JPH0832318B2 - Method for rotating and conveying hollow cylindrical body - Google Patents

Description

Detailed Description of the Invention Technical Field This conveying method relates to a method for rotary conveying a hollow cylindrical object without contacting the outer surface and an apparatus for realizing said method, and more specifically to a method and apparatus for coating a hollow cylindrical object, which is particularly advantageously applicable to processes such as spray coating, jet cleaning and drying of electrophotographic photosensitive drums and belts.

BACKGROUND ART When electrostatic spray coating is performed on cylindrical objects such as drums, the conventional method (JP-A-62-61672) involves holding each drum vertically and rotating it to coat the drum.

However, with this method, if the droplets applied to the drum are sprayed under conditions that allow them to be sufficiently leveled and form a smooth film, the droplets that adhere to the drum will flow down in the axial direction,
This results in uneven film thickness in the axial direction after drying. Furthermore, whether the drum is held vertically and rotated, or even held horizontally and rotated, conventional electrostatic spray coating, which attempts to coat each individual drum, results in a large potential gradient at the drum edges, resulting in increased deposition at the edges and uneven film thickness. To resolve this issue, dummy drums must be placed on either side of the target drum, but this reduces the efficiency of liquid deposition on the target drum. Furthermore, coating each individual drum requires a separate drum holding structure and rotation function, which is not only uneconomical but also results in a lack of symmetry with respect to the axial center of the drum, which impairs the uniformity of spray droplet deposition and causes droplets to adhere to the holding and rotation mechanism, making operational stability difficult.

Furthermore, in the case of spray coating, it is desirable to spray the liquid continuously from the spray head; if it is sprayed intermittently, the liquid will dry out, and the next time it is applied, some of the dried film inside the head will re-dissolve, becoming foreign matter and causing coating defects.
Therefore, continuous spraying is desirable, but in the prior art, a significant amount of liquid is wasted, resulting in high costs.

In order to solve these problems, we have conducted various studies and found that:
The present invention provides a method for rotating and conveying a hollow cylindrical body that can be advantageously applied to coating or surface treatment processes for objects to be coated or treated, and an apparatus for implementing the method.

Disclosure of the Invention In the present invention, flanges having a hole in the center are fitted onto both ends of a hollow cylindrical workpiece, a shaft is inserted through the hole in the flange, and the shaft is supported horizontally and rotated by a pair of rotating rollers that can move up and down and are provided at at least two locations on each end of the shaft, spaced apart by a distance equal to or greater than the length of one of the workpieces. The shaft has a relative shape that allows the workpiece to rotate substantially coaxially in relation to the holes in the flange, but the abutting parts of the rotating rollers have a circular cross section and a shape that allows the holes in the flange to pass easily through. A pusher is provided to move the workpieces on the shaft, and the workpieces are inserted sequentially through the holes in the flange from one end of the shaft, which is supported horizontally by the rollers and rotates around its axis, so that the front and rear ends of multiple flanged workpieces are arranged in contact with each other, and while rotating coaxially with the shaft, the workpieces are moved on the shaft in the feed direction by the pusher, and the works that reach the other end of the shaft are sequentially released from the shaft.

The shaft is supported and rotated by at least two rollers on the insertion side and at least two rollers on the removal side, and each roller can support or unsupport the shaft by contacting or removing from the shaft.
The flanged workpiece pushed by the pusher passes through the support portion of the shaft where the roller is not supported, and is handed over to the next pusher.

It is preferable to provide three or more pushers including a pusher ( _P1 ) for transferring the work from the short loading shaft to the main shaft, a pusher ( _P2 ) for moving the work at a constant speed on the shaft, and a pusher ( _P3 ) for feeding the work individually and removing it from the shaft, and to move _P1 and _P3 at a higher speed than _P2 , so that the work can be inserted and removed simultaneously while moving at a constant speed on the shaft.

