JP7803183B2 - Coating device, coating method, and photoreceptor manufacturing method - Google Patents

Description

The present invention relates to a coating device, a coating method, and a method for manufacturing a photoreceptor.

Patent Document 1 below discloses a coating device that has a coating liquid supply mechanism and a coating liquid holding member with a circular opening. A cylindrical body is inserted into the opening and the cylindrical body is moved vertically downward relative to the coating liquid holding member to apply coating liquid to the outer peripheral surface of the cylindrical body. The coating liquid holding member is held so that it can move radially around the cylindrical body, and the circular opening is formed as a coating liquid scraper.

Japanese Patent Application Publication No. 10-080656

The objective of the present disclosure is to provide a coating device, a coating method, and a method for manufacturing a photoreceptor that suppress the occurrence of foreign matter defects in the coating film on the outer surface of a cylinder compared to when the relative speed of the coating liquid flowing down the outer surface of a cylinder is less than 10 mm/s, and that suppress the occurrence of coating unevenness in the coating film on the outer surface of a cylinder compared to when the relative speed of the coating liquid flowing down the outer surface of a cylinder is greater than 200 mm/s.

The coating device according to the first aspect comprises a coating liquid holding unit that has an upper opening and a lower opening, and that holds a coating liquid. The coating liquid is applied to the outer peripheral surface of a cylinder by passing a cylinder through the upper opening and the lower opening and moving the cylinder relatively upward in the vertical direction; a supply unit that supplies the coating liquid to the coating liquid holding unit; and a movement unit that moves the cylinder relatively in the vertical direction with respect to the coating liquid holding unit. The supply amount and movement speed of the supply unit and the movement unit are set so that the relative velocity V of the coating liquid flowing down the outer peripheral surface of the cylinder when the cylinder is moved relatively upward in the vertical direction is 10 mm/s or more and 200 mm/s or less.

The coating device according to the second aspect is the coating device according to the first aspect, wherein the supply amount and movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved relatively upward in the vertical direction, the relative velocity V of the coating liquid flowing down the outer peripheral surface of the cylindrical body is 80 mm/s or more and 130 mm/s or less.

The coating device according to the third aspect is the coating device according to the second aspect, wherein the supply amount and movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved relatively upward in the vertical direction, the relative velocity V of the coating liquid flowing down the outer peripheral surface of the cylindrical body is 100 mm/s or more and 110 mm/s or less.

The coating device according to a fourth aspect is the coating device according to any one of the first to third aspects, wherein the moving unit moves the cylinder vertically downward relative to the coating liquid holding unit, and then moves the cylinder vertically upward relative to the coating liquid holding unit; the supply amount and moving speed of the supply unit and the moving unit are set so that when the cylinder is moved vertically downward relative to the coating liquid, the relative speed V of the coating liquid flowing down the outer surface of the cylinder is 10 mm/s or more and 200 mm/s or less.

The coating device according to the fifth aspect is the coating device according to any one of the first to fourth aspects, wherein the moving unit moves the cylindrical body in the vertical direction without changing the vertical position of the coating liquid holding unit.

The coating device according to the sixth aspect is the coating device according to any one of the first to fifth aspects, wherein the coating liquid holding unit has an annular body inside which the cylindrical body penetrates, and into which the coating liquid held in the coating liquid holding unit flows in from above and out from below as the annular body moves relative to the cylindrical body, and the annular body is installed so as to be displaceable relative to the coating liquid holding unit along an installation surface that intersects with the direction of the relative movement.

The coating method according to the seventh aspect is a coating method for coating a coating liquid using the coating device according to any one of the first to sixth aspects, and includes a supply step of passing the lower part of the cylinder through the upper opening and the lower opening of the coating liquid holding part and supplying the coating liquid from the supply part to the coating liquid holding part; a first movement step of moving the cylinder downward in the vertical direction relative to the coating liquid holding part and positioning the upper part of the cylinder opposite the coating liquid holding part; and a second movement step of moving the cylinder upward in the vertical direction relative to the coating liquid holding part and setting the relative speed V of the coating liquid at which the coating liquid flows down the outer peripheral surface of the cylinder to between 10 mm/s and 200 mm/s, and coating the coating liquid on the outer peripheral surface of the cylinder.

The coating method according to the eighth aspect is the coating method according to the seventh aspect, wherein in the first movement step, the relative velocity V of the coating liquid flowing down the outer peripheral surface of the cylindrical body is set to 10 mm/s or more and 200 mm/s or less.

The coating method according to the ninth aspect is the coating method according to the seventh or eighth aspect, wherein the cylindrical body is a cylindrical member or a cylindrical core material with an endless belt-like member wrapped around it.

The photoreceptor manufacturing method according to the tenth aspect is a photoreceptor manufacturing method that uses the coating method according to any one of the seventh to ninth aspects, wherein the cylindrical body is a metallic cylindrical member or a cylindrical core material with a metallic endless belt-like member wound around it, and the coating liquid is a photosensitive material.

With the coating device of the first aspect, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 200 mm/s.

With the coating device of the second aspect, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 80 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 130 mm/s.

With the coating device of the third aspect, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is less than 100 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is greater than 110 mm/s.

With the coating device of the fourth aspect, when the cylinder is moved downward in the vertical direction relative to the cylinder, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is greater than 200 mm/s.

The coating device according to the fifth aspect has a simpler structure than a configuration in which the coating liquid holding unit moves up and down without changing the vertical position of the cylindrical body.

With the coating device according to the sixth aspect, unevenness in the thickness of the coating film on the outer surface of the cylindrical body is reduced compared to when the annular body is fixed to the installation surface.

According to the coating method of the seventh aspect, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is greater than 200 mm/s.

According to the coating method of the eighth aspect, in the first moving step, the occurrence of foreign matter defects in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film on the outer surface of the cylinder is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 200 mm/s.

The coating method according to the ninth aspect reduces the occurrence of foreign matter defects in the coating film on the outer surface of a cylindrical member or an endless belt-like member when applying a coating liquid to the outer surface of the cylindrical member or the endless belt-like member, and reduces the occurrence of coating unevenness in the coating film on the outer surface of the cylindrical member or the endless belt-like member.

