JPH04274437A - Device for producing photosensitive body - Google Patents

Abstract

PURPOSE:To apply coating liquid without causing the flocculation of the coating liquid and stripe fault. CONSTITUTION:This is an annular applying device which annularly surrounds the periphery of a substance to be applied 1 having a cylindrical outer peripheral surface and applies the coating liquid to the outer peripheral surface thereof at a stage where the substance 1 is consecutively moved in a longitudinal direction, and further which is provided with an annular liquid storing chamber 21, a supply port 22 through which the coating liquid is supplied from the outside to a part of the chamber 21, and a slit which opens to the inside of the chamber 21. In such a device, a coating liquid stirring means 10 is provided at least at a part, where the liquid can be retained, in the chamber 21.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing drum-type or seamless belt-type photoreceptors for electrophotography and the like.

0002

2. Description of the Related Art Photoreceptors for electrophotography include hollow drum type ones made of aluminum or the like, and seamless belt type ones made of plastic sheets such as polyester on which metals such as aluminum are vapor-deposited.

On the other hand, in the case of a hollow drum type, coating methods for manufacturing an electrophotographic photoreceptor by coating the outer surface of the photosensitive liquid include spray coating method, dip coating method, blade coating method, roll coating method, Also known are the slide hopper coating method and the like.

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, resulting in dried and solidified particles adhering to the surface, which deteriorates the smoothness. It is difficult to obtain a good coating surface and it is 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.

In this regard, the use of an annular coating means, such as a slide hopper type coating device, has various advantages such as high productivity and easy control of film thickness.

On the other hand, this slide hopper type coating device, in the process of continuously moving an object to be coated having a cylindrical outer circumferential surface in its longitudinal direction, surrounds the object in an annular shape and applies pressure to the outer circumferential surface of the object to be coated. This coating device further includes an annular liquid pool chamber, a supply port for supplying the coating liquid from the outside to a part of the liquid pool chamber, and a supply port for supplying the coating liquid from the outside to a part of the liquid pool chamber. The coating liquid flowing out from the slit is allowed to flow down the liquid slide surface that is inclined diagonally downward, and the small gap between the slide edge at the lower end of the liquid slide surface and the outer surface of the object to be coated is formed. In this method, a bead is formed and transferred to the outer circumferential surface of the object as it moves.

In this case, aggregation may occur depending on the formulation of the coating solution, and if this aggregation occurs, a uniform film thickness may not be obtained. Therefore, the present applicant first proposed the
In Publication No. 93441, in addition to a supply port for the coating liquid, a discharge port for the liquid is provided in the liquid reservoir chamber, and further, the supply amount of the coating liquid necessary to obtain the desired film thickness is adjusted.
We proposed that an excess amount of coating liquid be supplied from the supply port and the excess amount be discharged from the discharge port.

[0008]

[Problems to be Solved by the Invention] Although the technique described in the above-mentioned publication is excellent in preventing agglomeration of the liquid and is effective in eliminating factors that deteriorate coating properties caused by aggregation, It is extremely difficult operationally to always obtain the desired thin film thickness by adjusting the discharge amount.
Place the supply port and discharge port at 180 degrees opposite positions, or as shown in Figure 2 of the same publication, set the supply port at 0 degrees and 180 degrees and the discharge ports at 90 degrees and 270 degrees. , there is no guarantee that the amount of liquid will be distributed uniformly in the left and right circumferential directions from the supply port, and therefore it is impossible to obtain a uniform film thickness in the circumferential direction.

[0009] When the coating liquid is supplied into the liquid pool chamber from one supply port, it may not be possible to prevent agglomeration in the liquid pool chamber, and the supply port The liquid distributed in the left and right circumferential direction collides with each other and stagnates there, resulting in a streak failure in which the coating film thickness protrudes in a streak-like manner from other parts or is depressed depending on the physical properties of the liquid, as shown in FIG.

[0010] Therefore, the main object of the present invention is to perform coating without causing agglomeration of the coating liquid and without causing streak failure.

