JPH0321372A - Coating apparatus - Google Patents

Abstract

PURPOSE:To uniformize the distance between a cylindrical body and a coating head by mounting not only the coating head, a position detection means and a position control means but also an operational control means. CONSTITUTION:When the rod of a cylinder 63 is extended and contracted, hands 60A, 60B respectively shake around support shafts 61, 61 in closing and opening directions. The cylinder 63 is operated in the closing direction when it is necessary to correct a position and the position of a hollow drum 1 is corrected by an X-Y axis control table 64 in such a state that the hollow drum 1 is grasped by the hands 60A, 60B. A screw shaft 66 is used in order to raise the hands 60A, 60B in synchronous relation to the drawing-up speed of the hollow drum 1. After this rising reaches a certain limit, the grasping of the hollow drum 1 due to the hands 60A, 60B is released and the hands can return to the initial position. By this method, excellent electrophotographic characteristics can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coating device that is suitably used to continuously coat a photosensitive liquid onto the outer surface of a hollow drum to obtain an electrophotographic photoreceptor.

[Conventional technology]

Known coating methods for manufacturing an electrophotographic photoreceptor by coating a photosensitive liquid onto a cylindrical outer surface include spray coating, dip coating, blade coating, roll coating, and slide hopper coating. ing.

However, in the spray coating method, the solvent evaporates before the photosensitive liquid ejected from the spray gun reaches the outer surface of the object to be coated, so dry and solidified particles adhere to the surface, resulting in a smooth coating surface. cannot be obtained, and it is also difficult to control the film thickness.

Further, the blade coating method and the roll coating method have the disadvantage that a uniform coating film cannot be obtained due to the viscosity of the coating liquid. Furthermore, although the dip coating method improves the above-mentioned difficulties in the smoothness of the coating surface and the uniformity of the coating film, control of the film thickness is governed by the physical properties of the coating liquid and the coating speed. Therefore, it is very important to adjust the coating liquid, but this adjustment is extremely difficult in practice, and the coating speed is also slow, resulting in poor productivity.

Regarding such a coating method, Japanese Patent Application Laid-Open No. 58-189061
The so-called slide hopper one-type coating method typified by No. 1 is suitable because it does not have the above-mentioned drawbacks. Also, JP-A-60
- No. 50537 also proposes a device that improves the dipping method and coats from an annular coating head.

[Problem that the invention attempts to solve]

When coating the outer surface of a target cylindrical body from the annular coating head shown in each of the above publications, it is important to keep the gap between the coating head and the outer surface of the cylindrical body uniform in the circumferential direction and the posture of the cylindrical body. It is extremely important how to match the axis of the head.

That is, if the gap is not uniform in the circumferential direction, the coating film thickness will be non-uniform in the circumferential direction, resulting in uneven electrophotographic characteristics.

Regarding the former uniformity of the gap between the cylindrical body and the coating head, Japanese Patent Laid-Open No. 60-50537 discloses that the uniformity can be solved by providing a position regulating roller on the coating head.

However, with this method, positioning cannot be performed unless the outer surface of the cylindrical body is constantly in contact with the rollers, and is therefore unsuitable for photosensitive drums that are sensitive to scratches. Furthermore, if a certain amount of clearance is maintained, the positioning accuracy will be adversely affected.

Therefore, the main object of the present invention is to not only make the distance between the cylindrical body and the coating head uniform in the circumferential direction, but also to prevent the outer surface of the cylindrical body from being scratched at all, so that the cylindrical body can be used as an electrophotographic photoreceptor. The object of the present invention is to provide a coating device that can obtain excellent electrophotographic properties.

[Means to solve the problem]

The above-mentioned problems include: a coating head disposed surrounding the outer surface of a cylindrical body for applying a coating liquid to the outer surface of the cylindrical body; a position detection means for detecting the outer surface or center axis position of the cylindrical body; A position adjustment means for adjusting the position of the application head on the cross section, and a position calculation control means for giving a position correction signal of the cylindrical body to the position adjustment means based on a position detection signal from the position detection means. It can be solved by

On the other hand, in the coating method targeted by the present invention, basically only the relative position between the cylindrical body and the coating head is important, so the position of the coating head is fixed and the position of the cylindrical body is adjusted. Good too.