According to the photoreceptor manufacturing method of the tenth aspect, when applying a coating liquid to the outer peripheral surface of the photoreceptor, the occurrence of foreign matter defects in the coating film on the outer peripheral surface of the photoreceptor is suppressed, and the occurrence of coating unevenness in the coating film on the outer peripheral surface of the photoreceptor is suppressed.

1 is a cross-sectional view showing an outline of the overall configuration of a coating apparatus according to a first embodiment. 3 is a cross-sectional view showing an enlarged view of a part of a coating liquid holding unit used in the coating device according to the first embodiment. FIG. 4 is a cross-sectional view showing the flow of coating liquid when the coating liquid is applied to a cylindrical body from a coating liquid holding unit used in the coating device according to the first embodiment. FIG. 1A is a perspective view showing an annular body used in the coating device according to the first embodiment, and FIG. 1B is a perspective view showing the annular body in a partially cut-away state. (A) is a schematic diagram showing the state before a cylindrical body is inserted into the coating liquid holding section of the coating device in the first embodiment, (B) is a schematic diagram showing the state after the cylindrical body has been inserted into the coating liquid holding section of the coating device and lowered, and (C) is a schematic diagram showing the state in the middle of moving the cylindrical body upward in the vertical direction relative to the coating liquid holding section. 5A is a side view showing a part of a cylindrical body on whose outer surface a coating film made of a coating liquid is formed, and FIG. 5B is a cross-sectional view taken along line 5B-5B in FIG. 5A. FIG. 10 is a cross-sectional view showing a configuration in the vicinity of a ring-shaped body used in a coating device according to a second embodiment. FIG. 10 is a perspective view showing a partially cutaway view of an annular body used in a coating device according to a second embodiment.

The following describes embodiments of the technology disclosed herein. In the following description, the direction indicated by the arrow UP in the drawings refers to the upward direction of the device.

First Embodiment
<Overall configuration of coating device>
FIG. 1 shows a cross-sectional view of an example of a coating apparatus 10 according to the first embodiment.

As shown in FIG. 1, the coating device 10 is an apparatus that coats the outer peripheral surface 100A of a cylindrical body 100 with a coating liquid L. The coating device 10 includes a coating liquid holding unit 12 that holds the coating liquid L, and an annular body 32 disposed inside the coating liquid holding unit 12. The coating device 10 also includes a container 14 that contains the coating liquid L that has flowed down from the coating liquid holding unit 12, and a circulation unit 16 that circulates the coating liquid L from the container 14 to the coating liquid holding unit 12. The circulation unit 16 is an example of a supply unit that supplies the coating liquid L to the coating liquid holding unit 12. The coating device 10 also includes a cylindrical housing 20 that supports the coating liquid holding unit 12. The coating device 10 also includes a moving unit 80 that moves the cylindrical body 100 up and down relative to the coating liquid holding unit 12. The moving unit 80 is an example of a moving unit.

(Cylindrical body)
The cylindrical body 100 is, for example, a metallic cylindrical member, or a cylindrical core material with a metallic endless belt-like member wound around it. The cylindrical member or endless belt-like member constituting the cylindrical body 100 is, for example, a photoreceptor substrate for electrophotography. Furthermore, for example, when a photoreceptor substrate for electrophotography is used as the cylindrical body 100, a liquid containing a photosensitive material is used as the coating liquid L. In this embodiment, the coating device 10 applies the coating liquid L to the cylindrical member or endless belt-like member constituting the cylindrical body 100. By using a liquid containing a photosensitive material as the coating liquid L, a photoreceptor for electrophotography can be manufactured.

(Housing)
1, the housing 20 is made of a cylindrical member and is arranged so that the axial direction of the housing 20 is the vertical direction. As an example, the housing 20 includes a cylindrical portion 20A arranged along the vertical direction.

The upper end of the cylindrical portion 20A is provided with an upper wall portion 21B extending radially inward, and a circular opening 21C is formed in the upper wall portion 21B. The inner diameter of the opening 21C is larger than the outer diameter of the cylindrical body 100. The cylindrical body 100 is configured to pass through the opening 21C in the axial direction.

(Coating liquid holding section)
1 and 2, the coating liquid holding unit 12 has a function of holding the coating liquid L supplied from the circulation unit 16. The coating liquid holding unit 12 includes a case 24. The case 24 includes a cylindrical portion 24A, an upper wall portion 24B bent radially inward from the upper end of the cylindrical portion 24A, and a block portion 24C provided on the lower side of the cylindrical portion 24A.

An inlet 24E through which the coating liquid L flows is provided at the bottom of one radial side (the right side in Figure 1) of the cylindrical portion 24A.

A circular upper opening 25 is provided in the upper wall portion 24B (see Figure 2). The inner diameter of the upper opening 25 is larger than the outer diameter of the cylindrical body 100. The upper opening 25 of the upper wall portion 24B is configured so that the cylindrical body 100 passes through it in the axial direction.

The block portion 24C includes a bottom wall portion 26A that connects to the lower end of the cylindrical portion 24A, and a cylindrical inner wall portion 26B that extends upward from the radially inner end of the bottom wall portion 26A (see Figure 1). An inclined portion 27 is formed on the upper side of the inner wall portion 26B, sloping upward radially inward. A circular lower opening 28 is provided at the upper end of the inclined portion 27 of the inner wall portion 26B. The inner diameter of the lower opening 28 is larger than the outer diameter of the cylindrical body 100. The inner diameter of the lower opening 28 is also smaller than the inner diameter of the upper opening 25. The cylindrical body 100 is configured to pass axially through the lower opening 28 of the block portion 24C.

The application liquid holding unit 12 is supported on the upper side of the interior of the housing 20 by a support unit (not shown).

The case 24 comprises a cylindrical portion 24A, an upper wall portion 24B, and a block portion 24C, with the upper side of the block portion 24C opening radially inward. The upper portion of the block portion 24C is provided with an installation surface 30 on which the annular body 32 is disposed so as to be relatively movable. The installation surface 30 functions to support the annular body 32 so as to be relatively movable. The installation surface 30 is flat and disposed horizontally.

