JPH03188455A - Production of electrophotographic sensitive body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing an electrophotographic photoreceptor, and more particularly to a method for manufacturing an electrophotographic photoreceptor using a dip coating method.

[Prior Art] The dip coating method has been widely used as a method of manufacturing electrophotographic photoreceptors, and the method basically involves lowering the object to be coated into the paint until it reaches the desired area. This is a method in which the object to be coated is immersed and then relatively raised at an appropriate speed.

This dip coating method is superior in terms of productivity and uniformity of film thickness compared to other coating methods as a method for manufacturing seamless drum-shaped photoreceptors, but it may depend on the properties of the paint used. It often causes coating unevenness and coating defects.

It is known that defects such as unevenness and streaks are particularly likely to occur when a paint containing finely dispersed pigments is applied in a thin layer of 10 m or less.

Causes include: - uneven paint flow rate in the paint bath, non-uniform paint composition in the paint bath, - agglomeration of pigments in the paint bath, but anisotropy in shape It is known that in the case of paints containing fine pigment particles dispersed in them, the negative effects of (1) caused by agglomeration of pigments are significant.In severe cases, the paint gels in parts of the paint bath or paint piping. As a result, coating may become impossible, which is a serious problem in the photoreceptor manufacturing process.

In general, countermeasures for this problem include: x) Adding a dispersant, pre-treating the paint and optimizing the particle size, and A) Introducing a stirring mechanism into the paint bath or piping. However, in the case of paints for electrophotographic photoreceptors, (2) is strongly restricted in terms of electrical properties, and (3), the IW stirring mechanism itself may cause coating defects. However, even when using an ultrasonic dispersion device, there are problems such as noise and heat generation, which is difficult to deal with practically.

[Problem to be solved by the invention 9fJ1 The purpose of the present invention is to improve the dip coating device,
An object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor that solves the above problems.

[Means for Solving the Problems, Effects] The present invention is characterized in that, in a method for manufacturing an electrophotographic photoreceptor by a dip coating method, a dip paint bath device is used whose inner surface in contact with the flowing paint is not smooth but uneven. It consists of a method for manufacturing an electrophotographic photoreceptor.

Furthermore, in the above invention, the paint is a pigment dispersion system,
The present invention also includes a method for manufacturing an electrophotographic photoreceptor in which the particle size of the pigment is 0.1 μm or less.

The method of the present invention prevents the development of paint agglomeration from the paint bath wall surface by making the inner surface in contact with the liquid of the paint bath uneven instead of smooth in a method of manufacturing an electrophotographic photoreceptor using a dip coating method. be.

Coagulation of paint in a paint bath begins to develop from the wall of the bath where the paint flow rate is slowest, but according to the apparatus of the present invention,
There is minute turbulence near the inner wall surface of the bath, which creates an agitation effect that prevents the development of paint agglomeration.As a result, the object being coated is always coated with a uniform paint, reducing unevenness and Paint film defects such as brushes and streaks are greatly reduced.

Since the shape of the unevenness depends on the shape and size of the paint bath, the flow rate and properties of the paint, the shape of the object to be coated, the coating conditions, etc., it cannot be determined in general, but coating by the method of the present invention is carried out. An example of a device for this purpose is shown in the drawing.

FIG. 1 is an overall view, and FIG. 2 is an enlarged view of the inner surface of the coating bath, where 1 is the object to be coated, 2 is the paint bath 3, and 4 is the pump.
5 is a filter, 5 is an air damper, 6 is a paint tank, 7 is an agitator, 8 is an inner surface of the coating bath 2, and 9 is a recess.

Figure 2 shows an example of a case where the inner surface has four parts, and the shape is usually hemispherical, the depth is 1 mm or more, and the diameter is 1 mm to 50 m.
It is about m.

Further, it is preferable that the distribution density of the recesses is arranged in the closest manner according to the diameter, but the distribution can also be tilted so that there are more recesses in the lower part and less in the upper part along the vertical direction of the paint bath.

It is also effective to provide not only four parts but also a convex part on the inner surface.
Furthermore, it is also effective to have concave portions and convex portions coexist.

An example of operating conditions using the coating apparatus shown in FIGS. 1 and 2 is shown.

Size of paint bath: φl 36mm x l 500
mm Inner surface unevenness: φ5 mm, depth 3 mm, 36 pieces/9 cm 2 Paint flow rate: 2. C) fL/min Object to be coated: φ80 mm x 1360 mm aluminum cylinder Coating speed: 800 mm/min [Example] Example 1 The conductive layer, undercoat layer, charge An electrophotographic photoreceptor was manufactured by coating a laminated electrophotographic photoreceptor consisting of four layers, a generation layer and a charge transport layer.

The paint bath used was of the above type and had a density of 36 recesses/9 cm2 with a diameter of 5 mm and a depth of 3 mm.For comparison, an electrophotographic bath coated with a paint bath with smooth inner surfaces was used. I made a prototype of the body.

The substrate was an aluminum cylinder with a diameter of 80 mm and a diameter of 60 mm. The composition of the paint used for each layer is shown below.

Conductive layer (film thickness 20 lm) Material #4: Conductive titanium oxide (particle size 0.5) Phenolic resin methyl cellosolve methanol subbing layer (film thickness 1 m) Material: Polyamide methanol n-butanol charge generation layer ( Film thickness O8 Materials: - The following disazo pigment 10 parts 60 parts 30 parts 2 m) (particle size 0.05 ILm) - 1.0 pm) 40 parts 20 parts 20 parts 20 parts 1 Part #4 = Styrene-acrylic resin 10 Part Chlorobenzene 80 parts When observing the coated surface, especially the surface coated with the charge generation layer, it was found that, as described below, 1. When coating according to the method of the present invention, even if continuous coating is performed, no unevenness occurs and there is little increase in the viscosity of the paint. was confirmed.

Concave portions Good Good Smooth Good Band-like concentration murabutyral resin methyl ethyl ketone charge transport layer (thickness 20 lm) Concave portions in 1 part and 98 parts 3.2 3.8 Smooth 3.2 9.7 In addition, these electrophotographic photoreceptors When images were evaluated using a copying machine having the processes of pre-exposure, negative secondary charging, image exposure, -component toner development, transfer, and cleaning, it was found that the electrophotographic photoreceptor manufactured by the method of the present invention produced halftone images. However, it was recognized that the uniformity was excellent.

Example 2 In the same manner as in Example 1, a laminated electrophotographic photoreceptor was coated using the following coating material to produce an electrophotographic photoreceptor.

Similarly, for comparison, a comparative electrophotographic photoreceptor was manufactured by coating all the layers using a paint bath with a smooth inner surface.

Conductive layer (film thickness 20 lm) Materials: Conductive titanium oxide (particle size 0.5 to 1.0 m final) 40 parts 20 parts 20 parts 20 parts Phenolic resin methyl cellosolve methanol subbing layer (film thickness 2 JLm) Materials : Resistant zinc (particle size 0.0 Bpm) 10 parts thermosetting urethane resin 5 parts methyl ethyl ketone 85 parts charge generation layer (film thickness 0.2 pLm) Materials: The following phthalocyanine pigment (particle size 0.15 m) 1 part butyral Resin 1 part Methyl ethyl ketone 98 parts Charge transport layer (film thickness 20 m) Materials: The following hydrazone compound 10 parts Styrene-acrylic resin 10 parts Chlorobenzene 80 parts Observing the coated surface, especially the charge generation layer coated surface and the undercoat layer coated surface. As will be described later, it was confirmed that coating according to the method of the present invention did not cause defects such as unevenness, bushes, and streaks on the coated surface, and that there was little increase in the viscosity of the paint.

In addition, these electrophotographic photoreceptors were subjected to pre-exposure, negative charge, image exposure using a semiconductor (laser = 780 nm),
- Component toner When images were evaluated using a laser beam printer having processes for development, transfer, and cleaning, it was found that the electrophotographic photoreceptor manufactured by the method of the present invention was 1
It was found that there were few image defects, and that no marks or fogging occurred even after durability.

Good with four parts Good Good Smooth Good Four parts with some unevenness 2.5 Smooth 2.5 2 , 8 3.2 Good with recesses Good with recesses 8.5 13.6 Smooth 8.5 32.3 Examples 3 In the same manner as in Example 1, a laminated electrophotographic photoreceptor was coated using the following coating material to produce an electrophotographic photoreceptor. The paint bath used had 50 protrusions with a diameter of 3 mm and a height of 79 cm.
For comparison, all layers were coated using a paint bath with a smooth inner surface to produce a comparative electrophotographic photoreceptor.

Conductive layer (thickness 2 ouLm) Material: Conductive titanium oxide (particle size 0.5-1.0 μm) 40 parts Phenol resin 20 parts Methyl cellosolve 20 parts methanol 20 Undercoat layer (thickness 1 pm) Material: Polyamide 10 parts methanol
60 parts n-butanol 30 parts Charge generation M (film thickness 0.2 ILm) Materials: The following disazo pigment (particle size 0.02 JLm) 1 part Butyral resin Methyl ethyl ketone 1 part 98 parts Charge transport layer (film thickness 20 ILm) Materials: The following Styryl compound: 10 parts Styrene-acrylic resin: 10 parts Chlorobenzene: 80 parts Observation of the surface on which the charge generation layer was applied revealed that defects such as unevenness, bushes, and streaks did not occur on the surface when coating according to the method of the present invention, as described later. It was also confirmed that the increase in viscosity of the paint was small.

Furthermore, when these electrophotographic photoreceptors were used in a copying machine having processes of pre-exposure, negative charge, image exposure, -component toner development, transfer, and cleaning, images were evaluated. The electrophotographic photoreceptor was found to have excellent uniformity even in halftone images.

Has convex portions Good Good Smooth Good Streak-like uneven Convex portions
4.5 6.0 ff'I4.5 11.3 Effects of the Invention] The method for producing an electrophotographic photoreceptor of the present invention is effective in dip coating using a paint containing a fine pigment dispersion system with strong cohesion. It has a remarkable effect of suppressing the occurrence of coating defects such as streaks, bumps, and unevenness on the coated surface.

[Brief explanation of drawings]

FIG. 1 is an overall view of an example of an apparatus for implementing the present invention, and FIG. 2 is an enlarged view of a coating bath having four parts on the inner surface. Reference numeral 1 indicates an object to be coated, 2 indicates a paint bath, 3 indicates a pump, 4 indicates a filter, 5 indicates an air damper, 6 indicates a paint tank, 7 indicates an agitator, 8 indicates an inner surface of the coating bath 2, and 9 indicates a recess. Inside view of mouth sludge 4ri e2 @P minute large view

Claims (1)

[Scope of Claims] 1. An electrophotographic photosensitive member manufacturing method using a dip coating method, characterized in that an immersion paint bath device is used whose inner surface in contact with the flowing paint is not smooth but uneven. How the body is manufactured. 2. The paint is a pigment dispersion system and the pigment particle size is 0.1
The method for producing an electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor has a particle diameter of .mu.m or less.