[Effect]

In the present invention, the position of the cylindrical body, for example, its outer surface or center axis position, is detected, and the position of the coating head or the cylindrical body is corrected and controlled based on this detection signal, so that the outer surface of the cylindrical body and the inner surface of the coating head are The distance between them can be adjusted uniformly in the circumferential direction, thereby making the thickness of the coating film uniform in the circumferential direction. Furthermore, since positioning can be performed with high precision without using the position regulating rollers as described above, the photosensitive drum will not be damaged.

Incidentally, the coating apparatus of the present invention is particularly effective in obtaining an electrophotographic photoreceptor. The coating thickness of such an electrophotographic photoreceptor has a large effect on electrophotographic properties such as charge amount, sensitivity, and residual potential. Therefore, if the thickness of the coating film is non-uniform in the circumferential direction of the photosensitive drum, the image density within the same copy may become non-uniform or fog may occur. According to the present invention, the coating film thickness is uniform in the circumferential direction, so such problems do not occur at all.

Further, in the event that the cylindrical body is misaligned or tilted, the relative position between the application head and the cylindrical body is corrected, thereby preventing damage to the surface of the photosensitive drum, which is extremely sensitive to scratches.

[Specific structure of the invention]

The present invention will be explained in further detail below. Hereinafter, the cylindrical body referred to in the present invention will be taken as an example of a cylindrical body for an electrophotographic photoreceptor, that is, a hollow drum, but it does not matter whether it is hollow or solid. Further, the coating head referred to in the present invention may have a basic structure that is arranged around the outer surface of a cylindrical body and applies a coating liquid to the outer surface of the cylindrical body.
8-189061, Japanese Patent Application Laid-Open No. 60-50537, etc., or those illustrated below can be adopted as appropriate.

FIG. 3 shows a slide hopper type coating head as an example of the coating head IO of the present invention.

2 is a hollow drum, around which a coating head 10 is arranged to apply a coating liquid, that is, a photosensitive liquid L, to the outer surface of the hollow drum 1.

A narrow coating liquid distribution slit 12 having a coating liquid outlet 11 opening toward the hollow drum 1 is formed in the coating head 10 in the horizontal direction. This slit 12 communicates with a liquid reservoir header l3, and the photosensitive liquid L is supplied to this liquid reservoir header l3 by a pressure pump (not shown).

On the other hand, below the coating liquid outlet 1l of the slit l2, a liquid sliding surface 15 is formed so as to continuously slope downward and terminate at a dimension slightly larger than the outer dimension of the hollow drum l. Furthermore, a lip-shaped portion l6 is formed extending downward from the terminal end of this liquid sliding surface 15.

In such a coating device, in the process of pulling up the hollow drum 1, the photosensitive liquid L is pushed out from the slit 12 and the coating liquid outlet 11, and is caused to flow down along the liquid sliding surface 15. The photosensitive liquid L that has reached the lip portion 16 is applied to the outer surface of the hollow drum 1 with a thickness approximately corresponding to the clearance between the lip portion l6 and the hollow drum 1.

The coating head 10 itself is basically known, but in the present invention, in order to make the distance between the hollow drum l and the inner surface of the coating head 10 uniform in the circumferential direction, the apparatus configuration example shown in FIG. is taken.

That is, the position adjustment means 30 for the coating head 10 is provided on the pedestal 20 that supports the coating head IO. As this position adjustment means 30, a known X-Y axis control table can be used as is. The position adjustment means 30 is a coating head I.
O is connected to the coating head IO by a connecting member 31, and movement of the position adjustment means 30 in the X axis or Y axis directly affects the
It appears as an axis or Y-axis movement.

On the other hand, position detectors 40A to 40D for detecting the outer surface position of the hollow drum 1 are located at an uncoated position of the hollow drum 1, in this example below the coating head IO, and are spaced apart from the outer surface of the hollow drum 1. , and are arranged at intervals of 90 degrees in the circumferential direction, as clearly shown in FIG. For example, a laser displacement meter or an eddy current displacement meter is used as the position detectors 40A to 40D. The distance signals from each of the position detectors 40A to 40D between the outer surface of the hollow drum l and the outer surface of the hollow drum l are given to a computing unit 41, which calculates how the central axis of the hollow drum l deviates from the central axis of the coating head 10. Based on the result of this calculation, a position correction signal is given to the position adjustment means 30 via the controller 42 so that the two central axes coincide.