Flow paths 34 through which the coating liquid L flows are provided inside the case 24 between the cylindrical portion 24A and the block portion 24C, and between the cylindrical portion 24A and the annular body 32. The upstream end of the flow path 34 in the direction of flow of the coating liquid L is connected to the inlet 24E (see Figure 1).

A cylindrical body 100 passes through the upper opening 25 and the lower opening 28 of the coating liquid holding unit 12, and the cylindrical body 100 moves vertically relative to the coating liquid holding unit 12 by the moving device 80 (see Figure 5). The installation surface 30 is positioned in a direction that intersects with the direction of relative movement of the cylindrical body 100.

(Mobile device)
The moving device 80 has a function of moving the cylindrical body 100 in the vertical direction relative to the coating liquid holding unit 12. In the first embodiment, the moving device 80 moves the cylindrical body 100 in the vertical direction without changing the vertical position of the coating liquid holding unit 12. The moving device 80 is configured, for example, with a rack and pinion, an actuator, or a hydraulic cylinder. As an example, the moving device 80 is configured with a hydraulic cylinder and includes a main body 82 and a rod 84 that extends downward from the main body 82 and is movable forward and backward. A gripping portion 86 that grips the cylindrical body 100 from the inner circumferential surface side is provided at the tip of the rod 84. The gripping portion 86 has multiple gripping surfaces (not shown) that expand or contract in the radial direction, and grips the cylindrical body 100 from the inner circumferential surface side by expanding the diameter of the multiple gripping surfaces in the radial direction.

In the moving device 80, the rod 84 moves back and forth relative to the main body 82, causing the cylindrical body 100 to move up and down relative to the application liquid holding unit 12. The up and down movement of the cylindrical body 100 by the moving device 80 will be described later.

(cyclic body)
1 and 2, the annular body 32 is provided in an open portion on the radially inner side of the case 24. The annular body 32 is disposed above the mounting surface 30 on the upper part of the block portion 24C within the case 24. The annular body 32 is disposed along the mounting surface 30 on the upper part of the block portion 24C so as to be relatively displaceable.

The inner diameter of the annular body 32 is larger than the outer diameter of the cylindrical body 100. The cylindrical body 100 is configured to pass through the interior of the annular body 32 in the axial direction. That is, the cylindrical body 100 passes through the interior of the annular body 32, penetrating the upper opening 25 and lower opening 28 of the coating liquid holding section 12. As an example, the inner diameter of the annular body 32 is smaller than the inner diameter of the lower opening 28. The inner surface 32A of the annular body 32 is exposed in the area where the cylindrical body 100 passes through (see Figure 2).

As an example, the annular body 32 is placed on the installation surface 30 above the block portion 24C with the application liquid L interposed therebetween. The annular body 32 is movable (slidable in this embodiment) relative to the installation surface 30 with the application liquid L interposed therebetween. In this embodiment, no drive unit is provided to directly drive the annular body 32, and the annular body 32 autonomously slides relative to the installation surface 30.

2 and 3, a slit-shaped discharge portion 36 is provided circumferentially between the upper opening 25 of the upper wall portion 24B of the coating liquid holding portion 12 and the annular body 32. The coating liquid L is discharged from the discharge portion 36 (see FIG. 3). That is, the discharge portion 36 faces the area of the coating liquid holding portion 12 through which the cylindrical body 100 passes, and the coating liquid L is discharged toward the cylindrical body 100. As shown in FIG. 3, the coating liquid L discharged from the discharge portion 36 flows from the upper opening 25 to the upper surface of the upper wall portion 24B and overflows, as indicated by arrow C, and also flows downward between the annular body 32 and the outer peripheral surface 100A of the cylindrical body 100, as indicated by arrow D. That is, the annular body 32 is configured so that the coating liquid L held in the coating liquid holding portion 12 flows in from above and flows out from below as the annular body 32 moves relative to the cylindrical body 100.

As shown in Figures 3 and 4, the inner peripheral surface 32A of the annular body 32 is provided with an inclined surface 33A located on the upper side and sloping downward from the upper opening 25 side, and a straight portion 33B extending vertically from the lower end of the inclined surface 33A (see Figure 2).

In the coating device 10, the cylindrical body 100 is moved upward in the vertical direction relative to the coating liquid holding unit 12, thereby coating the outer peripheral surface 100A of the cylindrical body 100 with the coating liquid L (see FIGS. 5(B) and 5(C)). In the coating liquid holding unit 12, the coating liquid L flows between the outer peripheral surface 100A of the cylindrical body 100 and the inner peripheral surface 32A of the annular body 32, and the pressure of the flowing coating liquid L displaces the annular body 32 relative to the installation surface 30. At this time, the annular body 32 is displaced relative to the installation surface 30 so that the gap between the outer peripheral surface 100A of the cylindrical body 100 and the inner peripheral surface 32A of the annular body 32 is uniform along the circumferential direction.

Figure 5 shows an example of a method for applying coating liquid L to the outer peripheral surface 100A of a cylindrical body 100 using the coating liquid holding unit 12 of the coating device 10. In Figure 5, the moving device 80 is not shown to make it easier to understand the moving position of the cylindrical body 100 and the applied state of the coating liquid L.

As shown in FIG. 5(A), the moving device 80 (see FIG. 1) inserts the cylindrical body 100 axially from above the coating liquid holding unit 12. With the lower end of the cylindrical body 100 inserted into the coating liquid holding unit 12, the circulation unit 16 (see FIG. 1) supplies the coating liquid L to the coating liquid holding unit 12, thereby filling the gap between the annular body 32 of the coating liquid holding unit 12 and the outer peripheral surface 100A of the cylindrical body 100 with the coating liquid L (supply step). Then, while the circulation unit 16 (see FIG. 1) supplies the coating liquid L to the coating liquid holding unit 12, the moving device 80 (see FIG. 1) moves the cylindrical body 100 downward (in the direction of arrow A) (first movement step). At this time, the coating liquid L may be ejected from the ejection unit 36 so as to overflow from above the coating liquid holding unit 12, and the coating liquid L may also be allowed to flow downward from the lower opening 28.

