JP2764435B2 - Coating device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus suitably used for obtaining an electrophotographic photosensitive member by continuously coating a photosensitive liquid on an outer surface of a hollow drum.

[Conventional technology]

As a coating method for manufacturing a electrophotographic photoreceptor by coating a photosensitive liquid on an outer surface of a cylindrical shape, a spray coating method, a dip coating method, a blade coating method, a roll coating method, a slide hopper coating method, and the like are known. ing.

However, in the spray coating method, since the solvent evaporates before the photosensitive liquid ejected from the spray gun reaches the outer surface of the object to be coated, the dried and solidified particles adhere to the surface, and the coating surface having good smoothness is obtained. And it is difficult to control the film thickness. Further, the blade coating method and the roll coating method have a disadvantage that a uniform coating film cannot be obtained due to the viscosity of the coating liquid.
Further, the dip coating method improves the above-mentioned problems of the smoothness of the coating surface and the uniformity of the coating film, but the control of the film thickness is governed by the physical properties of the coating solution and the coating speed. Therefore,
Although the adjustment of the coating solution is very important, this adjustment is extremely difficult in practice, and the coating speed is slow and the productivity is poor.

In contrast to such a coating method, a so-called slide hopper type coating method typified by JP-A-58-189061 is preferable because it does not have the above-mentioned disadvantages. Also, Japanese Patent Application Laid-Open No. Sho 60-50537 proposes an apparatus for applying a photosensitive liquid from an annular coating head by improving the dipping method.

[Problems to be solved by the invention]

From the annular coating head shown in each of the above publications, when applying the photosensitive liquid to the outer surface of the target cylinder, how to keep the gap between the coating head and the outer surface of the cylinder uniform in the circumferential direction,
It is very important to make the attitude of the cylindrical body coincide with the axis of the coating head.

That is, if the gap is not uniform in the circumferential direction,
The coating film thickness becomes non-uniform in the circumferential direction and appears as uneven electrophotographic characteristics.

Regarding the former uniformity of the gap between the cylindrical body and the coating head, Japanese Patent Application Laid-Open No. 60-50537 discloses that the coating head is provided with a position regulating roller to solve the uniformity.

However, such a means cannot be positioned unless the outer surface of the cylindrical body constantly contacts the rollers, and is not suitable for a photosensitive drum which does not like flaws. On the other hand, if a slight clearance is maintained, the positioning accuracy is adversely affected.

Therefore, the main object of the present invention is to not only make the separation 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 flawed at all, and when the cylindrical body is an electrophotographic photosensitive member. It is another object of the present invention to provide a coating apparatus capable of obtaining excellent electrophotographic characteristics.

[Means for solving the problem]

The object is to provide a coating head that is disposed on the outer surface of the cylindrical body so as to surround the outer surface of the cylindrical body and applies a coating liquid to the outer surface of the cylindrical body.
Position detecting means for detecting an outer surface or a center axis position of the cylindrical body, position adjusting means for adjusting a position of the coating head on a cross section of the cylindrical body, and the position based on a position detection signal from the position detecting means. The problem can be solved by providing the adjusting means with a position calculation control means for providing a position correction signal for the cylindrical body.

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 that the position of the coating head is fixed and the position of the cylindrical body is adjusted. Is also good.

[Operation] In the present invention, the position of the cylinder, for example, the outer surface or the center axis position thereof is detected, and the position of the coating head or the cylinder is corrected and controlled based on the detection signal.
The distance between the outer surface of the cylindrical body and the inner surface of the coating head can be uniformly adjusted in the circumferential direction, so that the coating film thickness in the circumferential direction can be made uniform. Furthermore, since the positioning can be performed with high accuracy without using the above-described position regulating rollers, there is no flaw on the photosensitive drum.

The coating apparatus of the present invention is particularly effective in obtaining an electrophotographic photosensitive member. The coating thickness of such an electrophotographic photoreceptor greatly affects electrophotographic characteristics such as the amount of charge, sensitivity and residual potential. Therefore, if the coating film thickness is not uniform in the circumferential direction of the photosensitive drum, the image density in the same copy becomes uneven or fogging occurs. According to the present invention, such a problem does not occur at all because the coating film thickness is uniform in the circumferential direction.

In addition, in the event that the cylindrical body is misaligned or tilted, the relative position between the coating head and the cylindrical body is corrected, so that the surface of the photosensitive drum, which is hard to be damaged, is prevented.

[Specific configuration of the invention]

Hereinafter, the present invention will be described in more detail. In the following, a cylindrical body for an electrophotographic photosensitive member, that is, a hollow drum is taken as an example of the cylindrical body in the present invention, but it does not matter whether it is hollow or solid. Further, as the coating head according to the present invention, if the coating head has a basic structure which is disposed on the outer surface of a cylindrical body so as to surround the same, and applies a coating liquid to the outer surface of the cylindrical body, the coating head disclosed in
No. 58-189061, Japanese Unexamined Patent Publication No. Sho 60-50537, etc., or those shown below can be appropriately employed.

