JPS62193668A - Drum coating device - Google Patents

Abstract

PURPOSE:To prevent the pulsation of a coating liquid surface and to uniformly apply a coating liquid on a drum by raising the drum together with the coating liquid in a guide pipe and allowing the coating liquid to overflow from the top end face of the guide pipe according to such rise. CONSTITUTION:A drum receiving base 30 ascends in the light tight state with the guide pipe 20 to allow the coating liquid in the guide pipe 20 to overflow from the top end of the guide pipe 20 to a coating liquid tank 10 and the coating liquid in the coating liquid tank 10 flows into the lower side of the drum receiving base 30 in the guide pipe 20 when a lifting rod 40 of a device for applying the coating liquid such as photosensitive material on the outside peripheral face of the cylindrical drum such as electrophotographic sensitive body is raised. The liquid level falls according to the rise of the drum receiving base 30. The coating liquid in the guide pipe 20 overflows and the coating liquid level maintains the approximately equal and specified level when the liquid level falls down to the level lower than the top end of the guide pipe 20 according to the rise of the drum receiving base 30. The coating liquid is thus applied to a specified film thickness on the outside circumference of the drum.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. H-tongue (Industrial Application Field) The present invention is based on the following features: 1. For example, a coating liquid such as a photosensitive substance is applied to the outer peripheral surface of a cylindrical drum such as an electrophotographic photoreceptor. The present invention relates to a coating device.

(Prior Art) For example, when manufacturing an electrophotographic photoreceptor by applying a coating liquid containing a photosensitive substance to a cylindrical drum, the coating liquid is applied to the drum surface to a uniform thickness. This is very important. As a method for manufacturing an electrophotographic photoreceptor,
A common method is a dipping method in which a cylindrical drum is immersed in a coating liquid and the drum is pulled up from the coating liquid in the axial direction to the outside to apply the coating liquid to the outer peripheral surface of the drum.

In the immersion method, when the drum is lifted from the coating solution, the volume of the drum is ejected from the solution.

The liquid level will drop. For this reason, the drawing speed of the drum relative to the level of the second coating liquid changes, and the coating liquid cannot be applied to the drum in a uniform film thickness. In order to keep the coating liquid level at a constant level at all times, when the drum is lifted from the coating liquid, new coating liquid must be supplied to the coating liquid tank at a rate that corresponds to the rate at which the liquid level is falling. . If the coating liquid is supplied into the coating liquid tank using, for example, a pump, the liquid level will pulsate, making it difficult to apply the coating liquid to a uniform film thickness. In order to keep the liquid level constant, the amount of coating liquid supplied to the coating liquid tank must be set in accordance with the drum diameter, drum pulling speed, etc.3. Highly precise equipment such as flow control devices is required.

On the other hand, a cylindrical pedestal having the same outer diameter as the drum is disposed on the bottom of the coating liquid tank so that it can be raised and lowered while maintaining a liquid-tight state with the bottom. A method has been considered in which the drum is immersed in the coating liquid by lowering and raising the pedestal with the drum placed thereon, and the drum is then pulled out from the coating liquid. According to this method, even if the drum immersed in the coating liquid is lifted out of the coating liquid by the lifting of the nine pedestals, the pedestal with an outer diameter equal to the outer diameter of the drum will enter the coating liquid from the bottom of the coating liquid tank. However, the sum of the volumes of the drum and the pedestal within the coating liquid does not change, and therefore the liquid level of the coating liquid remains at a constant level.

However, in this method, when the coating liquid is applied to a drum having an outer diameter different from the outer diameter of the two pedestals.

As described above, the coating liquid level changes up and down. Therefore.

If the drum diameter is changed, it is necessary to replace the pedestal 5 with one having an outer diameter equal to the outer diameter of the drum to which the coating liquid is applied. However, since the two pedestals must be arranged so that they can be moved up and down while maintaining a liquid-tight state with respect to the coating liquid tank, it is not easy to replace the nine pedestals. Furthermore, even if one pedestal is made to have the same diameter as the drum, pulsations in the liquid level when the drum leaves the coating liquid cannot be prevented.