As shown in Figure 5 (B), the moving device 80 (see Figure 1) further lowers the cylinder 100 in the direction of arrow A, and the circulation unit 16 (see Figure 1) supplies the coating liquid L to the coating liquid holding unit 12. Then, when the cylinder 100 reaches the bottom, the upper axial end of the cylinder 100 is positioned opposite the coating liquid holding unit 12.

Then, as shown in FIG. 5(C), the cylindrical body 100 is moved vertically downward relative to the coating liquid holding unit 12 (in the direction of arrow B) (second movement step). At this time, the coating liquid L is ejected from the ejection unit 36 so that it overflows from above the coating liquid holding unit 12. As a result, the coating liquid L flows downward from the lower opening 28 and is applied to the outer peripheral surface 100A of the cylindrical body 100 located above the upper opening 25, forming a coating film 102 on the outer peripheral surface 100A of the cylindrical body 100 (see FIG. 6(B)). The coating film 102 is an example of a coating film. Note that FIG. 5 is an example of a method for applying the coating liquid L to the outer peripheral surface 100A of the cylindrical body 100, and the application method can be changed.

As shown in Figure 6(A), during the process of applying the coating liquid L to the outer peripheral surface 100A of the cylindrical body 100, the coating liquid L applied to the outer peripheral surface 100A of the cylindrical body 100 flows downward along the outer peripheral surface 100A of the cylindrical body 100.

As shown in FIG. 1, the coating device 10 has a wall 50 below the coating liquid holding unit 12 inside the housing 20. The wall 50 has an opening 50A through which the cylinder 100 passes. The diagonally lower end of the wall 50 has a hole 50B located adjacent to the inner wall surface of the housing 20. This allows the coating liquid L to flow down from the hole 50B in the wall 50, along the inner wall surface of the housing 20, and be collected in the container 14.

(container)
1, the container 14 is provided at the bottom in the vertical direction of the housing 20. As an example, the container 14 is connected to the bottom end of the cylindrical portion 20A of the housing 20.

The container 14 comprises a cylindrical portion 14A connected to the cylindrical portion 20A, and a recess 14B located below the cylindrical portion 14A and having a valley-shaped recessed bottom. In this embodiment, the bottom of the recess 14B has an inverted cone-like recess with an inner diameter that gradually decreases downward.

The recess 14B has a bottom surface that slopes downward from the cylindrical portion 14A side toward the center in the radial direction, with the center of the recess 14B being the lowest part. The recess 14B of the container 14 is designed to collect the coating liquid L that flows down from the coating liquid holding portion 12 side. As an example, the liquid level L1 of the coating liquid L is located on the upper side of the recess 14B.

(circulation department)
1, the circulation unit 16 includes a supply pipe 60 that supplies the coating liquid L in the container 14 to the coating liquid holding unit 12, and a pump 62 provided midway along the supply pipe 60. The pump 62 transfers the coating liquid L in the supply pipe 60 from the container 14 side to the coating liquid holding unit 12 side.

The upstream end 60A of the supply pipe 60 in the flow direction of the coating liquid L is connected to the lower part of the container 14. In this embodiment, the upstream end 60A of the supply pipe 60 is connected to the center, which is the lowest part of the recess 14B. The downstream end 60B of the supply pipe 60 in the flow direction of the coating liquid L penetrates the housing 20 and is connected to the inlet 24E of the coating liquid holding unit 12. As a result, the coating liquid L flowing through the supply pipe 60 is supplied from the inlet 24E to the flow path 34. Note that the upstream side or downstream side in the flow direction of the coating liquid L may sometimes be simply referred to as the "upstream side" or "downstream side" without referring to the "flow direction of the coating liquid L."

A viscosity measuring unit 66 that measures the viscosity of the coating liquid L is provided midway along the supply pipe 60, downstream of the pump 62 in the flow direction of the coating liquid L. Furthermore, a filter 68 that removes foreign matter contained in the coating liquid L is provided midway along the supply pipe 60, upstream of the viscosity measuring unit 66 in the flow direction of the coating liquid L.

In the coating device 10, by driving the pump 62 of the circulation unit 16, the coating liquid L in the container 14 is supplied to the coating liquid holding unit 12 through the supply pipe 60. In the coating liquid holding unit 12, the coating liquid L is applied to the outer peripheral surface 100A of the cylindrical body 100, and the coating liquid L that flows down the outer peripheral surface 100A of the cylindrical body 100 is collected in the container 14. The coating liquid L in the container 14 is then supplied to the coating liquid holding unit 12 through the supply pipe 60. Therefore, the circulation unit 16 circulates the coating liquid L in the container 14 to the coating liquid holding unit 12.

(Relative velocity of coating liquid flowing down the outer surface of the cylinder)
The supply amount and movement speed of the circulation unit 16 and the movement device 80 are set so that when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement step), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is 10 mm/s or more and 200 mm/s or less. Furthermore, when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement step), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is more preferably 80 mm/s or more and 130 mm/s or less, and even more preferably 100 mm/s or more and 110 mm/s or less. As an example, when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement step), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is set to 100 mm/s.

For example, when the speed at which the moving device 80 moves the cylindrical body 100 upward in the vertical direction is constant, if the amount of coating liquid L supplied to the coating liquid holding unit 12 by the circulation unit 16 increases, the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 increases. Also, when the amount of coating liquid L supplied to the coating liquid holding unit 12 by the circulation unit 16 is constant, if the speed at which the moving device 80 moves the cylindrical body 100 upward in the vertical direction decreases, the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 increases.

As an example, the supply rate of the coating liquid L supplied by the circulation unit 16 to the coating liquid holding unit 12 is set to 0.3 L/min or more and 0.5 L/min or less. Also, as an example, the speed at which the moving device 80 moves the cylindrical body 100 upward in the vertical direction is set to 2.0 mm/s or more and 6.0 mm/s or less.

