8 through the paint recovery side piping. Next, the base body holder 22 is
is moved downward, and each substrate 20 is immersed in the paint in the coating chamber 2a. Figure 2 shows this situation,
Arrows indicate paint flow. After maintaining the state shown in FIG. 2 for a predetermined time as described above, the holding body 22 is moved upward at a predetermined speed by a lifting means (not shown),
As a result, the substrate 20 whose surface is coated with paint is lifted out of the coating chamber 2a. In the present embodiment described above, the paint flowing into each coating chamber 2a is made into a substantially uniform flow by the rectifying means and flows upward, and is further uniformly distributed from the overflow wall 6 whose surroundings are at substantially the same height. Because of the overflow, the paint flows at a substantially uniform flow rate to all positions on the surface of the immersed substrate 20, thus forming a coating layer with extremely good thickness uniformity on the surface of the substrate. Such good coating is achieved in the same way in all coating chambers 2a, and therefore a coating film of uniform thickness is formed on all substrates. Next, a comparison will be made between the case where paint is applied using the apparatus of the above embodiment and the case where paint is applied using the conventional apparatus shown in FIG. 3 above. As the paint to be applied, 10 parts of hydrazone dye,
A paint (viscosity: 170 cps) consisting of 10 parts of polymethyl methacrylate and 70 parts of monochlorobenzene was used.
Furthermore, a cylindrical body (diameter 100 mm, length 300 mm) made of aluminum was used as the base. Also,
The coating speed (pulling speed) is 100mm/min.
Six substrates were coated simultaneously. After applying the paint, the paint was dried and the thickness of the paint film was measured. The measurement results are shown in Table 1. Note that the results indicate the average film thickness for each sample.

[Table] From the above results, when using the conventional device, the variation in the coating film between each sample was 1.4μm, whereas when using the device of this example, the variation in the coating film between each sample was 1.4 μm. It can be seen that the variation is 0.3 μm, which indicates that sufficiently good paint application is possible. Although the above embodiment shows an example in which six coating chambers are arranged in the coating tank, the present invention does not particularly limit the number of coating chambers as long as they are plural. Furthermore, although the above embodiments have been described with respect to the application of a paint containing a photosensitive material when manufacturing a photosensitive drum for an electrophotographic apparatus, the present invention is not limited thereto, and can be applied to other appropriate paint applications. [Effects of the invention] According to the invention as described above, paint can be applied simultaneously to a plurality of substrates with sufficient uniformity.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a coating device according to the present invention, and FIG. 2 is a cross-sectional view of the coating device in its use state. FIG. 3 is a schematic perspective view showing a conventional coating device. 2... Coating tank, 2a... Coating chamber, 3... Partition wall,
4... Inclined plate, 6... Overflow wall, 8...
Paint tank, 11-1... Baffle plate, 11-2...
Perforated plate, 16... Paint outlet, 20... Substrate, 2
2...Base holder.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A coating device that applies paint to a plurality of substrates in a coating tank, characterized in that the coating tank has an independent coating chamber for each substrate. . (2) The coating device according to claim 1 of the utility model registration claim, in which each coating chamber is provided with a paint circulation means. (3) The paint circulation means includes a paint tank, means for supplying paint from the paint tank into each coating chamber, and means for collecting overflowing paint from each coating chamber into the paint tank, and The coating device according to claim 2 of the utility model registration claim, wherein the coating device is shared by all coating chambers. (4) The coating device according to claim 2 of the utility model registration claim, wherein a rectifying means is provided in the coating chamber.