(Problems to be Solved by the Invention) The present invention solves the conventional problems described in "-".
The purpose is to provide a drum coating device that can prevent pulsations in the liquid level of the coating liquid and keep the level constant at all times when a drum immersed in the coating liquid is pulled up from the coating liquid. . Another object of the present invention is to easily prevent pulsation of the liquid level of the coating liquid without requiring any special operation or equipment, even if the outer diameter of the drum to which the coating is applied is changed, and to maintain that level at all times. An object of the present invention is to provide a drum coating device that can be maintained constant.

(Means for Solving the Problems) The drum coating device of the present invention includes a coating liquid tank that stores a coating liquid, and a coating liquid tank that is fitted inside the coating liquid tank and whose upper end surface is located below the upper end surface of the coating liquid tank. A cylindrical guide tube located at the bottom of which communicates with the inside of the coating liquid tank, and a drum to which the coating liquid is applied are placed inside the guide tube, and the coating liquid that has flowed into the guide tube is placed in the guide tube. and a drum holder fitted in the acid guide tube in a liquid-tight manner and movable up and down, in order to raise and lower the drum.

an elevator rod having a cross-sectional area smaller than the cross-sectional area of the drum, whose upper end surface is attached to the drum pedestal, and which is disposed in the coating liquid tank in a liquid-tight manner and movable up and down; and the coating liquid. a coating liquid supply device that supplies the coating liquid to the tank, and the amount of coating liquid supplied by the coating liquid supply device is equal to the amount of coating liquid entering from the lower end of the guide tube due to the second rise of the drum holder. is set to be smaller than the difference in the amount of coating liquid overflowing from the upper end of the guide tube to the coating liquid tank, thereby achieving the above object.

(Example) Examples of the present invention will be described below.

As shown in FIGS. 1 and 2, the drum coating device of the present invention includes a coating liquid tank 1o, a guide tube 20 fitted in the coating liquid tank 1o, and a slider on the inner circumferential surface of the guide tube 2o. A moving drum pedestal 30 and a lifting rod 4 that raises and lowers the drum pedestal 3o.
0.

The coating liquid tank 1 and 9 in which the coating liquid is stored have a cylindrical shape, for example. The upper part of the coating liquid tank 1o constitutes a small diameter part 11 having a smaller cross-sectional area than the lower main body. Excess amount of coating liquid is discharged beyond this small diameter portion 11 into an overflow coating liquid tank (not shown). At the bottom of the coating liquid tank 10, there is a coating liquid supply device (for example,
pump) 14 is connected.

The guide tube 20 has a cylindrical shape, and is provided with four support rods 21.21° so as to be concentric with the coating liquid tank 10.
It is supported within the coating liquid tank 10 by. The upper end surface of the guide tube 20 is located slightly below the upper end surface of the small diameter portion 11 in the coating liquid tank 10. The lower end surface of the guide tube 20 has a predetermined distance from the bottom surface 12 of the coating liquid tank 10, and as a result, the inside of the guide tube 20 and the inside of the coating liquid tank 10 are in communication.

A drum holder 30 is fitted inside the guide tube 20 . The drum pedestal 30 has a blade 31 that slides into liquid-tight contact with the inner peripheral surface of the guide tube 20. therefore.

The drum pedestal 30 can move up and down along the inner peripheral surface of the guide tube 30 while maintaining a liquid-tight state. On the drum pedestal 30,
A drum 50 to which a coating liquid is to be applied is placed with its axis facing vertically. The lower end surface of the drum 50 and the drum pedestal 30 are fitted in a liquid-tight manner.

A cap 51 is fitted to the upper end of the drum 50 in a liquid-tight manner.