An example of an apparatus for applying the method of the present invention will be described below in detail with reference to the drawings. 1 denotes a shaft,
2 is the workpiece, 3 is the flange, 4, 5, 6, and 7 are each a pair of support and rotating rollers, 8 (P ₁ ), 9, and 10
( _P2 ) 11, 12 ( _P3 ) are pushers, 13, 14 are loading shafts, and 15 is a spray head.

However, the method of applying the coating liquid to the workpiece is not limited to spraying.
Any method that can be used for coating can be employed, and in addition to spraying, methods such as multi-head coating, curtain coater coating, blade coating, and underside immersion coating may be selected depending on the case.

In particular, in the case of electrostatic spray coating, where interrupting spraying causes the spray head to dry out, a problem, applying the method of the present invention, which allows the workpiece to be continuously supplied to the shaft, is highly effective in eliminating waste of coating liquid.

Since the shaft is responsible for both guiding the workpiece in a straight line and transmitting rotation, it is desirable to use a shaft with a non-circular cross section, such as a spline shaft, and to have a corresponding flange hole shape in order to rotate the workpiece against the friction caused by the pusher.
Of course, if the flange hole and/or shaft are roughened so that the workpiece can be rotated evenly by the sliding resistance of both, there is no need to be particular about the shape of the shaft.

The loading shafts 13 and 14 are set on a linear way on a stand so that their level direction coincides with that of the shaft 1, and can be moved left and right by an air cylinder (not shown).

First, workpieces with flanges on both sides (in this case, aluminum drums for photosensitive coating) are set in 13 and 14 (of course, this can be easily automated with a robot).
Both shafts 5 and 6 rotate in synchronization with shaft 1, which rotates at a constant speed using an AC servo motor (not shown). The shaft is supported by support and rotation rollers 5 and 7 (hereinafter simply referred to as support rollers).
Five workpieces are set between the
First, the workpiece on the loading shaft 13 is pushed by the pusher 8
Then, the material is transferred over the support roller 4 to the shaft 1 side.
At this time, the pusher 11 pulls the rightmost drum away from the group and moves it past the support roller 6. When the workpiece passes the support rollers 4 and 6, the support roller
4, 6 rise to support the shaft, and at the same time support rollers 5, 7
The support rollers start to descend.
It is preferable that pairs of 5 and 7, 6 and 5 and 7, respectively, rise and fall simultaneously.

Pusher 9 pushes the flange portion of the workpiece at its left end, catching up with the workpiece being moved at a constant speed by pusher 10, and the two workpieces are connected at the same speed without any impact force. After connecting, pusher 10 moves away from the workpiece, stops temporarily, then moves rapidly in the opposite direction and waits near support roller 5. Pusher 9 pushes the group of workpieces at a constant speed, and when the left end passes support roller 5, pusher 10, which has been waiting, moves forward at a constant speed and pushes the flange being pushed by pusher 9 in parallel. After handing over to pusher 10, pusher 9 stops, moves rapidly in the opposite direction and waits near support roller 4. At this time, support roller 5 rises, and support roller 4 descends, ready to wait for the insertion of a new workpiece. When the next cycle begins, an air cylinder (not shown) is activated and the loading shaft 14
The workpiece on the other side is pushed by the pusher 8 past the support roller 4, and the above-mentioned operation is repeated.

Meanwhile, on the sending side, the workpiece that has passed over the support roller 6 is sent by the pusher 12 to the transfer device on the unloading side (equipped with shafts corresponding to the shafts 13 and 14) while the support roller 7 is descending.
11 returns to its original position and waits. When the workpiece passes the support roller 7, the support roller 7 rises and the support roller 6 descends. Thus, the unloading side also enters the next cycle.

The movements of the above support rollers are illustrated in FIG. 3, and the movements of the pushers are controlled so that the work always passes over the support rollers in the lowered position.

If the shaft is supported at only two points as in the above example, the problem of the shaft bending may occur depending on its length and rigidity, but in that case, it is preferable to control the movement of each support roller as shown in Figure 4, since the shaft can be supported at three or more points at all times. However, since the work can only pass above the support rollers when they are in the lowered position, in order to achieve support at three or more points at all times without reducing production efficiency, that is, without reducing the number of workpieces supplied to the shaft per unit time, as is clear from Figure 4, the movement of the workpiece must be completed in a shorter time, and the movement speed of the pusher must be increased.

