JP2924220B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photosensitive member by a dip coating method in which an object to be coated is immersed in a coating solution and then pulled up to perform coating. The present invention relates to a method for producing an electrophotographic photoreceptor by a dip coating method for minimizing troubles caused by coating film defects and unevenness in shading of the coating film.

[0002]

2. Description of the Related Art Hitherto, various methods of applying a coating liquid to an object to be coated such as a cylindrical body have been known, but particularly when importance is placed on the smoothness of a coating film such as an electrophotographic photoreceptor. A dip coating method is used. In general, in the dip coating method, an object to be coated is immersed in a coating liquid using a dip coating apparatus, and then is pulled up at an appropriate speed to perform coating. in this case,
For example, as described in JP-A-59-90667, it is preferable to provide a coating liquid recovery tank for collecting the coating liquid separately from the coating tank and to continuously circulate the coating liquid. This effectively achieves the object of preventing the fluctuation of the liquid level in the coating tank, making the composition of the coating liquid uniform, and preventing the surface of the coating liquid on the coating tank from being stained.

FIG . 3 is a schematic diagram of a conventional dip coating apparatus, in which an object 3 is immersed in a coating liquid 4 in a coating tank 1 for coating. The object to be coated is supported by a support 9 so as to move up and down by a motor 10 and a ball screw 11. The coating liquid 4 is supplied to the coating tank 1 by the pump 6 and the pipe 5. The coating liquid overflowing from the upper end of the coating tank is returned to the coating liquid recovery tank 2 through the guide tube 8.

[0004]

However, in the conventional dip coating apparatus as shown in FIG. 3 , an air flow flowing through the guide tube 8 is generated. As a result, the solvent vapor concentration near the surface of the coating liquid changes, and accordingly, uneven convection occurs on the coating surface, and as a result, there is a problem that a coating film formed has a coating film defect. Many of the coating film defects generated at that time were in the form of shading unevenness. Further, as described in JP-A-59-195243, a liquid reservoir,
That is, in the coating liquid recovery tank, a vertically extending partition wall having a gap for overflow at the bottom and top, respectively.
In the case of the staggered arrangement, when the air is replaced by the air vent holes, an air flow may be generated, and the structure is complicated. The present invention has been made in view of the above-described problems in the related art. Accordingly, an object of the present invention is to provide a dip coating method that does not cause a coating film defect.

[0005]

According to the method of manufacturing an electrophotographic photoreceptor of the present invention, a coating liquid for forming an electrophotographic layer is supplied from a coating liquid recovery tank into a coating tank, and a cylindrical substrate is placed in the coating liquid. The electrophotographic photosensitive member is manufactured by immersing and then pulling up to perform coating, wherein the coating tank
When the coating liquid overflowing from the upper edge of the coating tank is refluxed to the coating liquid recovery tank through the guide pipe, the coating liquid is retained in the middle of the guide pipe during coating.
The method is characterized in that the flow of air flowing together with the coating liquid is interrupted, and coating is performed in a state where the solvent vapor of the coating liquid is filled on the surface of the coating liquid.

In the present invention, the coating solution for forming an electrophotographic layer means a coating solution used for forming a coating layer constituting an electrophotographic photoreceptor, and includes only a photosensitive layer such as a charge generation layer and a charge transport layer. Instead, it may be a coating liquid used for forming an undercoat layer, an intermediate layer, a surface layer, and the like.

When dip coating is performed by the dip coating method of the present invention, the coating liquid is circulated between the coating tank and the coating liquid recovery tank, and the object is dipped in the coating liquid in the coating tank and pulled up. At this time, the coating liquid overflowing from the upper edge of the coating tank is held in the liquid receiving section, and is introduced into the coating liquid recovery tank through the guide tube. In the present invention, the upper portion of the coating tank is opened, and when the coating liquid overflowing from the upper edge of the coating tank flows through the guide pipe, the air flow flowing through the guide pipe causes the coating liquid to stay in the middle of the guide pipe.
To cut off. Specifically, blocking the flow of air by providing a bent portion on the guide tube.

As a result, the vicinity of the surface of the coating solution is filled with the solvent vapor of the coating solution, the concentration is kept constant, and the concentration fluctuation is stabilized, so that the occurrence of coating film defects is reduced.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a schematic configuration diagram of one example of a dip coating apparatus for carrying out the present invention, and includes a coating tank 1, a coating liquid recovery tank 2, and a means for supporting a cylindrical substrate 3 as an object to be coated. .
In the lower part of the coating tank 1, a pipe 5 for supplying the coating liquid 4 is provided.
And is in communication with the application liquid recovery tank via the pump 6. The upper outer peripheral surface of the coating tank, liquid receiver 7 for holding the coating liquid overflowing is formed and is disposed a guide tube 8 is provided between the liquid reservoir and the coating solution recovery tank The guide tube 8 has a bent portion 8 bent downward.
1 is provided. The cylindrical substrate 3 is supported by a support 9 so as to move up and down by a motor 10 and a ball screw 11.

When the coating liquid is applied to the cylindrical substrate by using the dip coating apparatus, the cylindrical substrate 3 is immersed in the coating liquid 4 in the coating tank 1 by driving the motor 10 and then at a predetermined speed. Pull up. The coating liquid overflowing from the upper end of the coating tank 1 passes from the liquid receiving section 7 through the guide pipe 8 to the coating liquid recovery tank 2.
, But in the present invention, it overflows from the coating tank.
Is filled with the bent portion 81 of the guide tube 8,
The flow of air through the inner tube 8 is cut off at the bend. in addition
Solvent vapor can be retained near the coating liquid surface
Become. As a result, the occurrence of the above-mentioned convection of the solvent on the surface of the coating liquid is reduced, and the occurrence of coating film defects is reduced accordingly.