[0011]

[Means for Solving the Problems] The above object is to provide an annular ring around the outer periphery of a cylindrical object to be coated in the process of continuously moving the object to be coated in the longitudinal direction thereof. The device further includes an annular liquid pool chamber, a supply port for supplying the coating liquid from the outside to a part of the liquid pool chamber, and an opening inward of the liquid pool chamber. In the annular coating device having a slit, the problem can be solved by providing a stirring means for the coating liquid in at least a portion of the liquid reservoir chamber where the liquid can remain.

[0012] In this case, it can be suitably applied to extrusion-type coating without a liquid surface in the liquid reservoir chamber, such as a slide hopper-type coating device, and in order to make the film thickness uniform in the circumferential direction, It is desirable to have no.

[0013] When there is only one liquid supply port, it is preferable that the stirring means is disposed at the liquid collision site, that is, at least on the opposite side of the supply port across the coating line.

[0014] The stirring means is disposed in the liquid reservoir chamber and has a ring-shaped stirring ring having irregularities in the circumferential direction on its surface, and a rotating means for continuously rotating the stirring ring in the circumferential direction. It can be done.

[0015]

[Operation] According to the present invention, since the stirring means for the coating liquid is provided at least in the part where the liquid may stagnate in the liquid reservoir chamber, the liquid is fluidized by the stirring means, thereby preventing the stagnation of the coating liquid. Even if the coating liquid is prone to agglomeration, the aggregation is prevented and a uniform coating film thickness can be obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail below with reference to the drawings.

In the present invention, for example, as shown in FIG.
In the process of continuously moving upward in the longitudinal direction, the coating liquid 3 is applied by the coating head 2 to the outer circumferential surface of the hollow drum 1 surrounding the hollow drum 1 in an annular manner.

This coating head 2 has an annular liquid reservoir chamber 2.
1, a supply port 22 for supplying the coating liquid 3 from the outside to a part of the liquid reservoir chamber 21, and a slit 23 opening inward of the liquid reservoir chamber 21.

On the other hand, below the coating liquid outlet of the slit 23, there is a liquid sliding surface 24 which is continuously inclined downwardly and terminates at a dimension slightly larger than the outer dimension of the hollow drum 1.
A lip-shaped portion 25 is further formed extending downward from the terminal end of this liquid sliding surface 24 .

When such a coating head 2 is used, the coating liquid 3 is pushed out from the slit 23 and flows down along the liquid sliding surface 24 during the process of lifting the cylindrical drum 1 . The coating liquid 3 that has reached the lip portion 25 is applied to the outer surface of the cylindrical drum 1 with a thickness approximately corresponding to the clearance between the lip portion 25 and the cylindrical drum 1.

In this way, when the coating liquid is supplied from one supply port 22 and the entire amount of the supplied coating liquid is applied to the outer surface of the hollow drum 1, as described above and as shown in FIG. At a position of 180 degrees with respect to the supply port 22, the supplied coating liquid stays in the liquid reservoir chamber,
For example, the coating film thickness may protrude, causing streak failure 3A.

In contrast, in the present invention, for example, FIG.
And as shown in FIG. 2, the coating liquid supply port 22
A stirring means 10, for example, a stirring blade, is disposed at a position 180 degrees from the base plate, and the coating liquid is forcibly fluidized at that position. This fluidizes the coating solution,
Its retention is prevented.

In the above example, as mainly shown in FIG. 1, when the coating liquid 3 in the liquid reservoir chamber 21 is supplied from the supply port 22, it separates to the left and right, and the separated liquid collides at the 180 degree position. This is an example of how to prevent stagnation caused by coating, but if the physical properties of the coating liquid are such that it tends to aggregate or settle, the film thickness distribution in the circumferential direction may be further improved by fluidization. In this case, as shown in FIG. 3, the stirring means 10, 10 can also be provided at other locations, for example at 90 degrees and 270 degrees.

