JPS62242954A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having improved sensitivity and uniformity of picture image by incorporating a specific polysulfone as a binder of an electrostatic charge generating layer. CONSTITUTION:The titled body is formed by laminating an electrostatic charge generating layer 13 and an electrostatic charge transfer layer 15 on a conductive substrate body 11 in this order. The layer 13 is composed of the layer which is uniformly dispersed the electrostatic charge generating substance such as azo pigment, etc., in the polysulfone shown by formula I or II. Thus, the laminated type photosensitive body having excellent sensitivity and uniformity of picture image and less tendency for increasing residual potential, even if in case of a repetitive use of the titled body, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called functionally separated electrophotographic photoreceptor in which a charge generation layer and a charge transfer layer are provided on a conductive support.

There are many functionally separated laminated electrophotographic photoreceptors that have a charge generation layer that generates charge carriers through light absorption and a charge transfer layer that moves the generated charge carriers using an electric field on a conductive support. Proposed.

This is because many charge-generating substances that generate charge carriers do not have film-forming properties by themselves.

A binder is required to form a charge generation layer using such a charge generation substance.

In order to efficiently absorb light and efficiently inject the generated charge carriers into the charge transfer layer, the charge generation layer has a relatively large amount of charge generation substance present in the layer and a thickness of the layer. It is preferable for the resin binder in the charge generation layer to be thin.

It is required that the charge generating substance be dispersed in a large amount. In addition, the charge-generating substance must be uniformly dispersed in the layer, and if this dispersion is uneven, the uniformity of the image will deteriorate.Furthermore, in the electrophotographic process, the photosensitivity is high. In particular, it is important that the residual potential be low, and from this point of view as well, the selection of the resin binder in the charge generation layer is extremely important.

As the resin binder used in the charge generation layer, polyester resin is used in combination with an azo pigment (
JP-A No. 54-22834, etc.).

In addition, hydroxypropyl cellulose resin (Japanese Unexamined Patent Publication No. 5
7-169754), fatty acid cellulose ester resin (Japanese Unexamined Patent Publication No. 58-166353), acrylic resin (Japanese Unexamined Patent Publication No. 58-192040), and polyvinyl butyral resin (especially JP-A-58-30757), linear polyester resin (JP-A-58-9) in combination with a copolymerized polyamide subbing layer
3739), phenoxy resin, polyvinyl formal resin or ethyl cellulose resin (JP-A-60-19676) in combination with an alcohol-soluble nylon subbing layer.
Publication No. 6, Publication No. 60-202448, Publication No. 60-20
No. 2449), etc. have been reported.

However, when these resin binders are used in the charge generation layer, the sensitivity, residual potential, and image uniformity are still unsatisfactory, and further improvements are needed.

The present invention provides a laminated type electrophotographic photoreceptor that has excellent sensitivity and image uniformity and exhibits a small increase in residual potential even after repeated use.

Sentence No. 31411 The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which a charge generation layer containing a charge generation substance and a resin binder and a charge transport layer are provided on an electrically conductive support, wherein the charge generation layer contains a charge generation layer containing a charge generation material and a resin binder. It is characterized by using a polysulfone resin represented by the following general formula (I) or general formula (n).

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a sectional view illustrating the layer structure of the electrophotographic photoreceptor of the present invention. A charge generation layer 1 is provided on the conductive support 11.
3 and a charge transfer layer 15 are sequentially laminated. The charge generation layer 13 is formed by uniformly dispersing a charge generation substance in a resin binder.

As the resin binder, a polysulfone resin represented by the above general formula (I) or general formula (If) is used.

Examples of the charge generating substance include CI Pigment Blue 25 [Color Index (CI) 211803,
CI Pigment Red 41 (CI 21200),
C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton,
Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A No. 53-95033), azo pigments with a styrylstilbene skeleton (described in JP-A-53-138229), triphenylamine Azo pigments having a skeleton (Japanese Patent Application Laid-Open No. 53-132
547), an azo pigment having a dibenzothiophene skeleton (described in JP-A No. 54-21728 a),
Azo pigments having an oxadiazole skeleton
12742), an azo pigment having a fluorenone skeleton (described in JP-A No. 54-22834), an azo pigment having a bisstilbene skeleton (described in JP-A-54-17)
733), azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2129),
(described in JP-A No. 54-17734), trisazo pigments having a carbazole skeleton (described in JP-A-57-19576)
Publication No. 7.

57-195768), phthalocyanine pigments such as CI Pigment Blue 16 (CI 74100), CI Bat Brown 5 (CI
73410), CI 7303
Organic pigments such as indigo pigments such as 0), perylene pigments such as Argo Scarlet B (manufactured by Violet) and Indance Scarlet R (manufactured by Bayer), Se, S
Inorganic pigments such as e-alloy, CdS, amorphous Si, etc. can be used.

