JPS63101853A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To reduce rise of residual potential due to repeated uses and variance of sensitivity by forming an underlayer composed essentially of an alcohol- soluble nylon containing a water-soluble nylon. CONSTITUTION:The underlayer 2 and a photosensitive layer 3 comprising an electric charge generating layer 31 and a charge transfer layer 32 are successively laminated on a conductive substrate 1. The layer 2 is formed by coating with a coating material composed essentially of the alcohol-soluble nylon containing the water-soluble nylon, thus permitting the obtained photosensitive body to be small in rise of residual potential due to repeated uses and variance of sensitivity and to retain always good sensitivity.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an electrophotographic photoreceptor, and more particularly, to an undercoat layer and This invention relates to improvements in charge generation layers.

[Prior Art] In general, electrophotographic photoreceptors that are used repeatedly are required to obtain good charging properties (to prevent unnecessary charge injection and maintain appropriate charge acceptance), and furthermore, In order to improve the adhesion of the photosensitive layer to the support, an undercoat layer made of a resin having relatively low resistance is provided between the support and the photosensitive layer.

On the other hand, the photosensitive layer in an electrophotographic photoreceptor consists of a single layer type such as Se-based or TNF, and a charge generation layer (
A so-called functionally separated type of stacked layer consisting of a CGL) and a charge transfer layer (CTL) is known. Each of these electrophotographic photoreceptors has advantages and disadvantages, but
It can be said that the latter laminated electrophotographic photoreceptor is superior in terms of a wide range of material selection.

Conventional laminated electrophotographic photoreceptors (hereinafter sometimes simply referred to as "laminated photoreceptors") tend to have a residual potential that increases with repeated use, resulting in a decrease in sensitivity. It recognized.

As a means to eliminate these inconveniences, polyamide resin is used for the undercoat layer of the laminated photoreceptor, and polyvinyl butyral resin is used as the binder for CGL (Japanese Patent Laid-Open No. 58-3
0757), alcohol-soluble nylon is used for the undercoat layer, and polyvinyl resin and formal resin are used as the binder for CGL (Japanese Patent Application Laid-Open No. 60-202448).
(described in Japanese Patent Application Laid-Open No. 60-196766), using alcohol-soluble nylon as an undercoat layer and using phenoxy resin as a binder for CGL (described in JP-A-60-196766), but none of them have been proposed. The reality is that the increase in residual potential cannot be suppressed to the extent that the inventors intended.

[Objective] The present invention provides a laminated electrophotographic photoreceptor that exhibits very little increase in residual potential or change in sensitivity during repeated use, and that always maintains good sensitivity with little change in sensitivity.

[Structure] The present invention provides an electrophotographic photoreceptor in which an undercoat layer, a charge generation layer, and a charge transfer layer are sequentially laminated on a conductive support, in which the undercoat layer is mainly made of alcohol-soluble nylon to which water-soluble nylon is added. It is characterized by being an ingredient.

Incidentally, the present inventors have found that by using alcohol-soluble nylon obtained by adding water-soluble nylon to the undercoating resin, a laminated electrophotographic photoreceptor can be obtained that can significantly improve residual potential and sensitivity changes during repeated use. I made sure of that. The present invention was completed based on such knowledge.

The present invention will be explained in more detail below with reference to the accompanying drawings. As mentioned above, the photoreceptor of the present invention has a structure in which an undercoat layer 2 and a photosensitive layer 3 are sequentially laminated on a conductive support 1. It is taken. The photosensitive M33 is composed of a CGL31 and a CTL32.

The conductive support 1 may be made of aluminum, nickel, stainless steel, chromium, nichrome, copper, etc.; plastic in which conductive pigments such as carbon are dispersed; or insulating support (
(such as plastic or plastic film)
Examples include those on which metal, tin oxide, indium oxide, etc. are vapor-deposited, or coated with conductive paint.

The undercoat 312 is mainly made of alcohol-soluble nylon with water-soluble nylon added, but PVA
, casein, etc. may be added as long as it is a small amount. However, alcohol-soluble nylon to which water-soluble nylon is added accounts for at least 80% by weight of the entire undercoat layer 2.
It is necessary to occupy more than If the ratio is below this, the increase in residual potential during repeated use can be suppressed,
It becomes difficult to improve sensitivity changes.

Water-soluble nylon is a modified polyamide imparted with the ability to dissolve in water, and is commercially available as AQ Nylon (Toshisha II), for example, and is easily available.