Furthermore, in the first embodiment, as shown in Figures 5(A) to 5(C), the moving device 80 first moves the cylindrical body 100 downward in the vertical direction relative to the application liquid holding unit 12, and then moves the cylindrical body 100 upward in the vertical direction relative to the application liquid holding unit 12.

The supply amount and movement speed of the circulation unit 16 and the movement device 80 are preferably set so that when the cylinder 100 is moved vertically downward relative to the cylinder 100 (i.e., in the first movement step), the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylinder 100 is 10 mm/s or more and 200 mm/s or less. Furthermore, when the cylinder 100 is moved vertically downward relative to the cylinder 100 (i.e., in the first movement step), the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylinder 100 is more preferably 80 mm/s or more and 130 mm/s or less, and even more preferably 100 mm/s or more and 110 mm/s or less. As an example, when the cylinder 100 is moved vertically downward relative to the cylinder 100 (i.e., in the first movement step), the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylinder 100 is set to 100 mm/s.

<Action and effect>
Next, the operation and effects of this embodiment will be described.

The coating device 10 is provided with a coating liquid holding section 12 that has an upper opening 25 and a lower opening 28 and holds the coating liquid L. In the coating liquid holding section 12, a cylindrical body 100 is inserted through the upper opening 25 and the lower opening 28, and the cylindrical body 100 is moved upward in the vertical direction relative to the cylindrical body 100, thereby coating the coating liquid L onto the outer peripheral surface 100A of the cylindrical body 100.

More specifically, as shown in FIG. 5A, the cylindrical body 100 is inserted from above the coating liquid holding unit 12 in the direction of arrow A. With the lower end of the cylindrical body 100 inserted into the coating liquid holding unit 12, the coating liquid L is supplied to the coating liquid holding unit 12 by the circulation unit 16 (see FIG. 1), thereby filling the gap between the annular body 32 of the coating liquid holding unit 12 and the outer peripheral surface 100A of the cylindrical body 100 with the coating liquid L (supply step). Then, while the coating liquid L is being supplied to the coating liquid holding unit 12 by the circulation unit 16 (see FIG. 1), the cylindrical body 100 is moved downward (in the direction of arrow A) by the movement device 80 (see FIG. 1) (first movement step). At this time, the coating liquid L may be discharged from the discharge unit 36 so as to overflow from above the coating liquid holding unit 12, and the coating liquid L may also be allowed to flow downward from the lower opening 28.

As shown in Figure 5(B), while the circulator 16 (see Figure 1) supplies the coating liquid L to the coating liquid holder 12, the moving device 80 (see Figure 1) moves the cylindrical body 100 downward in the vertical direction (in the direction of arrow A), until the cylindrical body 100 reaches the lowest position.

Then, as shown in FIG. 5(C), the moving device 80 (see FIG. 1) moves the cylindrical body 100 upward (in the direction of arrow B) relative to the coating liquid holding unit 12 (second moving step). At this time, the coating liquid L is ejected from the ejection unit 36 so that the coating liquid L overflows from above. As a result, the coating liquid L flows downward from the lower opening 28, and is applied to the outer peripheral surface 100A of the cylindrical body 100 located above the upper opening 25. As a result, a coating film 102 is formed on the outer peripheral surface 100A of the cylindrical body 100 (see FIG. 6(B)).

In addition, in the coating device 10, a ring-shaped body 32 is disposed inside the coating liquid holding unit 12, and a cylinder 100 penetrates the ring-shaped body 32, penetrating the upper opening 25 and lower opening 28 of the coating liquid holding unit 12. As the cylinder 100 moves relative to the coating liquid holding unit 12, the coating liquid L held in the coating liquid holding unit 12 flows in from above and out from below between the ring-shaped body 32 and the cylinder 100. At this time, the ring-shaped body 32 moves relative to the coating liquid holding unit 12 along the installation surface 30, which intersects with the direction of the relative movement of the cylinder 100, so that the distance between the outer peripheral surface 100A of the cylinder 100 and the inner peripheral surface 32A of the ring-shaped body 32 becomes uniform along the circumferential direction.

The coating device 10 is provided with a container 14 that contains the coating liquid L that flows down from the coating liquid holding section 12. As a result, the coating liquid L flows downward along the outer peripheral surface 100A of the cylindrical body 100, and is collected in the container 14 (see Figure 3).

The coating device 10 is further provided with a circulation unit 16 that circulates the coating liquid L inside the container 14 to the coating liquid holding unit 12. In the circulation unit 16, by driving a pump 62, the coating liquid L inside the container 14 is supplied to the coating liquid holding unit 12 through a supply pipe 60.

For example, if foreign matter E (see Figure 3) is attached to the outer peripheral surface 100A of the cylindrical body 100, there is a concern that the outer peripheral surface 100A of the cylindrical body 100 may be coated with the coating liquid L while the foreign matter E remains attached.

In contrast, in the coating device 10 of the first embodiment, the supply amount and movement speed of the circulation unit 16 and the movement device 80 are set so that when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement process), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is 10 mm/s or more and 200 mm/s or less.

As a result, as shown in Figure 3, the coating liquid L flows down the outer peripheral surface 100A of the cylindrical body 100, washing away foreign matter E adhering to the outer peripheral surface 100A of the cylindrical body 100.

As a result, in the coating device 10, the occurrence of foreign matter defects in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 200 mm/s.

In addition, in the coating device 10, the supply amount and movement speed of the circulation unit 16 and the movement device 80 are set so that when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement process), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is 80 mm/s or more and 130 mm/s or less.

As a result, in the coating device 10, the occurrence of foreign matter defects in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 80 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 130 mm/s.

In addition, in the coating device 10, the supply amount and movement speed of the circulation unit 16 and the movement device 80 are set so that when the cylindrical body 100 is moved relatively upward in the vertical direction (i.e., in the second movement process), the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is 100 mm/s or more and 110 mm/s or less.

As a result, in the coating device 10, the occurrence of foreign matter defects in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is less than 100 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer surface of the cylinder is greater than 110 mm/s.