FIG. 3 shows a slide hopper type coating head as an example of the coating head 10 of the present invention.

Reference numeral 1 denotes a hollow drum, around which a coating head 10 is arranged so that a coating liquid, that is, a photosensitive liquid L is coated on the outer surface of the hollow drum 1. The coating head 10 is formed with a narrow coating liquid distribution slit 12 having a coating liquid outlet 11 opening toward the hollow drum 1 in the horizontal direction. The slit 12 communicates with the liquid reservoir header 13, and the liquid reservoir header
The photosensitive liquid L is supplied to 13 by a pressure feed pump (not shown).

On the other hand, a liquid slide surface 15 is formed below the application liquid outlet 11 of the slit 12 so as to continuously incline in a downward constriction and terminate at a dimension slightly larger than the outer dimension of the hollow drum 1,
Further, a lip 16 is formed extending downward from the end of the liquid slide surface 15.

In such a coating apparatus, the photosensitive liquid L is extruded from the slit 12 and the coating liquid outlet 11 and flows down along the liquid slide surface 15 in the process of lifting the hollow drum 1. The photosensitive liquid L that has reached the lip 16 is applied to the outer surface of the hollow drum 1 with a thickness substantially corresponding to the clearance between the lip 16 and the hollow drum 1.

The above-mentioned coating head 10 itself is basically known, but in the present invention, in order to make the distance between the hollow drum 1 and the inner surface of the coating head 10 uniform in the circumferential direction, an example of the apparatus configuration shown in FIG. Is adopted.

That is, the position adjusting means 30 for the coating head 10 is provided on the gantry 20 that supports the coating head 10. This position adjusting means
As 30, a known XX axis control table can be employed as it is. The position adjusting means 30 includes the coating head 10 and the connecting member.
The movement of the position adjusting means 30 in the X-axis or Y-axis appears directly as the movement of the coating head 10 in the X-axis or Y-axis.

On the other hand, position detectors 40A to 40D for detecting the position of the outer surface of the hollow drum 1 are spaced apart from the outer surface of the hollow drum 1 at the unpainted position of the hollow drum 1, in this example, below the coating head 10. 2, and at intervals of 90 degrees in the circumferential direction, as clearly shown in FIG. Position detector
As 40A to 40D, for example, a laser displacement meter or an eddy current type displacement meter is used. The distance signal from each of the position detectors 40A to 40D to the outer surface of the hollow drum 1 is given to an arithmetic unit 41, and how the center axis of the hollow drum 1 is displaced with respect to the center axis of the coating head 10. Is calculated, and based on the calculation result, a position correction signal is given to the position adjusting means 30 via the controller 42 so that the two center axes coincide with each other. The position calculation control means according to the present invention comprises a calculator 41 and a controller 42 in this example. The output signal of each servo motor that drives the X-axis-Y-axis control table 30 is
And is given as a current position signal of the coating head 10.

In the coating apparatus configured as described above, as shown in FIG. 2, the position detectors 40B and 40D in the X-axis direction provide the distance signal difference from the outer surface of the hollow drum 1 provided by the position detectors 40A and 40C. 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, and is compared with the current position of the coating head 10 based on the output signal of each servomotor driving the X-axis-Y-axis control table 30. Then, the position of the application head 10 is corrected.

In this case, when the position of the coating head 10 is adjusted so that the center axis of the hollow drum 1 and the center axis of the coating head 10 coincide, the distance between the hollow drum 1 and the inner surface of the coating head 10 in the circumferential direction is made uniform. Thus, the coating film thickness becomes uniform.

Various means for adjusting the position of the coating head 10 can be appropriately employed. For example, as shown in FIGS. 4 and 5, a fulcrum pivot 50 is provided on the gantry 20, a first arm 51 is connected to the pivot 50, and one end thereof is pivotally attached to a flange 10a of the coating head 10, and An X-Y-axis control table 52 is provided on the gantry 20 so as to be movable in the X-axis and Y-axis directions, and a second arm 53 and a third arm 54 are pivotally mounted on the table 52, and a third arm 54 is provided. Is pivotally connected to the first arm 51.

According to the position adjusting means of this example, it is possible to move the coating head 10 in the direction of the arrow in FIG. 4 with the movement of the X-axis or Y-axis of the X-axis-Y-axis control table 52.

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 the cross-sectional view thereof may be corrected only when necessary. For this purpose, for example, as shown in FIGS. 6 and 7, a pair of hands 60A, 60B for holding the hollow drum 1 from both sides thereof and a substrate for holding the hollow drum 1 via the support shafts 61, 61 so as to be swingable. 62, hand 60A, 6
A cylinder 63 for connecting the base of OB, an X-axis-Y-axis control table 64 for holding and moving the substrate 62 in the X-axis and the Y-axis, and a holder 65 for holding the X-axis-Y-axis control table 64 A screw screw shaft 66 screwed to the holder 65, a driving means (not shown) for driving the screw shaft 66,
An elevating mount 67 that holds the screw shaft 66 is provided. Reference numeral 68 denotes a touch roller made of rubber or the like which comes into contact with the outer surface of the hollow drum 1.