On the other hand, the stirring means shown in FIGS. 4 and 5
As shown in FIG. 2, the stirring ring 11 may have a gear-like shape, the surface of which is uneven in the circumferential direction. This stirring ring 11 can be rotated around the center of the coating line by the output of a rotational drive motor 11B fixed to the coating head 2, which includes a rotational drive gear 11A that meshes with the stirring ring 11 in the liquid reservoir chamber 21.

Although the rotary drive gear 11A may be located at any position in the circumferential direction of the liquid reservoir chamber 21, it is preferably located at the supply port 22 in order to prevent the supply liquid from stagnation as much as possible. Further, in order to fluidize the liquid by the rotation of the stirring ring 11, irregularities are formed on its surface. It may be a surface, an upper surface or a lower surface, or a combination thereof.

In this embodiment, since the coating liquid 3 is fluidized throughout the liquid reservoir chamber 21, not only agglomeration of the liquid but also uneven distribution of the coating liquid is prevented.

The coating head according to the present invention is arranged on the outer surface of the hollow drum 1 so as to surround it.
If it has the basic structure of applying a coating liquid to the outer surface of
JP-A-58-189061, JP-A-60-50537
The information disclosed in the No. 1, etc. may be adopted as appropriate. As disclosed in Japanese Patent Application Laid-Open No. 62-83065,
Even a type in which the coating liquid is applied to the object to be coated by moving a group of seamless belts without extrusion can be effectively applied in terms of fluidizing the coating liquid and preventing agglomeration.

In addition to the hollow drum, the object to be coated may be a seamless belt type object.

As the photoreceptor, any known photoreceptor can be used as is in the production of an electrophotographic photoreceptor. As the photosensitive liquid, an inorganic photosensitive material such as zinc oxide or cadmium sulfide, or an organic photosensitive material such as polyvinylcarbazole and trinitrofluorene dispersed in a polymer binder can be used. In addition, in recent years, in order to increase sensitivity and improve durability, it can also be used to produce a functionally separated photosensitive layer in which a charge generation layer and a charge transport layer are laminated. When the photoreceptor is formed of multiple layers, one or more types of annular coating devices may be provided above the annular coating device for applying different coating liquids. The photoreceptor may also have a subbing layer or an electrogenerating layer. Therefore, the coating liquid targeted by the present invention includes not only the photosensitive material itself but also a coating liquid related to the production of a photoreceptor.

[0030]

As described above, the present invention has advantages such as being able to perform coating without causing agglomeration of the coating liquid and without causing streak failure.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view of an example of a coating device of the present invention.

FIG. 2 is a longitudinal sectional view thereof.

FIG. 3 is a horizontal cross-sectional view of another example.

FIG. 4 is a horizontal cross-sectional view of yet another example.

FIG. 5 is a view taken along the line 5-5 in FIG. 4;

FIG. 6 is a cross-sectional view showing the distribution of coating film thickness in the circumferential direction in a conventional example.

[Explanation of symbols]

1 Hollow drum 2 Application bed 3 Coating liquid 10, 11 Stirring means 21 Liquid pool chamber 22 Supply port 23 Slit

Claims (4)

[Claims] Claims: 1. In the process of continuously moving an object to be coated having a cylindrical outer peripheral surface in its longitudinal direction, a coating liquid is applied to the outer circumferential surface of the object by surrounding the object in an annular manner. The annular coating device further includes an annular liquid reservoir, a supply port for supplying a coating liquid from the outside to a part of the liquid reservoir, and a slit opening inward of the liquid reservoir. . A photoreceptor manufacturing apparatus, characterized in that a coating liquid stirring means is provided in at least a portion of the liquid reservoir chamber where the liquid can remain. 2. The apparatus according to claim 1, wherein the liquid reservoir chamber has no liquid surface and no liquid outlet. 3. The apparatus according to claim 1, wherein there is one liquid supply port, and the stirring means is disposed on the opposite side of the supply port across the coating line. 4. The stirring means includes a ring-shaped stirring ring disposed in the liquid reservoir chamber and having an uneven surface in the circumferential direction, and a rotating means for continuously rotating the stirring ring in the circumferential direction. 2. The device of claim 1.