JPS61235843A - Production of laminate type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent reduction in the sensitivity of an electrophotographic sensitive body, increase in a durable potential change and deterioration in the quality of an image by applying a coating material contg. a charge transferring substance and a binder and having <=600ppm water content to form the charge transferring layer. CONSTITUTION:A coating material for forming a charge transferring layer by application contains a charge transferring substance and a binder and has <=600ppm water content. An amine-base substance is used as the charge transferring substance producing a more significant effect by the controlled water content, and an org. substance having ester groups such as a homo- or copolymer of methyl methacrylate, phenyl methacrylate, silicon methacrylate or isobornyl methacrylate is used as the binder. The charge transferring substance and the binder undergo little chemical change, and a change of the coating material with the lapse of time is controlled, so reduction in the sensitivity of a produced laminate type electrophotographic sensitive body, increase in a durable potential change and deterioration in the quality of an image can be prevented or controlled.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for manufacturing a laminated electrophotographic photoreceptor.

[Conventional technology]

Electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on the type of electrophotographic process to which they are applied. Typical electrophotographic photoreceptors include a photoreceptor in which a photoconductive layer is formed as an image-retaining layer on a support, and a photoreceptor in which a photoconductive layer is laminated as an image-retaining layer and an insulating layer thereon. A) Widely used. A photoreceptor composed of a support and a photoconductive layer is used for image formation by the most common electrophotographic processes, ie, charging, image exposure, development, and, if necessary, transfer.

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are known as photoconductive materials used in electrophotographic photoreceptors. On the other hand, various organic photoconductive polymers such as polyvinylcarbazole t have been proposed, but these polymers are superior to the above-mentioned inorganic photoconductive materials in terms of film formability and light weight. Despite this, it has been difficult to put it into practical use to date because sufficient film formation properties have not yet been achieved, and inorganic photoconductive materials lack sensitivity, durability, and stability against environmental changes. This was because the material was inferior. In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, etc., and U.S. Pat.
Triarylpyrazoline compounds described in JP-A No. 7851, etc., JP-A-51-94828, JP-A-51-9
Low molecular weight organic photoconductors such as the 9-styrylanthracene compound described in Japanese Patent No. 4829 have been proposed. Such low molecular weight organic photoconductors can overcome the drawbacks of film formability that have been a problem in the field of organic photoconductive polymers by appropriately selecting the binder used. , cannot be said to be sufficient in terms of sensitivity.

For this reason, in recent years, a laminated electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed. This electrophotographic photoreceptor is, for example, US Pat. No. 3,837
No. 851, No. 3871882, etc., and it has become possible to improve sensitivity to visible light, charge retention, surface strength, etc.

When manufacturing this type of laminated electrophotographic photoreceptor, over time the photoreceptor paint is stored, especially the charge transport substance, binder, etc. used in the charge transport layer may undergo chemical changes and return to their initial state. It may not show the same sensitivity or durability.

In other words, compared to a new paint solution that has been left at room temperature and humidity for less than one day, a day-old paint solution that has been left at room temperature and humidity for 7 days or more has a lower sensitivity, an increase in durability potential fluctuation, and a lower image quality. This causes inconveniences such as deterioration of quality.

Therefore, the inventors of the present invention have conducted intensive studies on measures to eliminate these disadvantages, and have found that the above-mentioned disadvantages can be overcome by suppressing the water content of the coating for manufacturing photoconductors, especially the coating for coating the charge transport layer. They discovered that this problem could be eliminated and completed the present invention.

[Problems to be solved by the invention]

The present invention has been made in order to solve the above-mentioned problems such as a decrease in the sensitivity of a photoconductor, an increase in fluctuations in durable potential, and a decrease in image quality due to aging of the coating material for manufacturing the photoconductor.

[Means for solving problems]

That is, the method for producing a laminated electrophotographic photoreceptor of the present invention, which was discovered as a means to solve the above problems, produces a laminated electrophotographic photoreceptor having a photosensitive layer with functionally separated charge generation layer and charge transport layer. When producing the charge transport layer, the charge transport layer contains a charge transport material, a binder, and a t component, and has a water content of 600%.
It is characterized in that it is coated using a paint whose concentration is suppressed to ppm or less (hereinafter referred to as the paint for applying a charge transport layer used in the present invention).