Therefore, for example, as shown in Figs. 5 and 6, both ends of the shaft are extended, and one support roller 16 and one support roller 17 are added to each end, and accordingly, a pusher 18 and a
By adding 19 and controlling each support roller as shown in FIG. 7, the shaft can be supported at three or more points at all times without changing the moving speed of the pusher, which is preferable.
Furthermore, if the movement of each support roller is as shown in FIG. 8, the shaft can be supported at four or more points at all times.

Furthermore, the number of support rollers on each end of the shaft may be four or more if necessary, but regardless of the number of support rollers and their movement, the movement of each pusher should be controlled so that the work always passes over the support roller in the lowered position.

In Figures 3, 4, 7 and 8, when the line corresponding to each support roller is at a higher position, it indicates that the support roller is in a raised position and supporting the shaft, and when the line is at a lower position, it indicates that the support roller is in a lowered position and not in contact with the shaft.

The above operations are incorporated into a sequencer, which receives each positional information and automatically moves on to the next operation.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings are illustrative illustrations of embodiments of the present invention.

Figures 1 to 4 are drawings illustrating an example of an apparatus for carrying out the method of the present invention, which is an apparatus having two support rollers installed at each end of a shaft, and a method for controlling the same. Figure 1 is a plan view of the apparatus, Figure 2(A) is a front view of a portion of Figure 1, Figure 2(B) is a cross-sectional view taken along line I-I' in Figure 1, and Figures 3 and 4 are time charts illustrating a method for controlling the support rollers of the apparatus.

5 to 8 are drawings illustrating another example of an apparatus for carrying out the method of the present invention, which has three support rollers installed on each end of a shaft, and a method for controlling the same. FIG. 5 is a plan view of the apparatus, FIG. 6(A) is a front view of a portion of FIG. 5, FIG. 6(B) is a cross-sectional view taken along the line K-K' in FIG. 5, and FIGS. 7 and 8 are time charts illustrating a method for controlling the support rollers of the apparatus.

1... shaft, 2... work, 3... flange, 4,
5, 6, 7, 16, 17... Support and rotating rollers, 8, 18... Pusher ( _P1 ), 9, 10... Pusher ( _P2 ), 11, 12, 19...
Pusher (P ₃ ), 13, 14... Loading shaft, 1
5...Spray head.

Best Mode for Carrying Out the Invention The present invention will now be described in more detail with reference to the following examples.

(Example 1) An organic electrophotographic photoreceptor (OPC) was formed using the apparatus shown in the drawing.
Drums were manufactured.

The workpiece is an aluminum drum with an inner diameter of 78.5 mm, an outer diameter of 80 mm, and a length of 350 mm, with a clearance of 40 to 70 mm from the flange.
The spacing between support rollers 4, 5, 6, and 7 was 500 mm,
The interval between 6 was 2000 mm. The shaft was supported by 4 and 7, and the bending of the shaft with the workpiece attached was about 5 mm. The shaft rotation speed was 100 rpm, and the workpiece feed speed was 17.5 mm/sec.

Also, a spray head 15 is provided at the center of the support rollers 5 and 6.
(Mini Bell type manufactured by Nippon Ransburg) from the work surface to 15
The cap (a bowl-shaped rotating body for spraying the coating liquid, a part of the spray head) was set at a distance of 1500 mm.
Rotating at 0 rpm, -60,000 V applied to the cap, solid concentration 16 wt
% charge transfer layer solution was supplied at 400 ml/min and applied to the drum, the adhesion efficiency was 94% and the dry film thickness was 22.6 ± 0.5 μm.
It became m.

(Example 2) In manufacturing an OPC drum using the apparatus shown in the drawings, coating was carried out in both cases where the charge generating layer and the conductive layer were coated separately and then laminated, and where the photosensitizers for the charge generating layer and the conductive layer were mixed and coated as a single layer.

