JPS60150053A - Coating method of substrate of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a uniform coat film without leaving coating striations in the spiral coating process of the substrate, etc., of an electrophotographic sensitive body by further coating the surface of the coating soln. applied on said substrate, with a solvent the same as that contained in the coating soln. CONSTITUTION:A roll-shaped electrophotographic sensitive body 1 having an endless continuous circumference is rotated in the arrow direction at a constant speed, and a coating soln. contg. a solvent is applied spirally to the body 1 from the left end toward the right end by using a mobile coater 2. Next, a solvent the same as that contained in the coating soln. is applied on the surface of the applied coating soln. by using a spray coater 8. As a result, even if coating striations 7 due to evaporation of the solvent are caused by the spiral coating, a uniform coat film can be obtained by refeeding the solvent from the spray coater 8 and allowing the spirally applied coating soln. to continue flattening action due to surface tension.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a spiral coating method, and is a coating method suitable for use in the production of recording media such as electrophotographic photoreceptors, and which enables a uniform coating film without leaving coating streaks. The present invention relates to a coating method for electrophotographic photoreceptor substrates and the like that can be obtained.

The present applicant previously disclosed a technique related to a spiral coating method (hereinafter referred to as the previously proposed technique) in Japanese Patent Application Laid-Open No. 52-119651. As a result of intensive research to further improve the previously proposed technology, the following problems were discovered.

That is, for example, when producing a recording medium such as an electrophotographic photoreceptor, a coating liquid is used in which a photosensitive material such as a pigment is dispersed or dissolved in a solvent, and the solvent has a relatively high evaporation rate. A solvent is used. Therefore, when applying fiL to the recording medium by spiral coating, the coating solution dries quickly due to solvent evaporation, so leveling due to surface tension cannot be achieved completely, leaving unevenness (coating streaks) on the coated surface. understood.

Therefore, in order to solve the above problem, it may be possible to incorporate excess solvent into the coating solution by incorporating the evaporated content in advance, but this will lower the viscosity of the coating solution and cause the coating film to become thinner. There is a problem in that it becomes difficult to regulate the thickness.

An object of the present invention is to provide a coating film V- for an electrophotographic photoreceptor substrate, etc., which allows a uniform coating film to be obtained without leaving coating streaks.

The above-mentioned object of the present invention is to provide a method for coating an electrophotographic photoreceptor substrate, etc., in which a coating solution using a solvent is applied in a spiral manner to a substrate having an endlessly formed continuous peripheral surface. This is achieved by further applying a solvent equivalent to the above-mentioned solvent on the coated surface formed by applying the above-mentioned solvent.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic perspective view showing one embodiment of the present invention, Fig. 2 is an enlarged schematic sectional view of a coating machine used in the above embodiment, and Fig. 3 is a schematic side view showing another embodiment of the present invention. It is a diagram.

In FIG. 1, reference numeral 1 denotes a base material having an endlessly formed continuous circumferential surface, and this embodiment shows a case where a roll-shaped electrophotographic photoreceptor base material is used as the base material 1. 2
is a coating machine, and in addition to using a liquid injection coating machine as shown in the figure, any coating machine such as a curtain coating machine may be used.The liquid injection coating machine 2 has a coating liquid passage 3 inside as shown in FIG. a flexible blade 5 fixed to the main body 4;
When a coating liquid is supplied to the coating liquid passage 3 through a supply pipe 6 by, for example, a pump (not shown), the coating film thickness is adjusted by the flexible blade 5 and the amount of liquid supplied.

When the base material 1 rotates at a constant speed in the direction of the arrow, a movable coating machine 2 performs spiral coating from the left end to the right end of the base material 1. At this time, if a solvent, particularly a solvent with a relatively high evaporation rate, is used, coating streaks 7 will occur for the reasons described above.

8 is a spray coating machine that applies a solvent equivalent to the above-mentioned coating solution solvent in order to flatten the coating streaks 7 as shown in "2".

The spray applicator 8 may be installed in parallel with the applicator 2 as shown in the figure and configured to move at the same speed as the applicator 41, or may be provided separately and moved at different speeds. It may be configured as follows. The width of the spray by the spray applicator 8 may be the same as or different from the width of the coating line 7, and the spray strength may be such that a leveling amount of solvent can be supplied without destroying the coating film. It may be determined as appropriate.

In addition, in the above, the coating machine 2 and the spray coating Ii8
It may be configured such that the base material l itself is moved without being moved.

The above description has been made regarding the case where the method of the present invention is applied to a roll-shaped base material 1, but in addition to this, it is also possible to apply the method to an endless strip-shaped base material 1 as shown in FIG. In FIG. 3, 9 is a roll, and lO is a tension roll.

Alternatively, a spiral coating method may be used, or any other arbitrary coating method may be used.

In the present invention, the term "solvent" includes, for example, a combination of one or more of various organic solvents, water, etc., and "solvents equivalent to the above-mentioned solvents" include the same solvents as well as those other than those listed above. It is recommended that the coating contains a wide range of solvents that can continue leveling the coating.

According to the present invention, even if a coating streak occurs due to solvent evaporation during spiral coating, a solvent equivalent to the evaporated solvent is resupplied, so that the spirally applied coating liquid can be applied to the surface. Since the leveling (flattening) effect by tension continues, a uniform coating film can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing one embodiment of the present invention, and FIG. 2 is an enlarged schematic sectional view of a coating machine used in the same embodiment.
FIG. 3 is a schematic side view showing another embodiment of the present invention. In the figure, l indicates a base material, 2 indicates a coating machine finish, 7 indicates a coating line, and 8 indicates a spray coating machine. Patent applicant: Konishiroku Photo Industry Co., Ltd. Agent: Nobuaki Sakaguchi (and one other person)

Claims (1)

[Claims] In a coating method for electrophotographic photoreceptor substrates, etc., in which a coating solution using a solvent is applied in a spiral manner to a substrate having an endlessly formed continuous peripheral surface, the coating solution is applied. A method for coating an electrophotographic photoreceptor substrate, etc., comprising further coating a solvent equivalent to the above-mentioned solvent on the coated surface.