JPH0824868B2 - Method for manufacturing electrophotographic photoreceptor by dip coating - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photosensitive member by applying a coating material on the surface of a substrate, and more particularly to a method for producing an electrophotographic photosensitive member by performing dip coating on a plurality of substrates. . That is, the present invention is suitably used for manufacturing a photosensitive drum for an electrophotographic apparatus by applying a coating material containing a photosensitive material on a cylindrical substrate.

[0002]

2. Description of the Related Art A photosensitive drum used in an electrophotographic apparatus is manufactured by forming a photosensitive layer on the surface of a cylindrical substrate made of aluminum or the like.

As a method for forming the photosensitive layer on the surface of the substrate, there are a vapor deposition method and a coating method, but the coating method is advantageous in terms of simplicity.

As the coating method, there are a spray coating method, a flow coating method, a dip coating method, a roll coating method and the like. Among these, the dip coating method can easily obtain a desired film thickness by adjusting the viscosity, solid content, coating speed (pulling speed) of the coating, and the constitution of the coating device is simple. There is an advantage that it is possible to simultaneously coat a plurality of substrates with one device.

FIG. 3 is a schematic perspective view showing an example of a conventional coating apparatus by the dip coating method.

In FIG. 3, reference numeral 2 is a coating tank, and an inclined plate 4 and six overflow walls 6 are attached to the upper portion of the coating tank. Reference numeral 8 is a paint tank, 10 is a pipe for supplying paint from the paint tank into the lower portion of the coating tank 2, and a pump 12 and a flow control valve 14 are attached in the middle of the pipe. . On the other hand, two paint outlets 16 are formed penetrating the wall of the coating tank at the lowest position of the inclined plate 4. Reference numeral 18 is a pipe for collecting overflow paint from the two outlets to the paint tank 8.

Reference numeral 20 denotes a cylindrical base body, 22 denotes a holding body for holding the base bodies together in a predetermined posture, and the holding body can be moved up and down by an elevating means (not shown). .

At the time of coating, the valve 14 is opened and the pump 12 is opened.
Thus, the paint in the paint tank 8 is supplied into the coating tank 2.
In the coating tank, the paint gradually rises to the overflow wall 6
Overflows. Then, the overflow paint is collected in 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. It is pulled up at a predetermined speed by moving.

According to the conventional apparatus as described above, the paint is not simply stored in the coating tank, but the coating material circulation means is provided, so that the viscosity above and below the coating tank due to the solvent volatilization of the coating material. It is possible to suppress as much as possible the occurrence of differences, the settling of pigments when a dispersion type coating is used, and the occurrence of factors that make the coating film thickness uneven, such as changes in rheological properties over time.

[0011]

However, when coating a plurality of substrates in one coating tank as shown in FIG. 3, there is a difference in the flow velocity of the coating depending on the location in the coating tank. However, the coating material is not always applied under the same condition to all the substrates, and therefore, the coating film thickness varies between the substrates.

In the case of manufacturing a photosensitive drum for electrophotography,
When the above-mentioned variation in coating film thickness occurs, the characteristics of the photosensitive drum are significantly deteriorated, resulting in a defective product.

The present invention has been made in view of the above circumstances, and in a method for producing an electrophotographic photosensitive member by applying a coating material to a plurality of substrates, the coating material is applied to all the substrates with sufficient uniformity. The purpose of the present invention is to produce an electrophotographic photosensitive member having good characteristics by minimizing the variation in coating film thickness.

[0014]

According to the present invention, the above object is to provide a method for producing a plurality of electrophotographic photosensitive drums by dipping coating, wherein a layer containing a photosensitive material is attached to the surface of a cylindrical substrate. the paint containing the photosensitive material from the paint tank to accommodate to a plurality of coating chambers supplying paint independently one said substrate to each coating chamber inlet <br/> is by coating chamber of the coating And the paint overflowed from each coating chamber is collected in the paint tank.

In the present invention, the paint can be rectified in each coating chamber, and the rectification can be performed on the paint supplied from the paint tank to each coating chamber.

The following coating apparatus can be used for carrying out the method of the present invention: (1) In a coating apparatus for coating a plurality of substrates in a coating tank, the coating tank has each substrate. A coating device having an independent coating chamber for: (2) A coating material circulation means is provided for each coating chamber; And a means for supplying paint from the paint tank into the coating chambers and a means for collecting paint overflowing from the coating chambers into the paint tanks, and the paint tank is shared by all the coating chambers. The coating apparatus according to the above (2); (4) The coating apparatus according to the above (2), wherein a rectifying means is provided in the coating chamber.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing an embodiment of a coating apparatus used for carrying out the method of the present invention, and FIG. 2 is a sectional view taken along the line II-II in the usage state. In these figures,
The same members as those in FIG. 3 are designated by the same reference numerals. This embodiment is an example applied to coating a photosensitive material on a cylindrical substrate when manufacturing a photosensitive drum of an electrophotographic apparatus.