In addition, in the coating device 10, the moving device 80 moves the cylindrical body 100 vertically downward relative to the coating liquid holding unit 12, and then moves the cylindrical body 100 vertically upward relative to the coating liquid holding unit 12. Furthermore, the supply amount and moving speed of the circulation unit 16 and the moving device 80 are set so that when the cylindrical body 100 is moved vertically downward relative to the coating liquid holding unit 12 (i.e., in the first moving step), the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is 100 mm/s or more and 110 mm/s or less.

As a result, in the coating device 10, when the cylindrical body 100 is moved downward in the vertical direction relative to the cylindrical body, the occurrence of foreign matter defects in the coating film 102 on the outer peripheral surface 100A of the cylindrical body 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer peripheral surface of the cylindrical body is less than 10 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer peripheral surface 100A of the cylindrical body 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer peripheral surface of the cylindrical body is greater than 200 mm/s.

Furthermore, in the coating device 10, the moving device 80 moves the cylindrical body 100 in the vertical direction without changing the vertical position of the coating liquid holding unit 12.

As a result, the structure of the coating device 10 is simpler than in a configuration in which the coating liquid holding unit moves up and down without changing the vertical position of the cylindrical body.

In addition, in the coating device 10, a ring-shaped body 32 is disposed inside the coating liquid holding unit 12, through which the cylindrical body 100 penetrates. As the coating liquid L held in the coating liquid holding unit 12 moves relative to the cylindrical body 100, the ring-shaped body 32 flows in from above and out from below. The ring-shaped body 32 is installed so that it can move relative to the coating liquid holding unit 12 along an installation surface 30 that intersects with the direction of relative movement of the cylindrical body 100. As a result, when the coating liquid L flows between the ring-shaped body 32 and the cylindrical body 100 from above and out from below, the pressure of the coating liquid L causes the ring-shaped body 32 to move relative to the installation surface 30, making the distance between the outer peripheral surface 100A of the cylindrical body 100 and the inner peripheral surface 32A of the ring-shaped body 32 uniform along the circumferential direction.

As a result, in the coating device 10, unevenness in the thickness of the coating film 102 on the outer surface 100A of the cylindrical body 100 is reduced compared to when the annular body is fixed to the installation surface.

The coating method for applying a coating liquid using the coating device 10 also includes a supply step in which the lower part of the cylindrical body 100 is passed through the upper opening 25 and the lower opening 28 of the coating liquid holding section 12, and the coating liquid L is supplied to the coating liquid holding section 12 from the circulation section 16. The coating method also includes a first movement step in which the cylindrical body 100 is moved vertically downward relative to the coating liquid holding section 12, and the upper part of the cylindrical body 100 is positioned opposite the coating liquid holding section 12. The coating method also includes a second movement step in which the cylindrical body 100 is moved vertically upward relative to the coating liquid holding section 12, and the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is set to 10 mm/s or more and 200 mm/s or less, and the coating liquid L is applied to the outer peripheral surface 100A of the cylindrical body 100.

As a result, with this coating method, the occurrence of foreign matter defects in the coating film on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer surface 100A of the cylinder 100 is suppressed compared to when the relative speed at which the coating liquid flows down the outer surface of the cylinder is greater than 200 mm/s.

In addition, in the coating method, in the first movement step, the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 is set to 10 mm/s or more and 200 mm/s or less.

As a result, in the coating method, in the first movement step, the occurrence of foreign matter defects in the coating film on the outer peripheral surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer peripheral surface of the cylinder is less than 10 mm/s, and the occurrence of coating unevenness in the coating film 102 on the outer peripheral surface 100A of the cylinder 100 is suppressed compared to when the relative speed of the coating liquid flowing down the outer peripheral surface of the cylinder is greater than 200 mm/s.

In addition, in the coating method in which the coating liquid is applied using the coating device 10, the cylindrical body 100 is a cylindrical member or a cylindrical core material with an endless belt-like member wrapped around it.

As a result, when the coating liquid is applied to the outer peripheral surface of a cylindrical member or an endless belt-like member, the coating method suppresses the occurrence of foreign matter defects in the coating film 102 on the outer peripheral surface 100A of the cylindrical member or the endless belt-like member, and suppresses the occurrence of coating unevenness in the coating film 102 on the outer peripheral surface 100A of the cylindrical member or the endless belt-like member.

In addition, in the photoreceptor manufacturing method using the above coating method, the cylindrical body 100 is a metallic cylindrical member or a cylindrical core material with a metallic endless belt-like member wound around it, and the coating liquid L contains a photosensitive material.

As a result, when the coating liquid is applied to the outer peripheral surface of the photoreceptor, the coating method suppresses the occurrence of foreign matter defects in the coating film 102 on the outer peripheral surface of the photoreceptor, and suppresses the occurrence of coating unevenness in the coating film 102 on the outer peripheral surface of the photoreceptor.

Second Embodiment
Next, a coating apparatus 120 according to a second embodiment will be described with reference to Figures 7 and 8. Note that the same components as those in the first embodiment described above are given the same reference numerals and the description thereof will be omitted.

As shown in FIG. 7 , the coating device 120 includes a ring-shaped body 122 instead of the ring-shaped body 32 of the coating device 10 of the first embodiment. The inner diameter of the inner circumferential surface 122A of the ring-shaped body 122 is larger than the outer diameter of the cylindrical body 100, allowing the cylindrical body 100 to pass through the inside of the ring-shaped body 122.

As shown in Figures 7 and 8, the inner circumferential surface 122A of the annular body 122 has multiple inclined surfaces (two in this embodiment) formed at different angles relative to the vertical direction. In the second embodiment, the inner circumferential surface 122A of the annular body 122 has a first inclined surface 123A arranged on the upper side of the annular body 122 and a second inclined surface 123B arranged on the lower side of the first inclined surface 123A. The upper end of the second inclined surface 123B is connected to the lower end of the first inclined surface 123A. In addition, the inner circumferential surface 122A of the annular body 122 has a straight portion 123C arranged in the vertical direction from the lower end of the second inclined surface 123B.

As an example, the angle of the first inclined surface 123A relative to the vertical direction is larger than the angle of the second inclined surface 123B relative to the vertical direction. The other configuration of the coating device 120 is similar to the configuration of the coating device 10 of the first embodiment.