On the other hand, the alcohol-soluble nylon is preferably linear polyamide, and so-called nylon, copolymerized nylon, N-methoxymethylated nylon, etc. are used. These are also commercially available as, for example, CM8000 (manufactured by Toshisha Co., Ltd.).

In the alcohol-soluble nylon to which such water-soluble nylon is added, the amount of the former water-soluble nylon is suitably 1 to 20% by weight, preferably 3 to 10% by weight, based on the latter alcohol-soluble nylon. If alcohol-soluble nylon containing nylon added outside this range is used, it will be difficult to achieve the object of the present invention.

The thickness of the undercoat layer 2 is preferably 0.1 to 5 μm, particularly preferably 0.3 to 2 μm. If the film thickness is too thin, abnormal images will occur due to the effects of minute defects, dirt, deposits, scratches, etc. on the surface of the support 1, and if the film thickness is too thick, the residual potential will increase. Scratches appear on the copy.

The undercoat layer 2 is made by dissolving water-soluble nylon and alcohol-soluble nylon to an appropriate viscosity in a mixed solvent of water and alcohols (methanol, ethanol, isopropanol), dioxane, ethylene glycol, etc. This can be applied using a wire blade, air knife, dipping method, etc.

The charge generation layer 31 may be formed only from a charge generation substance, or may be formed by uniformly dispersing the charge generation substance in a binder.

Therefore, the charge generating material 31 is able to absorb these components into the undercoat layer 2.
The undercoat layer 2 is dispersed in a suitable solvent that does not dissolve the undercoat layer 2, and is coated on the undercoat layer 2 according to a known method, followed by drying.

Examples of charge-generating substances include CI Pigment Blue 25 (curler index (CI) 2118), CI Pigment Red 41 (CI 21200),
In addition to C.I. Acid Red 52 (CI 45100) and C.I. Basic Red S (CI 45210), azo pigments with a carbazole skeleton (JP-A-5
3-95033), azo pigments having a styrylstilbene skeleton (described in JP-A-53-138229), azo pigments having a triphenylamine skeleton (described in JP-A-53-138229),
(described in JP-A-53-132547), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-2172)
8), an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-12742), an azo pigment having a fluorenone skeleton (described in JP-A-54-22834)
Azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-17733),
2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-17734), trisazo pigments having a carbazole skeleton (described in JP-A-57-195767, JP-A-57-195768) ), etc., as well as C.I. Pigment Blue 16
Phthalocyanine pigments such as (CI 74100), indigo pigments such as C.I. Butt Brown 5 (CI73410) and C.I. Butt Dye (CI 73030), perylene pigments such as Argo Scarlet B and Indanthrene Scarlet R (manufactured by Bayer). , square link pigment, etc.; inorganic pigments such as Ss, Se alloy, CdS, amorphous Si, etc. can be used.

Binder resins include polyamide, polyurethane,
Polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, etc. are used.

The appropriate amount of the binder resin is 5 to 100 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the charge generating material.

Also, the solvents used here are tetrahydrofuran, cyclohexanone, and dioxane.

Diglolethane and the like are preferred.

The thickness of the charge generation layer 31 is 0.01 to 2μ, preferably 0.
．． It is about 1 to 1 μm.

The charge transfer layer (CTL) 32 is prepared by dissolving a charge transfer substance, a binder, and if necessary, a plasticizer and a leveling agent in a suitable solvent, and coating the solution on the charge generation layer 31 according to various known coating methods. Formed by drying.

Charge transfer substances include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, and oxadiazole derivatives. , imidazole derivatives, 9-(p-diethylaminostyryl)anthracene, 1,1-bis(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-stilbene derivatives, and other electron-donating substances can be mentioned.

As a binder, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyester Vinyl chloride, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral 1. Examples include thermoplastic or thermosetting resins such as polyvinylformer, polyvinyltoluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

Solvents for forming CTL32 include tetrahydrofuran, dioxane, toluene, monochlorobenzene,
Dichloroethane, methylene chloride, etc. are used. In addition,
The thickness of the charge transfer layer 32 is 5 to 100 μm, preferably 5 to 100 μm.
It is about 30 μm.

The thus produced photoreceptor of the present invention is suitable for repeated use, and if necessary, a protective layer similar to conventional ones can be provided on the surface of the photosensitive layer.

Next, examples and comparative examples will be shown.