(1) Multilayer type The charge generating layer solution and the conductive layer solution were prepared as shown in Tables 1 and 2.

Common conditions: Cap diameter 73mmφ, Cap rotation speed 15,000rpm, Cap applied voltage -60kVolt, Shaving air pressure 1kg/ ^cm2
(gauge pressure), Workpiece: Aluminum drum 80mm (diameter) x 350mm (length) x 1mm (thickness), Rotation speed: 200rpm when applying, 60rpm when drying.

The distance between the cap and the center of the aluminum drum is 170 mm. When spray coating an OPC drum, an electrostatic sprayer is preferably used, in which the coating liquid outlet (negative electrode) is bowl-shaped and rotates at high speed around its axis, atomizing the coating liquid supplied to the bowl. An example of such an electrostatic sprayer is the ultra-high-speed rotating bell-type electrostatic sprayer manufactured by Japan Devilbiss Co., Ltd.
Examples include RAB-500, Trinity Industries Co., Ltd. Triniyubell 9-62 type 50φ 60φ, Nippon Ransberg Co., Ltd. Grooved Minibell + J3ST 73mmφ air motor, etc.

The diameter of the bowl is about 40 to 100 mm and the rotation speed is 1.0
The rotation speed is suitably selected from the range of 00 to 50,000 rpm, preferably 5,000
~30,000 rpm.

The voltage to be applied is preferably -10 to -100 kV.

When applying the charge generating layer liquid, the liquid supply rate is 44 ml/min.
The conveying speed was 110 mm/sec. The time required for the cap to pass in front of the drum was approximately 3 seconds.

The dry film thickness is 0.5 μm. By controlling the conveying speed, dry film thicknesses of 0.4 μm, 0.5 μm, and 0.6 μm were produced, and the hues were clearly different. The 0.1 μm film thickness was clearly distinguishable visually. The 0.5 μm film exhibited a nearly uniform hue, and it was found that the film thickness unevenness was within 0.1 μm.

When applying the conductive layer liquid, the liquid supply rate was 200 ml/min and the workpiece feed speed was 56 mm/sec. The time required for the cap to pass in front of the drum was approximately 6 seconds.

The dry film thickness (estimated value) is 20 μm. The film thickness in the axial and circumferential directions was measured using an eddy current film thickness meter, and all measurements were within 20 μm.
The error was within ±0.5 μm.

After coating the two layers, electrical properties were measured and image appearance was evaluated, but no difference was found between the values and those of the sample prepared by the conventional immersion method.

(2) Single layer type The method of preparing the solution is as shown in Table 3. The conditions are the same as those for the laminated type.

The liquid supply rate was 200 ml/min, and the workpiece feed speed was 55 mm/sec. The estimated dry film thickness was 20 μm. The actual measured value was 20 ± 0.
It was 6 μm.

After application, electrical properties were measured and image appearance was evaluated, but no difference was found between the samples prepared by the immersion method and the samples prepared by the immersion method.

The present invention is not limited to the above-described embodiment, but can also be applied to jet washing. In this case, a tunnel-shaped cover is installed at the position where the workpiece receives the jet of washing liquid to prevent the washing liquid from scattering. A nozzle is installed on the upper inner wall of the tunnel, close to the workpiece, and the liquid is collected by a nozzle opening on the lower inner wall of the tunnel.

[0013] INDUSTRIAL APPLICABILITY [0014] The present invention is particularly suitable for transporting workpieces when electrostatically spray coating is performed on the base tube of an organic electrophotographic photoconductor (OPC), and prevents dripping of droplets and uneven droplet adhesion due to changes in the potential gradient, thereby enabling coating to be performed with a uniform film thickness. Furthermore, because the shaft is always hidden inside the workpiece and the pusher is located away from the coating area, there is no risk of droplet adhesion, ensuring operational stability. Furthermore, because all workpieces are coated while being transported continuously and automatically at a constant speed, coating efficiency is improved and costs can be reduced, making the present invention highly useful in industry.