The above-mentioned coating device 120 has the same configuration as the coating device 10 of the first embodiment, and can achieve the same functions and effects.

〔supplementary explanation〕
In the first and second embodiments, the shape of the annular body may be changed, and the annular body may have no inclined surface on its inner peripheral surface. Furthermore, the configuration of each member of the coating liquid holding unit 12 may be changed as long as the configuration allows the coating liquid L to be applied to the outer peripheral surface 100A of the cylindrical body 100.

In the first and second embodiments described above, the circulation unit 16 is configured to circulate the coating liquid L between the coating liquid holding unit 12 and the container 14, but the present disclosure is not limited to this configuration. For example, the coating liquid L may be supplied to the coating liquid holding unit 12 without being circulated.

In the first and second embodiments described above, the moving device 80 is configured to move the cylindrical body 100 in the vertical direction without moving the coating liquid holding unit 12, but the present disclosure is not limited to this configuration. For example, the configuration of the moving unit and the operation of the relative movement can be changed as long as the cylindrical body 100 is moved in the vertical direction relative to the coating liquid holding unit 12.

Although the present disclosure has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that the present disclosure is not limited to such embodiments, and that various other embodiments are possible within the scope of the present disclosure.

The application device and application method of the present disclosure will be explained in more detail below using examples, but the application device and application method of the present disclosure are not limited to the following examples as long as they do not deviate from the gist of the disclosure.

In Examples 1 to 3, the relative speed V of the coating liquid L flowing down the outer peripheral surface 100A of the cylindrical body 100 was changed, and the coating liquid L was applied to the outer peripheral surface 100A of the cylindrical body 100, and the removal of foreign matter on the outer peripheral surface 100A of the cylindrical body 100 and the unevenness in the coating thickness were evaluated.

[Example 1]
<Preparation of coating solution>
(Preparation of Metal Oxide Fine Particles A)
100 parts by weight of zinc oxide (average particle size 70 μm: prototype manufactured by Teika Corporation) was mixed with 450 parts by weight of toluene and 50 parts by weight of methanol, and 0.25 parts by weight of a silane coupling agent (KBM 603: manufactured by Shin-Etsu Chemical Co., Ltd.) was added and dispersed in a sand grinder mill for 1 hour. The toluene was then distilled off under reduced pressure, and the mixture was baked at 150°C for 2 hours, cooled to room temperature, and crushed to obtain surface-treated zinc oxide.

(Preparation of coating liquid)
33 parts by weight of metal oxide fine particles A, 6 parts by weight of blocked isocyanate (Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), and 25 parts by weight of methyl ethyl ketone were mixed for 30 minutes, and then 5 parts by weight of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.), 3 parts by weight of silicone balls (Tospearl 145, manufactured by Toshiba Silicone Co., Ltd.), and 0.01 parts by weight of a leveling agent (silicone oil SH29PA, manufactured by Toray Dow Corning Silicone Co., Ltd.) were added to the above mixture, and the mixture was dispersed for 2 hours using a sand mill to obtain coating solution L.

The viscosity of the coating liquid L was 100 mPa·s, measured using an RE500H viscometer (manufactured by Tokiki Sangyo Co., Ltd.) under conditions of a standard cone (1°34′), 25° C., and a shear rate of 100 s ⁻¹ .

(Coating)
An aluminum pipe measuring φ84×340 mm was used as the cylinder 100, and coating was performed using the coating device shown in FIGS. 1 to 4 and the coating liquid L described above. The coating liquid L was constantly circulated and supplied to the coating liquid holding portion 12 at 0.4 L per minute, and to the cylinder 100 below the upper opening 25 at 0.4 L per minute. While constantly circulating and supplying the coating liquid L, the upper inner surface of the cylinder 100 was gripped with the gripping portion 86, and the cylinder 100 was forced to pass through the upper opening 25 provided in the coating liquid holding portion from above vertically at a constant speed of 500 mm per minute. By the time the cylinder 100 reached its lowest point, the coating liquid L had filled the coating liquid holding portion 12 and overflowed.

Next, the cylinder 100 was pulled up at a constant speed of 250 mm per minute, forming a coating film 102 (coating film) on the outer peripheral surface 100A of the cylinder 100. While the cylinder 100 moved up and down over the upper opening 25, the entire outer peripheral surface 100A of the cylinder 100 below the upper opening 25 was covered with coating liquid L discharged from the slit-shaped discharge port 36 provided in the upper opening 25, and the coating liquid L flowed down the outer peripheral surface 100A of the cylinder 100 due to gravity. When the cylinder 100 was moved upward relative to the coating liquid holder 12, the relative velocity V of the coating liquid L flowing down the outer peripheral surface 100A of the cylinder 100 was set to 10 mm/s. The sample coated with the coating liquid L (having the coating film 102 formed on the outer peripheral surface 100A of the cylinder 100) was then hot-air dried at 170°C for 40 minutes.

The coating thickness was measured using an eddy current coating thickness meter, with measurements taken at 20 mm intervals for 300 mm from the coating start position in the axial direction and at 90° intervals in the circumferential direction, and the coating thickness unevenness was evaluated from the difference between the average coating thickness and the maximum and minimum coating thickness values (range (Max-min)).
In Example 1, 100 coatings were performed, and the difference between the average film thickness of the 100 coatings and the maximum and minimum film thicknesses was evaluated. If the difference between the maximum and minimum film thicknesses was 1 μm or less, the coating unevenness was evaluated as good (◎); if the difference between the maximum and minimum film thicknesses was more than 1 μm but not more than 3 μm, the coating unevenness was evaluated as good (◎); if the difference between the maximum and minimum film thicknesses was more than 1 μm but not more than 3 μm, the coating unevenness was evaluated as bad (×). Furthermore, with regard to the state of foreign matter removal from the coating, if there was almost no foreign matter attached to the coating, the coating was evaluated as good (◎); if there was foreign matter attached to the coating but it was acceptable, the coating was evaluated as good (◯); and if foreign matter of an unacceptable size or number was found attached to the coating, the coating was evaluated as unacceptable (×). These results are shown in Table 1.