Example 1 Alcohol-soluble nylon (CM8000, manufactured by Toshisha Co., Ltd.) was placed on an aluminum plate (J-K51070, Sumitomo Light Metal Company 1'!!!5) approximately 0.2 mm thick.
6.4g water-soluble nylon (A-90, Toshisha 11)
0.7g water
55.9g methanol
A mixed solution of 14.7 g was applied by dip coating and dried to form an undercoat layer with a thickness of about 1 μm.

On the other hand, a mixture consisting of the following composition was placed in a ball mill pot, and a 10 mmφ SUS ball was used as a mill member.
After ball milling for 48 hours, 20 g of cyclohexanone was further added and milling was carried out for 1 hour.

Cyclohexanone 19g
After milling, take out the mill base and check that the solid content concentration is 1.
Add cyclohexanone to dilute to % by weight,
A dispersion liquid for forming a charge generation layer was prepared by stirring.

This charge generation layer forming liquid was applied onto the undercoat layer by dip coating to form a charge generation layer having a thickness of about 0.2 μm after drying.

Subsequently, a charge transfer layer forming liquid having the following composition was applied to i! Made by ii,
Dip coating on the charge generation layer, thickness after drying is approximately 22μm
A laminated electrophotographic photoreceptor consisting of a conductive support, an undercoat layer, a charge generation layer, and a charge transfer layer was prepared.

(Hydrazone compound) Polycarbonate resin (C-1400, manufactured by Kijin Kasei Co., Ltd.)
10g silicone oil (KF 50, manufactured by Shin-Etsu Chemical) 0.002g methylene chloride
76g Example 2 Water-soluble nylon in the undercoat layer forming wave of Example 1 was
-70 (manufactured by Toshisha Co., Ltd.), a subbing layer with a thickness of approximately 1 μm was formed, and 50 g of charge generation layer forming liquid having the following composition Example 1
A charge generation layer forming solution consisting of the following is dip coated onto the undercoat layer,
It was dried to form a charge generation layer with a thickness of about 0.15 μm.

Subsequently, a charge transfer layer forming liquid having the following composition was prepared, applied by dip coating onto the charge generation layer, and dried to form a charge transfer layer with a thickness of about 22 μm. A laminated electrophotographic photoreceptor consisting of a charge transfer layer was prepared.

1.1-Bis(4-dibenzylaminophenyl)propane 9g Polycarbonate resin (C-1400, manufactured by Kijin Kasei Co., Ltd.) 10g Silicone oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002g Methylene chloride
76 g Example 3 A laminated electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1 except that a trisazo pigment having the following structural formula was used instead of the bisazo pigment as a charge generating substance.

(Left below) Comparative Example 1 Water-soluble nylon (A-9
A comparative laminated electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1, except that the sample No. 0 (manufactured by Toshisha) was removed.

These samples (3 types of photoreceptors of the present invention, 1 type of comparative photoreceptor)
The electrophotographic photoreceptor was tested using an electrostatic copying tester (SP428 type,
(manufactured by Kawaguchi Electric Seisakusho Co., Ltd.), and the electrophotographic characteristics were evaluated under the following conditions (measured in dynamic mode).

First, a -6 KV corona discharge was performed for 20 seconds to charge the photoreceptor. Surface potential VZ (volts) after 2 seconds of charging, 2
Measure the surface potential V m (volts) after 0 seconds, and then
The surface potential VO (volt) was measured after being left in the dark for 0 seconds. Next, when the surface potential of the photoreceptor reached 800V, 4
．． Irradiated with 5 lux tungsten light, the surface potential was 1
The exposure amount Ei attenuates to 710, . (Qux·sec) and surface potential V after 30 seconds of irradiation. (volts) was measured and used as the initial characteristics.

Furthermore, the sample was transferred to a dedicated fatigue testing machine and subjected to -6KV corona discharge and 50 Lux light irradiation 40 times/min, approximately 5
After repeating 000 times, the sample was immediately transferred to the electrostatic copying paper tester described above, and V zt Vllt Vo+E1,1°9V3° was measured under the same conditions as those used to measure the initial characteristics, and this was taken as the fatigue property. The results of these measurements are shown in Table-1.

(The following is a blank space) Table 1 [Effects] As is clear from the examples, the electrophotographic photoreceptor of the present invention exhibits excellent electrophotographic properties even after repeated use, and in addition, there is little change in properties due to fatigue.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a typical example of a laminated electrophotographic photoreceptor according to the present invention.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor in which an undercoat layer, a charge generation layer, and a charge transfer layer are sequentially laminated on a conductive support, the undercoat layer is mainly composed of alcohol-soluble nylon to which water-soluble nylon is added. Characteristic electrophotographic photoreceptor.