[Detailed description and examples of the invention]

The paint for applying the charge transport layer used in the present invention has a high water content!
By suppressing the content to 600 ppm or less, chemical changes in the charge transporting substance and binder are less likely to occur, and by suppressing changes in the paint over time, the resulting laminated electrophotographic photoreceptor is less likely to change. It is possible to eliminate or suppress inconveniences such as increase in durability potential fluctuations and deterioration of image quality.

Particularly, the charge transporting material which can greatly improve the effect of suppressing water content by carrying out the present invention is the amine-based charge transporting material described below.

That is, charge transport substances preferably used in the present invention include pyrene, N-ethylcarbazole, N-isoglobilcarpazole, N-methyl-N-phenylhydrasono-3-methylidene-9-ethylcarbazole, and NlN.
-diphenylhydrasono-3-methylidene-9-ethylcarbazole, N.

N-diphenylhydrazino-3-methylidene-10-etherphenothiazine, N,N-diphenylhydrazino-
3-methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde N-
α-f 7 f Roux N-phenylhydrazone, p-
Pyrrolidinobenzaldehyde-N, N-duphenylhydrazone, 1,3.3-) IJ, 7'tylindolenine-ω-aldehyde-N.

Hydrazones such as N-177enylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1 −
Phenyl-3-(p-diethylaminostyryl)-5-
(p-f ethylaminophenyl)pyrazoline, i-(quinolyl(2), I-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(2))-3- (p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[6-medoxypyridyl (2)
] -3-(p-diethylaminostyryl)-5-(p
-diethylaminophenyl)pyrazoline, i-(pyridyl(3)) -3-(p-diethylaminostyryl)
-5-(p-diethylaminophenyl)pyrazoline, 1
-[Lepidyl (2)) -3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl]pyrazoline, 1-[pyridyl (2)) -3-(p-diethylaminostyryl)-4-methyl-5 -(p-diethylaminophenyl)pyrazoline, 1-[pyridyl (2)
) -3-(α-Methyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)hilazoline, 1-phenyl-3-(p-diethylaminostyryl)
-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazolinato pyrazolines, 2-(p-dimethylaminostyl)-5-diethylaminobenzoxasol, 2-(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)
Oxazole compounds such as -5-(2-/p-phenyl)oxazole, 2-(p-diethylaminosteryl)
-thiazole compounds such as -6-dinithylaminopenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamino -2-
monoarylalkanes such as methylphenyl)hebutane, 1,1゜2.2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine, polyIJ + N-vinylcarbazole , polyvinylpyrene, polyvinylanthracene, polyvinylacridine, Iso9-vinylphenylanthracene, pyrene-formaldehyde 1H! , ethyl carbazole formaldehyde resin, etc.

In addition, examples of the binder preferably used in the present invention include ester group-containing organic substances, particularly methacrylate homopolymers or copolymers such as methyl methacrylate, phenyl methacrylate, silicon methacrylate, and isodernyl methacrylate. It will be done. Furthermore, are these in line with methacrylate resins? Listyrene,
Mention may be made of one or a mixture of two or more of vinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, polytetrafluoroethylene and the like. Examples of the methacrylate copolymer include styrene-methyl methacrylate copolymer and styrene-phenyl methacrylate copolymer.

The charge transport layer is electrically connected to a charge generation layer, which will be described later, and receives and receives charge carriers injected from the charge generation layer in the presence of an electric field.
It has the ability to be transported to the surface. Since this charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Typically it is 5 microns to 30 microns, with a preferred range of 8 microns to 20 microns.