[Example 2]
When the cylindrical body 100 was moved upward in the vertical direction relative to the coating liquid holding portion 12, the relative speed V of the coating liquid L flowing down the outer surface 100A of the cylindrical body 100 was set to 100 mm/s, and the coating liquid L was applied in the same manner as in Example 1.

[Example 3]
When the cylindrical body 100 was moved upward in the vertical direction relative to the coating liquid holding portion 12, the relative speed V of the coating liquid L flowing down the outer surface 100A of the cylindrical body 100 was set to 200 mm/s, and the coating liquid L was applied in the same manner as in Example 1.

[Comparative Example 1]
When the cylindrical body 100 was moved upward in the vertical direction relative to the coating liquid holding portion 12, the relative speed V of the coating liquid L flowing down the outer surface 100A of the cylindrical body 100 was set to 8 mm/s, and the coating liquid L was applied in the same manner as in Example 1.

[Comparative Example 2]
When the cylindrical body 100 was moved upward in the vertical direction relative to the coating liquid holding portion 12, the relative speed V of the coating liquid L flowing down the outer surface 100A of the cylindrical body 100 was set to 210 mm/s, and the coating liquid L was applied in the same manner as in Example 1.

The results of evaluation of foreign matter removal and coating unevenness (i.e., coating thickness unevenness) on the outer peripheral surface 100A of the cylindrical body 100 are shown in Table 1.

As shown in Table 1, in Examples 1 to 3, it was confirmed that there was almost no unevenness in the thickness of the coating film 102 and that foreign matter removal was also favorable. In particular, in Example 2, there was good unevenness in the coating film 102 and foreign matter removal was also favorable.

In contrast, in Comparative Example 1, where the relative velocity V of the coating liquid L flowing down the outer peripheral surface of the cylinder was relatively small, foreign matter was found to be attached to the coating film on the outer peripheral surface 100A of the cylinder 100. In addition, in Comparative Example 2, where the relative velocity V of the coating liquid L flowing down the outer peripheral surface of the cylinder was relatively large, significant unevenness in the thickness of the coating film on the outer peripheral surface 100A of the cylinder 100 was found.

10 Coating device 12 Coating liquid holding section 16 Circulation section (an example of a supply section)
25 Upper opening 28 Lower opening 30 Installation surface 32 Ring-shaped body 80 Moving device (an example of a moving part)
100: Cylinder 100A: Outer circumferential surface 102: Coating film (an example of a coating film)
120 Coating device 122 Annular body L Coating liquid E Foreign matter

Claims (10)

a coating liquid holding section that includes an upper opening and a lower opening, holds a coating liquid, and applies the coating liquid to an outer peripheral surface of a cylindrical body by passing the cylindrical body through the upper opening and the lower opening and moving the cylindrical body upward in a vertical direction relative to the cylindrical body;
a supply unit that supplies the coating liquid to the coating liquid holding unit;
a moving unit that moves the cylindrical body relative to the coating liquid holding unit in a vertical direction;
Equipped with
The supply amount and movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved relatively upward in the vertical direction, the relative speed V of the coating liquid flowing down the outer surface of the cylindrical body is 10 mm/s or more and 200 mm/s or less. The coating device described in claim 1, wherein the supply amount and movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved upward in the vertical direction relative to one another, the relative velocity V of the coating liquid flowing down the outer surface of the cylindrical body is 80 mm/s or more and 130 mm/s or less. The coating device described in claim 2, wherein the supply amount and movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved upward in the vertical direction relative to one another, the relative velocity V of the coating liquid flowing down the outer surface of the cylindrical body is 100 mm/s or more and 110 mm/s or less. the moving unit is configured to move the cylindrical body downward in the up-down direction relative to the coating liquid holding unit, and then move the cylindrical body upward in the up-down direction relative to the coating liquid holding unit,
4. The coating device according to claim 1, wherein the supply amount and the movement speed of the supply unit and the movement unit are set so that when the cylindrical body is moved downward in the vertical direction relative to each other, the relative speed V of the coating liquid flowing down along the outer surface of the cylindrical body is 10 mm/s or more and 200 mm/s or less. The coating device described in any one of claims 1 to 4, wherein the moving unit moves the cylindrical body in the vertical direction without changing the vertical position of the coating liquid holding unit. The coating device according to any one of claims 1 to 5, further comprising an annular body inside the coating liquid holding unit through which the cylindrical body penetrates, and through which the coating liquid held in the coating liquid holding unit flows in from above and flows out from below as the annular body moves relative to the cylindrical body, the annular body being installed so as to be displaceable relative to the coating liquid holding unit along an installation surface that intersects with the direction of the relative movement. A coating method for coating a coating liquid using the coating device according to any one of claims 1 to 6, comprising:
a supplying step of passing a lower portion of the cylindrical body through the upper opening and the lower opening of the coating liquid holding portion and supplying the coating liquid from the supply portion to the coating liquid holding portion;
a first moving step of moving the cylindrical body downward in the up-down direction relative to the coating liquid holding portion so that an upper portion of the cylindrical body is positioned opposite the coating liquid holding portion;
a second moving step of moving the cylindrical body upward in the vertical direction relative to the coating liquid holding part, and setting a relative speed V of the coating liquid flowing down along the outer peripheral surface of the cylindrical body to 10 mm/s or more and 200 mm/s or less, and coating the coating liquid on the outer peripheral surface of the cylindrical body;
The coating method comprising the steps of: The coating method described in claim 7, wherein in the first movement step, the relative velocity V of the coating liquid flowing down the outer peripheral surface of the cylindrical body is set to 10 mm/s or more and 200 mm/s or less. The coating method described in claim 7 or claim 8, wherein the cylindrical body is a cylindrical member or a cylindrical core material around which an endless belt-like member is wound. A method for manufacturing a photoreceptor by using the coating method according to any one of claims 7 to 9, comprising the steps of:
the cylindrical body is a metallic cylindrical member or a cylindrical core member around which an endless metallic belt-like member is wound,
The coating liquid is a photosensitive material.