In such a device, when the rod of the cylinder 63 expands and contracts, the hands 60A and 60B swing about the support shafts 61 in the closing and opening directions, respectively. Therefore, when position correction is necessary, the cylinder 63 is operated in the closing direction,
With the hollow drum 1 held by A and 60B, the X-axis-Y
The position of the hollow drum 1 is corrected by the shaft control table 64. The screw shaft 66 is used to raise the hands 60A and 60B in synchronization with the lifting speed of the hollow drum 1. If this rise reaches a certain limit, hand 60
The grip of the hollow drum 1 by A and 60B can be released, and the hollow drum 1 can be returned to the original position again.

The gripping and releasing by the hands 60A and 60B can be used as a means for lifting the hollow drum for continuous application.

In the present invention, the correction of the position of the coating head 10 and the correction of the position of the hollow drum 1 are simultaneously performed.

On the other hand, if the group of position detectors 40A to 40D is arranged on the hollow drum 1 so as to be different from each other in the height direction, the inclination of the hollow drum 1 can also be detected. In order to correct this inclination, the pair of hands 60A and 60B shown in FIGS. 6 and 7 are arranged so as to be different from each other in the height direction, and these are moved to the X axis and the Y axis. The inclination correction can be performed by providing the above mechanism.

By the way, when applying a photosensitive liquid, usually a coating head is used.
Fix the position of 10 and pull up the hollow drum 1. In order to raise the hollow drum 1 in this case, instead of the above-mentioned robot hand method, as described in JP-A-61-25149, the lower end of the hollow drum 1 or a means such as a cylinder via a spacer drum is used. Can be performed. If necessary, it is also possible to reverse the positional relationship shown in FIG. 3 and apply while lowering the hollow drum 1. Furthermore, 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 producing an electrophotographic photosensitive member. As the photosensitive liquid in this case, an inorganic photosensitive material such as zinc oxide or cadmium sulfide, or a liquid in which an organic photosensitive material such as polyvinyl carbazole and trinitrofluorene is dispersed in a polymer binder can be used. In recent years, a function-separated type photosensitive layer in which a charge generation layer and a charge transport layer are laminated can be used in order to increase sensitivity and improve durability.

For example, the charge generation layer disperses an azo pigment, a quinone pigment, a perylene pigment, a phthalocyanine pigment, an anthranthrone pigment, etc. in a polymer binder such as polycarbonate,
The charge transport layer can be obtained by dispersing a polycyclic aromatic compound, a nitrogen-containing cyclic compound and the like in a polymer binder. The thickness of the charge generation layer is 0.01-10 μm, preferably 0.05-5 μm, and the thickness of the charge transport layer is preferably 5-30 μm. The year of the photosensitive solution is in the range of 0.5 to 700 cp, preferably 1 to 500 c
range of p.

Examples of the hollow drum for electrophotography include aluminum, stainless steel, plastic on which a conductive layer is formed, and the like. Further, an undercoat layer or a charge generation layer may be formed first.

〔The invention's effect〕

As described above, according to the present invention, the separation distance between the cylindrical body and the coating head can be made uniform in the circumferential direction. Therefore, when the cylindrical body is an electrophotographic photosensitive member, excellent electrophotographic characteristics can be obtained. Can be. Further, it is possible to prevent the outer surface of the cylindrical body from being scratched.

[Brief description of the 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. The figure is a plan view of an example of the position adjusting means of the coating head, FIG. 5 is a front view thereof,
FIG. 6 is a plan view of the position adjusting means of the hollow drum, and FIG. 7 is a front view thereof. 1 Hollow drum 10, Coating head 30 Position adjusting means 40A to 40D Position detector 41 Computing unit 42 Controller 52 X-axis / Y-axis control table 60A, 60B Hand, 63: open / close cylinder 64: X-axis / Y-axis control table, L: photosensitive liquid.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuyuki Shimizu 1 Sakuracho, Hino-shi, Tokyo Konica Corporation (58) Field surveyed (Int.Cl. ⁶ , DB name) B05C 5/02 G03G 5 / 05 102 B05C 13/00

Claims (2)

(57) [Claims] A coating head disposed on and surrounding the outer surface of the cylindrical body for applying a coating liquid to the outer surface of the cylindrical body; position detecting means for detecting an outer surface or a center axis position of the cylindrical body; Position adjusting means for adjusting the position of the coating head on the cross section of the head, and position calculation control means for providing a position correction signal of the cylindrical body to the position adjusting means based on a position detection signal from the position detecting means. A coating device characterized by the above-mentioned. 2. A coating head disposed on an outer surface of a cylindrical body so as to surround the outer surface of the cylindrical body to apply a coating liquid to the outer surface of the cylindrical body, position detecting means for detecting an outer surface or a center axis position of the cylindrical body, and a cylindrical body. Position adjusting means for adjusting the position of the cylindrical body on the cross section of the body, and position calculation control means for providing a position correction signal of the cylindrical body to the position adjusting means based on a position detection signal from the position detecting means. A coating device characterized by the above-mentioned.