When forming such a charge transport layer, the organic solvent used in the paint for coating the charge transport layer used in the present invention may vary depending on the type of charge transport substance used, or may be used as a substratum for the charge generation layer or underlayer. It is preferable to choose one that does not dissolve the layer. Specific organic solvents include alcohols such as methanol, ethanol, isopro, and p4-ol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-diethylformamide, N,N-dimethylacetamide, and dimethyl. Sulfoxides such as sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters of methyl acetate and ethyl acetate, aliphatic halogenated carbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene, etc. Hydrogens or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

The charge transport layer may be applied using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Mayer-Percoch ink method, a blade coating method, a roller coating method, or a curtain coating method. Can be done. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at a temperature of 30° C. to 200° C. for a period of time ranging from 5 minutes to 2 hours, either stationary or under ventilation.

The charge generating layer used in the present invention includes selenium, selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine pigments, andanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, and disazo pigments (monoazo, disazo, and trisazo). , azo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanines, quinocyanines, or a separate vapor deposited layer or resin dispersion layer selected from charge generating materials such as amorphous silicon described in JP-A-54-143645. can.

Such a charge transport layer and a charge generation layer are provided on a support with an undercoat layer interposed therebetween, if necessary.

Although the layer order of the charge transport layer and the charge generation layer can be selected arbitrarily, it is preferable to provide the charge generation layer on the side closer to the support.

As the support used in the present invention, metals such as aluminum and stainless steel, cylindrical shapes, cylinders, or films made of paper, plastic, etc. are used.

The undercoat layer is formed to improve adhesion of the photosensitive layer, improve coating properties, protect the substrate, cover defects on the substrate, improve charge injection from the substrate, protect the photosensitive layer from electrical breakdown, etc. . What is the material for the undercoat layer? Rivinyl alcohol, poly-N-vinylimidazole, I-lyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, copolymerized nylon, glue, gelatin, and the like are known. These are each dissolved in a suitable solvent and applied onto the substrate.

The film thickness is about 0.2 to 2μ.

Next, in order to explain the action and effect of setting the water content to 600 ppm or less in the paint for applying the charge transport layer used in the present invention, an amine charge transport substance is used as the charge transport substance, and methacrylate is used as the binder. The mechanism of these chemical changes caused by moisture when using a resin based resin will be explained.

(I) First, the water contained in the solvent, and the water absorbed into the paint from the air over time, hydrolyzes the ester groups of the methacrylate resin, resulting in the formation of carboxylic acid groups. bring about

For example, O.Furthermore, this effect acts as a catalyst when the paint catalyzes the metal (metal support used in electrophotographic photoreceptors, metal used in equipment for applying the paint).

(n) The protons of the generated carboxylic acid attack the charge transport substance and lower the electron density of the charge transport substance. Since the charge transport material is an electron donating material, a decrease in electron density will impede carrier transportability.

For example, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone The paint for coating the charge transport layer used in the present invention has a water content of 600 p.
pm or less, preferably 100 ppm or less. Water content is 600ppmy! - In most cases, a gradual deterioration of the properties is observed from around the second day of preparation. Specific means for suppressing the water content include a method of bringing a dehydrating agent, desiccant, etc. into contact with the paint.

Examples of the dehydrating agent and desiccant include activated alumina, silica gel, molecular sieve, zeolite, magnesium oxide, calcium chloride, calcium oxide, anhydrous zinc chloride, anhydrosdehydrite, anhydrous sulfuric steel, sulfuric acid,
etc., but as a matter of course, those that react with charge transport substances and binders cannot be used.

The experimental results showed that molecular sieves and silica gel had no adverse effects, and molecular sieves were particularly effective.

The present invention 8A will be explained in detail below using examples.

Example 1 An ammonia aqueous solution of casein (casein 11.2.9, 281 ammonia water III, water 222 mj) was applied by dip coating onto a mirror-finished cylindrical aluminum cylinder, so that the film thickness after drying was 1.0 microns. It was applied and dried.

Next, the sosazo pigment 5I of the structural formula was added to 95m ethanol of a butyral resin (degree of butyralization 63 mol%) 21IyL? It was added to the dissolved liquid and dispersed for 2 hours using an attritor. This dispersion is applied to the previously formed casein layer with a film thickness of O,
The coating was applied by dip coating to a thickness of S micron and dried to form a charge generation layer.