Using the dip coating apparatus described above, a coating liquid for forming an undercoat layer consisting of 1 part of a polyamide resin, 5 parts of methanol, 3 parts of n-butanol and water 1 was coated on 100 aluminum drums. A coating liquid for forming a charge generation layer comprising 1 part of metal phthalocyanine, 0.3 equivalent of tetracyanoanthraquinodimethane (based on pigment), 1 part of polyvinyl butyral resin and 60 parts of cyclohexanone, and
Charge transport layer comprising 2 parts of N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] 4,4'-diamine, 3 parts of polycarbonate resin and 20 parts of monochlorobenzene An application solution for forming is sequentially applied by a conventional method and dried to form an electrophotograph having a photosensitive layer composed of an undercoat layer having a thickness of 0.1 μm, a charge generation layer having a thickness of 0.10 μm, and a charge transport layer having a thickness of 20 μm. A photoreceptor was produced.
When a visual inspection was performed on the formed photosensitive layer,
No irregularities or streaks were observed in any of the first to 100th samples. Further, these electrophotographic photoreceptors were mounted on a copying machine (FX2700 manufactured by Fuji Xerox Co., Ltd.), a halftone image was copied, and the image was visually observed. As a result, an image having a uniform density without density unevenness was formed. It was confirmed that.

FIG. 2 is a schematic structural view of another example of a dip coating apparatus embodying the present invention. In the dip coating apparatus shown in FIG. 2, a bent portion 82 bent upward is provided at a position near the liquid receiving portion 7 of the guide tube 8. In this dip coating apparatus, the coating liquid overflowing from the coating tank fills the guide tube between the liquid receiving portion 7 and the bent portion 82, so that the flow of air passing through the guide tube 8 is cut off at the bent portion. .

In the dip coating apparatus shown in FIG.
The flow of air through the guide tube 8 is cut off, and the solvent vapor in the vicinity of the surface of the coating liquid can be kept at a constant concentration, so that the occurrence of coating film defects can be reduced.

An electrophotographic photosensitive member having a photosensitive layer similar to that described with reference to FIG. 1 was produced using the dip coating apparatus having the structure shown in FIGS. 2 and 3 and evaluated. The results are shown in Table 1 below together with the case of FIG.

[0015]

[Table 1]

[0016]

Dip coating method of the present invention exhibits, as above, when recirculating the coating liquid in the coating liquid recovery tank, guide
Since dip coating is performed by stopping the flow of air through the guide tube by retaining the coating liquid in the middle of the pipe, the vicinity of the coating liquid surface is always filled with the solvent vapor of the coating liquid at a constant concentration. And concentration fluctuations are stabilized. Therefore,
This produces the effect of reducing the occurrence of coating film defects.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of a dip coating apparatus for carrying out the present invention.

FIG. 2 is a schematic configuration diagram of another example of a dip coating apparatus for carrying out the present invention.

FIG. 3 shows a dip coating apparatus used in a conventional dip coating method.
It is a schematic block diagram of a device.

[Explanation of symbols]

1: coating tank, 2: coating liquid recovery tank, 3: cylindrical substrate,
4 ... Coating liquid, 5 ... Piping, 6 ... Pump, 7 ... Liquid receiving part, 8
... Guide tube, 9 ... Support tool, 10 ... Motor, 11 ... Ball screw, 12 ... Control valve, 81 , 82 ... Bent part.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Bando 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside the Fujimatsu Rocks Takematsu Office (72) Inventor Takahiro Suzuki 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Fuji Rocks Co., Ltd. In-house (72) Inventor Sadao Okano 1600 Takematsu, Fuji Xerox Co., Ltd., Takematsu Plant, Minami-Ashigara, Kanagawa Prefecture (72) Inventor Masahiko Hozumi 1600 Takematsu Plant, Fuji Xerox Co., Ltd., Takematsu Plant, Minami-Ashigara, Kanagawa Prefecture (72) Inventor Seiji Ashiya 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Takematsu Office (56) References JP-A-63-6559 (JP, A) JP-A-59-195243 (JP, A) JP-A-2- 12155 (JP, a) JitsuHiraku flat 2-57174 (JP, U) (58 ) investigated the field (Int.Cl. ⁶ , DB name) G03G 5/05 102 B05D 1/18

Claims (3)

(57) [Claims] 1. An electrophotographic photoreceptor comprising: supplying a coating solution for forming an electrophotographic layer from a coating solution collection tank into a coating tank; immersing a cylindrical substrate in the coating solution; The coating tank
When the coating liquid overflowing from the upper edge of the coating tank is refluxed to the coating liquid recovery tank through the guide pipe, the coating liquid is retained in the middle of the guide pipe during coating.
A method for manufacturing an electrophotographic photoreceptor, comprising: interrupting the flow of air flowing together with a coating liquid to perform coating in a state where the solvent vapor of the coating liquid is filled on the surface of the coating liquid. 2. The method according to claim 1, wherein the stagnation of the coating liquid in said guide tube is determined by
2. The method according to claim 1, wherein the step is performed by a bent portion provided in the middle of the inner tube.
The method for producing the electrophotographic photosensitive member according to the above. 3. The method according to claim 1, wherein the stagnation of the coating liquid in the guide tube is determined by
2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the method is performed on a side of the inner tube near the coating tank .