Among these charge-generating substances, organic pigments, particularly azo pigments, are preferred. Furthermore, among azo pigments, the following general formula (I
The trisazo pigment shown in II) or the general formula (IV)
A combination of the disazo pigment represented by and the resin binder of the present invention is preferred.

(Left below) N=N-A' (In the formula, A1 is, where X, Ar1. Ar'', R', R
” is as follows.

X: An aromatic ring such as a benzene ring or a naphthalene ring, or a hetero ring such as an indole ring, a carbazole ring, or a benzofuran ring, or a substituted product of Sowara, Ar': An aromatic ring such as a benzene ring or a naphthalene ring, or dibenzofuran A heterocyclic ring such as a ring or a substituted product thereof, A r ”: an aromatic ring such as a benzene ring or a naphthalene ring, or a substituted product thereof, R1: hydrogen, a lower alkyl group or a phenyl group, or a substituted product thereof, R2: lower alkyl group, phenyl group, carboxyl group or ester thereof), A2 is, where X, A rl, A S, A r'
pR1, R'', R' are as follows.

X: Aromatic rings such as benzene rings and naphthalene rings, or heterocycles such as indole rings, carbazole rings, and benzofuran rings, or substituted products thereof, A r 1p A r 3: Aromatic rings such as benzene rings and naphthalene rings ring, or a petero ring such as a dibenzofuran ring, or a substituent thereof; Ar": an aromatic ring such as a benzene ring or a naphthalene ring, or a substituent thereof; R', R': hydrogen, a lower alkyl group or a phenyl group, or a substituent thereof; (substituted product, R2=lower alkyl group, phenyl group, carboxyl group or ester thereof) Specific examples of these trisazo pigments and disazo pigments are shown in Tables 1 and 2 below.

(Below the margin) Table 1 Trisazo compound of general formula (m) (below the margin) Pigment blood 1 Face blood 1 (below the margin) tmk' (below the margin) Pigment practice 1 Pigment practice A1: C'ard margin) Kink (Left below) Pigment Point 2 Pigment Blood 2 Face Transfer 2 The binder resin is suitably used in an amount of 5 to 100 parts by weight per 100 parts by weight of the charge generating substance.

Preferably it is 10 to 50 parts by weight.

The thickness of the charge generation layer 13 is suitably about 0.05 to 1 .mu.m, preferably 0.1 to 0.5 .mu.m.

The charge-generating Ji513 can be formed by dissolving or dispersing a binder and a charge-generating substance in a suitable solvent, applying the solution, and drying the solution. As a solvent, benzene, toluene, xylene, methylene chloride, dichloroethane, monochlorobenzene, dichlorobenzene, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, cyclohexanone, methyl cellosolve, ethyl cellosolve, etc. can be used alone or in combination. can.

The charge transfer layer 15 is prepared by dissolving or dispersing a charge transfer substance and a binder in a suitable solvent, and then adding the charge transfer material and the binder to the charge generation layer 13.
It can be formed by coating it on top and drying it. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

As the charge transfer substance, poly-N-vinylcarbazole and its derivatives, poly-rubazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole Derivatives, imidazole derivatives, triphenylamine derivatives, 9-(p-diethylaminostyryl)anthracene, 1,1-bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenyl Examples include electron-donating substances such as stilbene derivatives.

As the binder, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate.

Polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenolic resin.

Examples include thermoplastic or thermosetting resins such as alkyred resins.

As the solvent at this time, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. can be used.

The thickness of the charge transfer layer 15 is suitably about 5 to 100 μI.6 The conductive support 11 may be made of aluminum, nickel, chromium, nichrome, steel, tin oxide, indium oxide, etc. deposited on a plastic film, or aluminum. , nickel, stainless steel, etc. plates and their adhesives, 1. ．． 1
．． 1. It is possible to use pipes that have been made into blank pipes by methods such as , extrusion, and drawing, and then surface-treated by cutting, superfinishing, polishing, and the like.

FIG. 2 is a sectional view showing another example of the structure of the electrophotographic photoreceptor of the present invention, except that an undercoat layer 17 is provided between the conductive support 11 and the charge generation layer 13. It is similar to that in FIG. The undercoat layer 17 improves chargeability, adhesion, and surface properties of the substrate.For example, ZnO is used in the resin undercoat layer.

By dispersing a pigment having a higher refractive index than the resin forming the subbing layer, such as TiO2 or ZnS, the function of preventing moiré can be achieved. Examples of this resin include the copolyamides already mentioned, alcohol-soluble nylon, polyvinyl butyral (Japanese Patent Application Laid-open No. 59-36258), and water-soluble polyvinyl butyral (Japanese Patent Application Laid-open Nos. 60-232553 and 60-232554). etc. can be used.

Among these, durability can be particularly improved when a subbing layer containing alcohol-soluble nylon as a main component and a charge generation layer of the present invention are used in combination.