Next, a hydrazone compound having the structural formula: as a charge transport layer and a methyl methacrylate resin (Dyanal BR-85: Mitsubishi Rayon Co., Ltd.) as a binder were used as a charge transport layer.
A 20% solution of monochlorbencef (manufactured by M.D.) was mixed in a weight ratio of 1=1, and the solution was applied by dip coating onto the charge generation layer in the manner described below so that the film thickness after drying was 16 μm. .

Sample ■: Applied on the same day it was prepared.

Sample ① After being placed in a glass container and sealed, it was aged for 15 days in an atmosphere of 60°C.

Sample ① After being placed in a stainless steel container and sealed, it was aged for 15 days in an atmosphere of 60°C.

Sample ① Same as ②, but molecular sieve (grade 4A) was added to the liquid in an amount of 20% by weight of the liquid weight.

Sample ① Same as ②, but molecular sieve (grade 4A) was added to the liquid in an amount of 20% by weight of the liquid weight.

In order to measure the charging characteristics of the photoconductor prepared in this way and the fluctuations in bright and dark potential when used repeatedly, the photoconductor t-5,6kVo was prepared in this example: It was installed in an electrophotographic copying machine equipped with an Irona charger, an exposure optical system with an exposure amount of 151 ux-aec, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as a cylinder is driven.

Using this copying machine, the initial oeprm potential (VL), dark potential (VD), and light potential (■'L) and dark potential (v'D) after 2000 uses were measured.

The potential characteristics of each sample were as follows.

Initial After 2000 cycles vD vL vD vL test sample-5
80V -80V -600V -100V sample -580V -90V -610V -120
V sample -570V -120V -620V
-180V sample -580V -80V -60
0V -100V sample -580V -90V
-600V -110V The water content at this time was measured by the Karl Fischer method, and the water content of each paint was as follows.

Sample 0860ppm Sample 0840ppm Sample 0840ppm Sample 0380ppm Sample 0380ppm These results show that by adding molecular sheep to the paint and storing it, the water content decreases, the liquid does not change over time, and the potential characteristics at the initial stage of formulation can be maintained. I know it will be maintained.

Example 2 Coatings for the charge generation layer and the charge transport layer were prepared in the same manner as in Example 1. The paint for applying the charge transport layer was applied by dip coating onto the charge generation layer in the manner described below so that the film thickness after drying was 16 μm.

Sample ■: Applied on the same day it was prepared.

Sample ① The sample was placed in a stainless steel container with a circulation system and allowed to age for 15 days at room temperature and humidity.

Add 20 weight of silica glue to the same thread as sample ■ ■.
I put it in.

Moisture content is 0900 ppm for sample, 0900 ppm for sample
.

Sample 1: 600 ppm.

The photosensitive drum thus prepared was attached to an actual copying material, and 1000 consecutive images were sampled. As a result of image evaluation, samples ■ and ■ were 1000 from the beginning.
I was able to obtain clear images with sufficient contrast and no capri until the end of the image. However, in sample (3), capri occurred in the initial stage, and the contrast further deteriorated after continuous paper passing.

〔Effect of the invention〕

According to the present invention, deterioration of characteristics due to aging of the paint for applying the charge transport layer is suppressed, and a laminated electrophotographic photoreceptor is produced that does not cause disadvantages such as a decrease in sensitivity, an increase in durable potential fluctuation, and a decrease in image quality. It can always be manufactured stably.

Claims (4)

[Claims] (1) When manufacturing a laminated electrophotographic photoreceptor having a photosensitive layer functionally separated into a charge generation layer and a charge transport layer, the charge transport layer contains a charge transport substance and a binder as components; A method for manufacturing a laminated electrophotographic photoreceptor, characterized in that coating is performed using a paint whose water content is suppressed to 600 ppm or less. (2) The method for producing a laminated electrophotographic photoreceptor according to claim (1), wherein the charge transport material is an amine charge transport material. (3) The method for producing a laminated electrophotographic photoreceptor according to claim 1 or (2), wherein the binder contains an ester group-containing organic substance as a component. (4) The method for producing a laminated electrophotographic photoreceptor according to claim (3), wherein the ester group-containing organic substance is a methacrylate resin.