In FIGS. 1 and 2, reference numeral 2 is a coating tank, and the coating tank is composed of a plurality of partition walls (6 in FIG.
It is divided into the coating chamber 2a. Each of the coating chambers 2a is provided with an inclined plate 4 on the upper part thereof, 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. Reference numeral 10-1 is a pipe for supplying the paint from the paint tank into the lower portion of the coating tank 2, and a pump 12 is attached 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 attached in the middle of these pipes, respectively. The pipe 10-2 is branched into three pipes 10-
4, 10-5 and 10-6, and flow control valves 14-3, 14-4, 1 are provided in the middle of these pipes, respectively.
4-5 are attached. And the pipes 10-4, 1
0-5 and 10-6 are connected in the lower part of the separate coating chamber 2a. Although not shown, the pipe 10-3
Is also branched in the same manner as the pipe 10-2 and is connected to a separate coating chamber via a control valve. As shown in FIG. 2, a means for rectifying the inflow paint is attached to the lower portion inside each coating chamber 2a. The rectifying means is a baffle plate 11-1.
And a perforated plate 11-2.

On the other hand, a paint outlet 16 is formed through the wall of the coating tank 2 at the lowest position of the inclined plate 4 attached to each coating chamber. A pipe 1 for returning the overflow paint to the paint tank 8 is provided at each outlet.
8-1, 18-2, 18-3, 18-4, 18-5, 1
8-6 are connected. The pipes 18-1, 18-
2, 18-3 are joined to form a pipe 18-7, and similarly, the pipes 18-4, 18-5 and 18-6 are joined to form a pipe 1-7.
8-8, and these pipes 18-7 and 18-8 are both connected to the paint tank 8.

Reference numeral 20 denotes a cylindrical substrate, which is made of aluminum, for example. Reference numeral 22 denotes a holding body for holding the bases together in a predetermined posture, and the holding body can be moved in the vertical direction by an elevating means (not shown). The base body 20 is arranged facing up and down corresponding to the arrangement of the coating chamber 2a.

Next, the operation of this embodiment will be described.

First, the control valve attached to each paint supply side pipe is opened to an appropriate opening, and the paint tank 8 is opened by the pump 12.
The paint inside is supplied into the lower part of each coating chamber 2a, and it is made to overflow from the overflow wall 6 to the surroundings evenly, and the overflow paint is collected in the paint tank 8 by the paint collecting side pipe.

Next, the substrate holder 22 is moved downward by an elevating means (not shown), and each substrate 20 is immersed in the coating material in the coating chamber 2a. FIG. 2 shows this state, and the arrows show the flow of paint.

As described above, after holding in the state shown in FIG. 2 for a predetermined time, the holding body 22 is moved upward at a predetermined speed by an elevating means (not shown), whereby the surface of the coating material is coated. The coated substrate 20 is pulled up from the coating chamber 2a.

In the above embodiment, each coating chamber 2a
The paint that has flowed into the inside is made to have a substantially uniform flow by the rectifying means and flows upward, and furthermore, the surroundings are evenly overflowed from the overflow wall 6 having substantially the same height, so that all of the surface of the immersed substrate 20 is covered. The coating material flows at a flow velocity substantially uniform with respect to the position, and thus a coating layer having extremely uniform thickness is formed on the surface of the substrate. And such a good coating is similarly realized in all coating chambers 2a,
Therefore, a coating film having a uniform film thickness is formed on all substrates.

Next, a comparison will be made between the case of applying the coating material using the apparatus of the above-mentioned embodiment and the case of applying the coating material using the conventional apparatus of FIG.

As the paint to be applied, hydrazone dye 1
A paint (viscosity 170 cps) consisting of 0 part, 10 parts of polymethylmethacrylate and 70 parts of monochlorobenzene was used. A cylindrical body made of aluminum (diameter 100 mm, length 300 mm) was used as the substrate. The coating speed (pulling speed) was 100 mm / min, and the coating was simultaneously performed on the six substrates.

After coating the coating material, the coating material was dried and the film thickness of the coating film was measured. The measurement results are shown in Table 1. The results show the average film thickness of each sample.

[0031]

[Table 1] From the above results, when the conventional apparatus was used, the variation in the coating film between the samples was 1.4 μm, whereas in the case of the example of the present invention, the variation in the coating film between the samples was 0. It is 3 μm, and it can be seen that sufficiently good coating can be applied.

In the above embodiment, an example in which six coating chambers are arranged in the coating tank is shown, but in the present invention, the number of coating chambers is not particularly limited as long as it is plural.

[0033]

As described above, according to the present invention, it is possible to simultaneously apply a coating material to a plurality of substrates with sufficient uniformity, and thus it is possible to simultaneously manufacture a plurality of electrophotographic photoreceptors having good characteristics. it can.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a coating apparatus used for carrying out the method of the present invention.

2 is a cross-sectional view taken along the line II-II of the coating apparatus of FIG. 1 in use.

FIG. 3 is a schematic perspective view showing a conventional coating device.

[Explanation of symbols]

 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 22: substrate holder

Claims (3)

[Claims] 1. A method for producing a plurality of electrophotographic photosensitive drums by applying a layer containing a photosensitive material on a surface of a cylindrical substrate by dip coating, wherein a plurality of paint tanks containing a coating material containing the photosensitive material are used. The coating material is independently supplied to the coating chambers, one of the substrates is placed in each coating chamber and immersed in the coating chamber, and the coating material overflowed from each coating chamber is collected in the coating tank. A method of manufacturing an electrophotographic photosensitive member by dip coating, which comprises: 2. The method for producing an electrophotographic photosensitive member by immersion coating according to claim 1, wherein the coating material is rectified in each coating chamber. 3. The method of manufacturing an electrophotographic photosensitive member by immersion coating according to claim 2, wherein the rectification of the coating material is performed on the coating material supplied from the coating material tank to each coating chamber.