Alcohol-soluble nylon resins include nylon 6,
Nylon 66, nylon 610. Copolymerized nylons such as nylon 11 and nylon 12, so-called copolymerized nylons such as nylon 6766/bis(4-7minocyclohexyl)methane-6 copolymer, and homonylons such as N-alkoxymethyl modified nylons. Examples include those that have been denatured. These alcohol-soluble nylon resins are soluble only in limited solvents such as lower aliphatic alcohols such as methanol, ethanol, and propatool, tetrahydrofuryl alcohol, and dimethylformamide.

Therefore, when forming an undercoat layer and then forming a charge generation layer thereon.

As the solvent for coating the charge generation layer, solvents other than those mentioned above may be used, and the selectivity of the solvent can be expanded.

The thickness of the undercoat layer is suitably about 0.01 to 10 .mu.m, preferably 0.01 to 5 .mu.I.

214υ碩1 According to the present invention, as the binder resin of the charge generation layer,
By using a polysulfone resin, it is possible to realize an electrophotographic photoreceptor with high sensitivity and excellent image uniformity, and which exhibits little increase in residual potential even after repeated use.

Examples 1 to 8 5 parts by weight of the trisazo pigment or disazo pigment shown in Table 3 below (specified in terms of pigments in Table 1 or 2 above) and 160 parts by weight of a 1.25% by weight cyclohexanone solution of resin binder. was processed in a ball mill for 72 hours to prepare a pigment dispersion.

Next, 350 parts by weight of cyclohexanone was added and mixed with 100 parts by weight of this pigment dispersion while stirring to prepare a coating liquid for a charge generation layer.

On a 75 μm polyester substrate on which A1 was vacuum-deposited,
The above coating solution for a charge generation layer was coated with a blade after providing an undercoat layer or directly, and cured by heating at 130° C. for 10 minutes to form a charge generation layer of about 0.1 μm. When providing a subbing layer, use alcohol-soluble nylon resin (trade name: CM
-8000. 1 wt% methanol solution (manufactured by Toshi ■),
Blade coating on the above polyester film substrate,
It was heated at 100° C. for 10 minutes to form a subbing layer of about 0.3 μm.

Next, a charge transfer layer coating solution having the following composition was coated on the charge generation layer with a blade, heated at 130° C. for 30 minutes, and dried to form a charge transfer layer with a thickness of about 20 μm.

Coating liquid for charge diameter layer 553 parts by weight of α-phenylstilbene compound with the following structural formula 614 parts by weight of polycarbonate (product name, Panlite C1400, Teijin Noh) Silicone oil 1 part by weight (product name, KF50, manufactured by Shin-Etsu Silicone) ) methylene chloride
4800 parts by weight Comparative Examples 1 and 2 Except for replacing the polysulfone resin in the charge generation layer coating solution with polyvinyl butyral resin (trade name, XYHL: manufactured by Union Carbide Plastics Company).
An electrophotographic photoreceptor was obtained in the same manner as in the above example.

The electrophotographic photoreceptor produced as described above was evaluated for electrophotographic characteristics as follows (measured in dynamic mode) using an electrostatic copying paper tester (Kawaguchi Electric Seisakusho ■, model SP 428). first.

Each photoreceptor was charged with a corona discharge of 16 KV for 20 seconds, and then the surface potential V, (volt) was measured when it was left in a dark place for 20 seconds.
When it becomes volt, irradiate tungsten light and -8
The exposure amount required to attenuate to 0 volts is 5 (Iux-3
ec) was calculated.

The above results are summarized in Table 4.

Furthermore, when these electrophotographic photoreceptors were pasted on an 80m+aφ aluminum drum and the images were evaluated using an FT4060 (■Ricoh copier), sharp and uniform images were obtained with the photoreceptors of Examples 1 to 8. On the other hand, in the photoreceptors of Comparative Examples 1 and 2, images in halftone areas were rough, and background stains in solid white areas were noticeable. here,
FT4060 is used by modifying the charging and transfer charger and developing bias power supplies to negative polarity, and the developer is FT80.
30 (-Ricoh copier) was used.

Further, after the evaluation of one image was completed, the developing section was removed and the electrostatic characteristics were repeatedly evaluated in the electrostatic repetition mode. Third
As shown in the figure, compared to Comparative Example 2, the photoreceptor of Example 2 had less fluctuation in potential (VR) after static elimination, and so, o
It can be seen that it can withstand 00 copies. The photoreceptors of other examples also exhibited residual potential characteristics that could withstand so many copies.

(Margin below)

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views schematically showing an example of the structure of an electrophotographic photoreceptor of the present invention. FIG. 3 is a graph showing 5 charging characteristics and residual potential characteristics.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor in which a charge generation layer containing a charge generation substance and a resin binder and a charge transfer layer are provided on a conductive support, the resin binder of the charge generation layer may include the following: General formula (I) or general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) An electronic device characterized by using a polysulfone resin shown in Photographic photoreceptor.