In this example, the position calculation control means referred to in the present invention is composed of a calculation unit 4l and a controller 42.

Furthermore, the output signals of the respective servo motors that drive the above-mentioned X-wheel=Y-axis control table 30 are input to the arithmetic unit 41 and given as the current position signal of the coating head 10.

In the coating device constructed in this manner, as shown in FIG.
The deviation in the X-axis direction is detected from the separation signal difference with respect to the outer surface of the hollow drum 1 given by the position detectors 40B and 40D, and thus the X-axis and Y-axis control table 30
The position of the coating head IO is corrected by comparing the current position of the coating head IO based on the output signal of each servo motor driving the servo motor.

In this case, if the position of the coating head 10 is adjusted so that the central axis of the hollow drum 1 and the central axis of the coating head 10 match, the distance between the hollow drum 1 and the inner surface of the coating head IO will be made uniform in the circumferential direction. , the coating film thickness becomes uniform.

Various types of means for adjusting the position of the coating head 10 can be employed as appropriate. For example, as shown in FIGS. 4 and 5, a fulcrum pivot 50 is provided on the pedestal 20, a first arm 5l is connected to this pivot 50, one end of which is pivoted to the flange 10a of the coating head 10, and the other , an X-axis-Yfdl control table 52 is disposed on the pedestal 20 so as to be movable in the X-axis and Y-axis directions, a second arm 53 and a third arm 54 are pivotally connected to the table 52, and the third arm 54 is First arm 51
I'll keep that in mind.

According to the position adjusting means according to this example, the coating head 10 can be moved in the direction of the arrow in FIG. 4 as the X-axis-Y-axis control table 52 moves in the X-axis or Y-axis.

On the other hand, in the present invention, the position of the coating head 10 may be fixed, and the position of the hollow drum 1 on its cross section may be corrected only when necessary. For this purpose, for example, the sixth
As shown in FIG. 7 and FIG. 7, a pair of hands 60A and BOB grip the hollow drum 1 from both sides, a substrate 62 that swingably holds the hollow drum 1 via support shafts 61 and 6l, and a base of the hand 60A1BOB. a cylinder 63 that connects the
An X-axis/Y-axis control table 64 that holds the substrate 62 and moves it along the X-axis and Y-axis, a holder 65 that holds the X-axis/Y-axis control table 64, and a screw that is screwed into the holder 65. A screw shaft 66, a driving means (not shown) for rotationally driving the screw shaft 66, and a screw shaft 66.
An elevating pedestal 67 for holding the is provided. 68 is a touch roller made of rubber or the like that comes into contact with the outer surface of the hollow drum l.

In such a device, when the rod of the cylinder 63 is expanded or contracted, the hands BOA and 60B are moved to support shafts 6l and 6, respectively.
It swings around l in the closing and opening directions. Therefore, when the position needs to be corrected, the cylinder 63 is operated in the closing direction, and the position of the hollow drum 1 is corrected by the X-wheel-Y-axis control table 64 while the hollow drum 1 is gripped by the hands 60A and 60B. Further, the screw shaft 66 is connected to the hand BOA in synchronization with the lifting speed of the hollow drum 1.
, 60B. When this rise reaches a certain limit, the grip of the hollow drum 1 by the hand 60A1BOB can be released and the hollow drum 1 can be returned to its original position.

The gripping and releasing by such hands 60A and 60B are
It can be used as a lifting means for hollow drums for continuous coating.

The present invention also includes simultaneously correcting the position of the coating head IO and the position of the hollow drum 1.

On the other hand, if another group of position detectors 40A to 40D is arranged at different heights relative to the hollow drum 1, the inclination of the hollow drum 1 can also be detected. In order to correct this inclination, the hand 60A. shown in FIGS. 6 and 7. 6
The inclination can be corrected by arranging another pair of 0Bs at different heights and by providing the above-mentioned mechanism for moving these in the X-axis and Y-axis.