The lower surface of the drum pedestal 30 is attached to the upper end surface of the lifting rod 40. The lifting rod 40 is a cylinder having a cross-sectional area smaller than that of the drum 50 placed on the drum pedestal 30. The lifting rod 40 penetrates the bottom surface 12 of the coating liquid 10 through the blade 13 in a liquid-tight manner, and as a result, the lifting rod 40 maintains a liquid-tight state with respect to the bottom surface 12 of the coating liquid tank 10. It can be raised and lowered.

When the drum pedestal 30 rises within the guide tube 20 due to the rise of the lifting rod 40, the drum pedestal 30 moves up into the guide tube 2.
0 slides in a liquid-tight manner, so the coating liquid in the guide tube 20 overflows into the coating liquid tank 10 from the upper end surface of the guide tube 20, and the coating liquid in the coating liquid tank 10 flows from the lower end surface of the guide tube 20. The coating liquid inside flows in. At this time, since the cross-sectional area of the drum 50 on the drum pedestal 30 is larger than the cross-sectional area of the lifting rod 40, the amount of coating liquid overflowing from the upper end surface of the guide tube 20 is transferred from the lower end surface of the guide tube 20 to the guide tube 20.
less than the amount of coating liquid flowing into the interior. The pump 14 that supplies the coating liquid into the coating liquid tank 10 supplies an amount of coating liquid that is smaller than the difference between the amount of coating liquid flowing into the guide tube 20 and the amount of coating liquid that overflows when the drum pedestal 30 is raised. It is set to get.

(Function) As shown in FIG. 3, the device of the present invention having such a configuration has
A drum 50 to which a coating liquid is to be applied is placed on the drum pedestal 30 in a liquid-tight manner. A cap 51 is fitted onto the upper end surface of the drum 50 to prevent the coating liquid from entering the drum 50. Next.

The lifting rod 40 is lowered, and the upper end surface of the drum 50 is brought to a coating start position that is the same as or slightly below the upper end surface of the small diameter portion 11 of the coating liquid tank 10. The coating liquid is constantly supplied by the pump 14 at the time of starting coating.

The coating liquid level of the coating liquid tank 10 is higher than the upper end surface of the coating liquid tank 10, and the coating liquid overflows and is discharged to the overflow coating liquid tank.

In this state, the lifting rod 40 is raised and the drum pedestal 3
0 is raised in a liquid-tight state with the guide tube 20.

As the drum holder 30 rises, the coating liquid in the guide tube 20 overflows from the upper end of the guide tube 20 to the coating liquid tank 10 . of coating liquid flows in.

As the drum pedestal 30 rises, the liquid level in the coating liquid tank 10 decreases. Then, when the liquid level falls below the upper end surface of the guide tube 20, the coating liquid in the guide tube 20 overflows, and the coating liquid level in the guide tube 20 decreases.

A constant level approximately equal to the upper end surface of the guide tube 20 is always maintained. Then, the coating liquid is applied to the outer circumferential surface of the drum, which has exited from the coating liquid level in the guide tube 20 to the outside, with a constant film thickness.

At this time, in order to speed up the drop of the coating liquid level from the upper end surface of the coating liquid tank 10 to the upper end surface of the guide tube 20 immediately after the start of coating, a small diameter is used to reduce the cross-sectional area of the upper part of the coating liquid tank 10. 11 is provided, so that the coating liquid level can be quickly lowered, and changes in the pulling speed on the drum 50 can be reduced.

When the entire drum 50 is completely retracted from the upper end of the guide tube 20 to the outside, the coating work on the drum 50 is completed, the drum 50 is removed from the drum holder 30, and a new coating liquid is applied to the outer peripheral surface of the drum 50. The drum to be coated is placed on a drum pedestal 30. In this condition.