Claims (8)

[Claims] [Claim 1] A method for rotary conveying a hollow cylindrical workpiece without contacting its outer surface, characterized in that flanges having holes in their centers are fitted onto both ends of the hollow cylindrical workpiece, a shaft is inserted through the holes in the flange, and the shaft is supported horizontally and rotated by a pair of rotating rollers that can move up and down and are provided at at least two locations on each end of the shaft, spaced apart by at least the length of one of the workpieces, the shaft has a relative shape that allows the workpiece to rotate substantially coaxially in relation to the holes in the flange, but the abutting parts of the rotating rollers have a circular cross section and are shaped to easily pass through the holes in the flange, and a pusher is provided to move the workpiece on the shaft, and the workpieces are inserted sequentially through the holes in the flange from one end of the shaft that is supported horizontally by the rollers and rotates about its axis, arranging the front and rear ends of multiple flanged workpieces so that they are in contact with each other, and while rotating coaxially with the shaft, the workpieces are moved on the shaft in the feed direction by the pusher, and works that reach the other end of the shaft are successively detached from the shaft. [Claim 2] A rotary conveying method as described in claim 1, characterized in that three pushers are provided, including a pusher ( _P1 ) for inserting the workpiece into the shaft, a pusher ( _P2 ) for moving the workpiece at a constant speed on the shaft, and a pusher ( _P3 ) for removing the workpiece, and by operating pushers ( _P1 ) and ( _P3 ) at a speed faster than pusher ( _P2 ), the workpiece is inserted or removed simultaneously while it is moving at a constant speed, and the pushers are controlled so that the workpiece passes through a position on the shaft where it should contact the rotating roller that can be moved up and down when the rotating roller is in a lowered position. [Claim 3] A method for non-contact rotary transport and coating of a hollow cylindrical workpiece, characterized in that flanges having a hole in the center are inserted onto both ends of the hollow cylindrical workpiece, a shaft is inserted through the hole in the flange, and the shaft is supported horizontally and rotated by a pair of rotating rollers that can move up and down and are provided at at least two locations on each end of the shaft, spaced apart by at least the length of one of the workpieces, the shaft has a relative shape that allows the workpiece to rotate substantially coaxially in relation to the holes in the flange, but the abutting parts of the rotating rollers have a circular cross section and a shape that allows the holes in the flange to easily pass through, a pusher is provided to move the workpiece on the shaft, and a coating mechanism is provided in the middle of the shaft, and multiple flanged workpieces are inserted sequentially from one end of the shaft, which is supported horizontally by the rollers and rotates around its axis, through the holes in the flange so that the front and rear ends of the workpieces are arranged in contact with each other, and while rotating coaxially with the shaft, the workpieces are moved on the shaft in the feed direction by the pusher, and works that reach the other end of the shaft are successively detached from the shaft. [Claim 4] A rotary conveying coating method as described in claim 3, characterized in that the pushers include three pushers including a pusher ( _P1 ) for inserting the workpiece into the shaft, a pusher ( _P2 ) for moving the workpiece at a constant speed on the shaft, and a pusher ( _P3 ) for removing the workpiece, and by operating pushers ( _P1 ) and ( _P3 ) at a speed faster than pusher ( _P2 ), the workpiece is inserted or removed simultaneously while it is moving at a constant speed, and the pushers are controlled so that the workpiece passes through a position on the shaft where it should contact the rotating roller when the rotating roller, which can be moved up and down, is in a lowered position. 5. The rotary conveying coating method according to claim 3, wherein the coating mechanism is a coating mechanism that realizes a coating method selected from the group consisting of spray coating, multi-nozzle coating, and curtain coater coating. 6. The rotary conveying coating method according to claim 4, wherein the coating mechanism is a coating mechanism that realizes a coating method selected from the group consisting of spray coating, multi-nozzle coating, and curtain coater coating. 7. Claim 5, wherein the coating mechanism is a coating mechanism that realizes electrostatic spray coating.
The rotary conveying coating method according to item 1. 8. Claim 6, wherein the coating mechanism is a coating mechanism that realizes electrostatic spray coating.
The rotary conveying coating method according to item 1.