By the way, when applying a photosensitive liquid, usually the application head I
The position of O is fixed and the hollow drum 1 is pulled up. In this case, instead of using the above-mentioned robot hand method, the hollow drum 1 can be pulled up by a means such as a cylinder by lifting the lower end of the hollow drum I or through a spacer drum, as described in Japanese Patent Application Laid-Open No. 61-25149. This can be done by

Furthermore, if necessary, it is also possible to reverse the positional relationship shown in FIG. 3 and apply the coating while lowering the hollow drum 1. Further, as described above, the structure of the coating head in the present invention is not limited as long as it has an annular structure.

As described above, the present invention is extremely effective as a coating device for manufacturing electrophotographic photoreceptors.

In this case, the photosensitive liquid may be one in which an inorganic photosensitive material such as zinc oxide or cadmium sulfide or an organic photosensitive material such as polyvinylcarbazole or trinitrofluorene is dispersed in a polymer binder. Furthermore, in recent years, in order to increase sensitivity and improve durability, functionally separated photosensitive layers in which a charge generation layer and a charge transport layer are laminated can also be used.

For example, the charge generation layer is made by dispersing an azo pigment, a quinone pigment, a perylene pigment, a cyanine pigment, an anthurone pigment, etc. in a polymeric binder such as polycarbonate, and the charge transport layer is made by dispersing a polycyclic aromatic compound, a nitrogen-containing cyclic compound, etc. can be obtained by dispersing it in a polymeric binder. The thickness of the charge generation layer is 0.601 to 10μ, preferably 0.05 to 5μ.
μ, and the thickness of the charge transport layer is preferably 5 to 30 μ. The age of the photosensitive liquid is in the range of 0.5 to 700 cp, preferably in the range of 1 to 500 cp.

Further, hollow drums for electrophotography include aluminum, stainless steel, plastic on which a conductive layer is formed, and the like. Alternatively, an undercoat layer and a charge generation layer may be formed in advance.

〔Effect of the invention〕

As described above, according to the present invention, since the distance between the cylindrical body and the coating head can be made uniform in the circumferential direction, when the cylindrical body is an electrophotographic photoreceptor, excellent electrophotographic properties can be obtained. I can do it. Furthermore, it is also possible to prevent scratches from forming on the outer surface of the cylindrical body.

[Brief explanation of drawings]

FIG. 1 is an overall schematic perspective view of an example of the apparatus of the present invention, FIG. 2 is a cross-sectional view showing the positional relationship between the position detector and the hollow drum, FIG. 3 is a longitudinal cross-sectional view of an example of the coating head, and FIG. 5 is a plan view of an example of a position adjusting means for a coating head, FIG. 5 is a front view thereof, FIG. 6 is a plan view of a position adjusting means for a hollow drum, and FIG. 7 is a front view thereof. l...Hollow drum, 10...Applying head 30...
Position adjustment means 40A to 40D...Position detector, 4l...Arithmetic unit 4
2... Controller 52... X-wheel-Y-axis control table 60A, 60B... Hand, 63... Opening/closing cylinder 64... X-axis-Y-axis control table, L... Photosensitive liquid. Figure 1 Figure 2 40D Jar Figure 3 Figure 4 Figure 5 Figure 6 Figure A

Claims (2)

[Claims] (1) a coating head disposed surrounding the outer surface of a cylindrical body for applying a coating liquid to the outer surface of the cylindrical body; and a position detection means for detecting the outer surface or central axis position of the cylindrical body;
a position adjustment means for adjusting the position of the coating head on the cross section of the cylindrical body; and a position calculation control means for supplying a position correction signal of the cylindrical body to the position adjustment means based on a position detection signal from the position detection means. A coating device characterized by comprising: (2) a coating head disposed surrounding the outer surface of the cylindrical body and applying a coating liquid to the outer surface of the cylindrical body; and a position detection means for detecting the outer surface or central axis position of the cylindrical body;
a position adjustment means for adjusting the position of the cylindrical body on a cross section of the cylindrical body; and a position calculation control means for supplying a position correction signal of the cylindrical body to the position adjustment means based on a position detection signal from the position detection means. A coating device characterized by comprising: