JPS5964847A - Production of electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor of a function snpn. type having a charge transfer layer wherein the surface characteristic is satisfactory by using a polymer contg. styrene or methyl methacrylate and coating the same at a specific soln. concn. and coating speed thereby forming the charge transfer layer. CONSTITUTION:The viscosity of a soln. prepd. by dissolving a polymer or copomer contg. styrene or methyl methacrylate and a charge transferrable material is adjusted to 50-300cP viscosity and is coated on the charge generation layer of an electrophotographic receptor of a function sepn. type having the charge transfer layer and the charge generating layer at <=40cm/min coating speed to form the charge transfer layer in a stage for dip coating said soln. on the charge transfer layer of said photoreceptor. The viscosity N (cP) and pulling speed S(cm/m) are related to each other inversely proportionally and a specified thickness of the film is obtd. at S=A/N (A is a constant ranging 300-3,000). A is the constant determined by the kind of the resin and charge transfer material used and a desired film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrophotographic photoreceptor, and more particularly, to a method for coating a charge transport layer of a functionally separated electrophotographic photoreceptor having a charge transport layer and a charge generation layer. be.

Organic photoconductive materials have advantages over inorganic photoconductive materials, such as being non-polluting and highly productive, but their low sensitivity has made it difficult to put them into practical use. For this reason, several sensitization methods have been proposed, but it is known that an effective method is to use a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated.

The charge generation layer is made of azo pigments such as Sudan Red, Guianpuru, and Jenas Green B, Algol Yellow,
Quinone pigments such as hillenquinone and indanthrene brilliant violet RRP, quinocyanine pigments, rylene pigments, indigo pigments such as indigo and thioindigo, bisbenzimidazole pigments such as India Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine, quinacridone pigments, etc. It is formed by dispersing a charge-generating substance in a binder resin such as polyester, polystyrene, fatty acid cellulose ester, polyvinyl acetate, acrylic, polyvinylpyrrolidone, methylcellulose, hydroxypropylmethylcellulose, or polyvinyl butyral, and coating it on a substrate. .

The charge transport layer provided on the charge generation layer contains a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene, or indole, carbazole, etc. in the main chain or side chain.
Oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline,
It is formed by dissolving a charge-transporting substance such as a compound having a nitrogen-containing cyclic compound such as thiadiazole or triazole, or a hydrazone compound in a resin that has film-forming properties. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself. Examples of such resins include polyester, polysulfone, polycarbonate, polymethacrylic acid esters, polystyrene, and styrene-acrylonitrile copolymer. Among these resins, it is preferable to use styrene or a polymer or copolymer of methyl methacrylate in consideration of electrophotographic properties such as film-forming properties, potential, sensitivity, and photomemory effect.

Examples include EVA, polystyrene, polymethyl methacrylate, styrene methyl methacrylate copolymer, styrene acrylonitrile copolymer, styrene butadiene copolymer, methyl methacrylate butyl methacrylate copolymer.

Methods for forming the charge transport layer include coating methods such as spraying, roll coater, bar coater, knife coater, blade coater, and dipping. A dip coating method is suitable as a simple coating method that provides a smooth surface. The application process is shown in the attached drawing.

The purpose of the present invention is to set conditions that will provide the best surface properties in terms of the relationship between the viscosity of the coating liquid and the lifting coating speed when applying a charge transport layer by a dip coating method. The thickness of the layer contributes to acceptance potential, sensitivity, etc., and is usually selected in the range of about 10 to 20μ, but in order to achieve this thickness by dip coating, the viscosity and pull-up coating speed must be kept at a certain level. There is a relationship.

That is, it was found that the larger the values of both viscosity and coating speed, the thicker the film becomes.If the film thickness is T1, the viscosity is N1, and the coating speed is 8, it was found that there is a relationship of TccN8. Therefore, in order to obtain the desired film thickness, increase the coating speed when the viscosity of the coating liquid is low, and decrease the coating speed when the viscosity is high.
do it.

However, as a result of the inventor's experiments, in the case of a coating liquid containing a polymer or copolymer of styrene or methyl methacrylate, if the viscosity is lower than 50 cP (centipoise), it is necessary to set the coating speed to f40 crn/min. Not,
It was found that when applied under these conditions, the vertical unevenness of the coating film thickness was 2 μ or more, and the potential unevenness of the photoreceptor became large, making it unsuitable for practical use. Furthermore, since the proportion of solvent was high, dew condensation could occur due to drying of the solvent from the coating film during pulling.

It was also found that when the viscosity is higher than 300 cP, the film thickness becomes too thick no matter how slow the coating speed is, and this is also not suitable for practical use.

In the present invention, when dip coating the charge transport layer, the viscosity of the coating liquid is adjusted to a pressure range of 50 to 300 cP, and the coating speed is adjusted to 40 cP.
It is characterized by coating at a rate of 1yR/min or less. The coating speed is determined to be 401 M/min or less in consideration of productivity.

Also, since it is TOCNEI, in order to obtain a constant film thickness, K
Since N and S are inversely proportional, it is expressed as S=Δ. Here A is a constant in the range of 300 to 3000,
It was found that this is determined by the type of resin and charge transport material used, and the desired film thickness. These numerical values will be explained using examples.

According to the present invention, the charge transport layer is formed using a styrene- or methyl methacrylate-containing polymer with a solution viscosity of 5.
0 to 300 cP, pulling coating speed of 40(7) or less than 7 minutes, and coating with the relationship S=A/N (A=300 to 3000) provides a smooth and uniform surface with good charge transport properties. The layer was successfully formed.

6- Example 1 Cylindrical 80φ with one end closed as shown in the attached drawings
The substrate was an aluminum cylinder of x 300+nm. This is made of polyamide resin (product name: Amilan C'M8
A 4% methanol solution of 00 [1, Toshi Co., Ltd.] was applied by the dipping method at a pull-up coating speed of JID cm/min, and the temperature was 80°C.
Heat drying was performed for 0 minutes to form an undercoat layer with a thickness of 0.6 μm.

Next, 10 parts (parts by weight, the same shall apply hereinafter) of a bisazo pigment with the following structural formula were added to polyvinyl butyral resin (trade name: Eslec BXL).
, manufactured by Tanemizu Kagaku ■) and 60 parts of cyclohexane 2F were dispersed over 20 hours using a sand mill apparatus using 1φ glass beads. Add methyl ethyl ketone (
100 parts of MKK) were added to prepare a coating liquid. This was applied using a dip coating method at a pulling rate of 10 crn/min.
A charge generation layer of 0.07 μm was formed by drying at 80° e for 10 minutes.

7 parts of a hydrazone compound having the structural formula represented by and 10 parts of a polystyrene resin (trade name: Dialex H, F-55; manufactured by Mitsubishi Monsando Kasei) were dissolved in monochlorobenzene. Table 1 shows the relationship between parts by weight of monochlorobenzene and solution viscosity.

Table 1 Using these solutions, coating was performed by dipping so that the film thickness after drying was 16 μm. Table 2 shows the relationship with the pulling speed.

As shown in Table 2, good results were obtained when the viscosity was 250.120.6Q (cP). In addition, the value of at this time is 1
It was 5DO.

A charge transport layer was coated on the charge generation layer under the conditions shown in Table 2, and dried at 100° C. for 1 hour to obtain an electrophotographic photoreceptor.

The thus produced electrophotographic photoreceptor was subjected to 5.6KV corona charging, image exposure, dry toner development, toner transfer to plain paper, and urethane rubber blade (hardness 70°, pressure 5gw/
cm, angle to the photoconductor (20') 9- When I installed it in an electrophotographic copying machine that has a cleaning process, etc., I was able to obtain good quality copy images with the viscosity other than 350F, but with the viscosity of 35cP, the image quality was poor. Unevenness in concentration was observed.

Example 2 The layers up to the charge generation layer were coated on the substrate in the same manner as in Example 1.

Furthermore, 7 parts of the same hydrazone compound as in Example 1 and styrene-methyl methacrylate copolymer resin (trade name: MS20
0, Steel Manufacturing Chemical System) was dissolved in toluene. The relationship between the amount of toluene, the viscosity, and the coating speed at which the film thickness is 16 μm is shown in Figure 10. Thus, good results were obtained when the viscosity was 220.150.100 cP, and the value of A was 2400.

When a copy image is taken using the obtained electrophotographic photoreceptor,
Images with a viscosity of 220, 150, and 100 cP were of good quality, but those with a viscosity of 5 [1 cP were highly uneven.

[Brief explanation of drawings]

The figure shows an example of equipment for dip coating. The symbols in the diagram are 1...paint film, 2...liquid tank, 3...
Coating liquid, 4... Cylindrical base with one end closed, 5... Support part, 6... Drive motor (this rotation rotates 7... the lifting screw and lifts up the base), 8... ...Vent pipe, 9... Rubber air chamber (8 and 9 take out part of the air trapped inside the base body). Patent applicant: Canon Co., Ltd., Kyoyoshi Nikai Patent attorney: Yu Kano

Claims (2)

[Claims] (1) In the step of dip coating a solution containing a polymer or copolymer containing styrene or methyl methacrylate and a charge transporting substance, the viscosity of the solution is adjusted to 50 to 300 cP and the coating speed is adjusted. 40crn
1. A method for producing a functionally separated electrophotographic photoreceptor, characterized in that a charge transport layer is formed by coating at a rate of 1/min or less. (2) Viscosity N (cP) and pulling application speed 5 (crn
2. The method for manufacturing a functionally separated electrophotographic photoreceptor according to claim 1, wherein the relationship S=A/N (A is a constant in the range of 500 to 3000).