The drum pedestal 30 is lowered. As the drum coating device descends, the coating liquid below the drum holder 30 flows out from the lower part of the guide tube 20 into the coating liquid tank 10, as shown in FIG. 4, and the coating liquid is supplied by the pump 14. As a result, the coating liquid level in the coating liquid tank 10 rises. Then, when the coating liquid level rises above the upper end surface of the guide tube 20, the coating liquid in the coating liquid tank 10 flows into the guide tube 20 by overflowing over the upper end surface of the guide tube 20. When the upper end surface of the drum 50 reaches the coating start position at the same position as or slightly below the upper end surface of the coating liquid tank 10, the lowering of the drum pedestal 30 is stopped. On the other hand, the coating liquid tank 10 by the pump 14
The supply of the coating liquid to the coating liquid tank 10 continues, and the coating liquid overflows from the upper end surface of the coating liquid tank 10. In this state, the drum pedestal 30 is raised and the above-described steps are repeated to coat the outer peripheral surface of the drum 50 with the coating liquid in a uniform film thickness.

As the drum pedestal 30 rises, the amount of coating liquid flowing out from the upper end of the guide tube 20 is set to Vl m/min, and the guide tube 20
The amount of coating liquid flowing into the guide tube 20 from the lower end of
/min, and the amount of coating liquid supplied into the coating liquid tank 10 by the pump 14 is V,%/min. Since the cross-sectional area of the drum 50 is larger than the cross-sectional area of the lifting rod 40, V2>V.
, becomes. Further, the amount vp of the coating liquid supplied by the pump 14 is ν
2<V2-V. If the amount of coating liquid supplied by the pump 14 vp becomes ν2≧Vz Vl, the coating liquid always overflows the coating liquid tank 10 and is discharged into the overflow coating liquid tank regardless of whether the drum pedestal 30 is raised or lowered. Therefore, the liquid level in the coating liquid tank 10 does not change.

It is not possible to maintain the coating liquid level at the upper end of the guide tube 11 during coating. Therefore, if v≧VZ-V, uniform application will not be possible due to pump pulsation.

(Effects of the Invention) As described above, the coating device of the present invention allows the drum to rise together with the coating liquid in the guide tube, and as it rises, the coating liquid overflows from the upper end surface of the guide tube into the coating liquid tank. Therefore, pulsation of the coating liquid surface is prevented, and the coating liquid is applied to the drum with a uniform film thickness. The coating liquid tank is constantly supplied with coating liquid so that it can overflow from the upper end surface of the guide tube during the coating process, so the coating liquid level can be quickly detected without using any equipment to detect the coating liquid level. is raised. Even if the drum diameter is changed, as long as the drum diameter is larger than the lifting rod, the coating liquid can be applied with a uniform film thickness without any problems, as described above. Further, the drum can be reliably coated with a small amount of coating liquid. Furthermore, since the coating liquid moves, the coating liquid is stirred, and it becomes possible to uniformly apply the coating liquid without using a special stirring device.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the coating device of the present invention. FIG. 2 is a sectional view taken along line 11-4 in FIG. 1, and FIGS. 3 and 4 are explanatory diagrams of the operation of the apparatus of the present invention, respectively. 10... Coating liquid tank, 20... Guide tube, 30...
Drum pedestal. 40... Lifting rod, 50... Drum. Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A coating liquid tank that contains a coating liquid, and a coating liquid that is fitted into the coating liquid tank, and whose upper end surface is located below the upper end surface of the coating liquid tank, and whose lower part contains the coating liquid. A cylindrical guide tube that communicates with the inside of the tank, and a drum to which a coating liquid is applied are placed in the guide tube, and the guide is configured to move up and down the drum together with the coating liquid that has flowed into the guide tube. a drum pedestal fitted into the tube in a liquid-tight manner and movable up and down, the cross-sectional area of which is smaller than the cross-sectional area of the drum; a lifting rod arranged to be liquid-tight and movable up and down; and a coating liquid supply device for supplying the coating liquid to the coating liquid tank, wherein the amount of the coating liquid supplied by the coating liquid supply device is controlled by the amount of the coating liquid supplied to the drum. As the pedestal rises, the amount of coating liquid that enters from the lower end of the guide tube,
The drum coating device is set to be smaller than the difference in the amount of coating liquid that overflows from the upper end of the guide tube to the coating liquid tank.