JPS604945A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form a surface protective layer which does not get cloudy and has satisfactory hardness only by drying after a conventional coating stage by adding a specified amount of an organotin compound to a coating liq. for forming a surface protective layer. CONSTITUTION:A surface protective layer contg. an electric resistance regulator, a thermosetting resin and 0.01-10wt% organotin compound basing on the amount of the thermosetting resin is formed on an org. photoconductive layer contg. an org. photoconductor such as a dispersible photoconductor or a separated function type photoconductor. Polyurethane resin, thermosetting acrylic resin, silicone resin or the like is used as the thermosetting resin. Stannous octoate, dibutyltin-2-ethyl hexoate, triethyltin acetate or the like is used as the organotin compound. The electric resistance regulator is a metal or a metallic oxide with <=10<9>OMEGA.cm resistivity, and the preferred regulator is a solid soln. of tin oxide or titanium oxide having <=0.3mum average particle size or a mixture of two kinds of such solid solns. The regulator is contained in the protective layer by 10- 50wt%. Drying is carried out at 100-140 deg.C for 3-5min after coating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor having a surface protective layer provided on an organic photoconductor layer.

BACKGROUND ART In an electrophotographic method conventionally known as the Carlson method, a large number of copies are made by repeating the processes of charging, exposing, developing, transferring, and cleaning. Therefore, the surface of the electrophotographic photoreceptor is constantly subjected to mechanical, electrical, and chemical stress.

For this reason, in order to prevent damage to the photoreceptor and extend its life, a protective layer is provided to improve the mechanical strength of the surface.

In the Carlson method, the electrical resistance is 109 to 1 as a protective layer.
A low resistance protective layer having a resistance of 0.014Ω·α is used. This protective layer is formed by applying a coating liquid containing a resistance adjuster to a thermoplastic resin or thermosetting resin as a resin component. When a thermosetting resin is used as the resin component, a protective layer with high surface hardness is formed, but when a thermosetting resin is applied onto an organic photoconductor layer, the surface of the protective layer becomes cloudy. be.

If clouding occurs on the surface of the protective layer, undesirable phenomena such as a decrease in sensitivity, a decrease in resolution, and fog on copies occur when the photoconductor is used as an electrophotographic photoreceptor. In addition, since a curing process is required at high temperatures for a long period of time, work efficiency may be poor (or the organic photosensitive material in the photosensitive layer may decompose and the photosensitive characteristics may be impaired, or the notebook photoreceptor may become blocked). There are drawbacks such as:

OBJECTS OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that has a long life and is suitable for the Carlson process.

A further object of the present invention is to provide a photoreceptor having a protective layer made of a thermosetting resin that does not cause clouding on the surface. An object of the present invention is to provide a photoreceptor that does not require curing treatment and has excellent surface mechanical strength.

Structure of the Invention In view of the above-mentioned object, the inventor of the present invention has made extensive studies and found that when applying a surface protective layer, by incorporating an organic tin compound into the coating liquid, a normal coating process can be performed without the need for a special curing treatment process. Based on this finding, the present invention was completed based on the finding that a surface protective layer with sufficient hardness can be provided without clouding the surface by drying the O used in the photoreceptor of the present invention. Examples of organic photoconductors include carbazole-based vinyl polymers, polymers such as condensates of pyrene and formaldehyde, charge transfer type complexes consisting of donor polymers/acceptor polymers such as PvK/TNF,
7 Dispersed photoconductor in which talocyanine-based, indigo-based, perylene-based, azo-based pigments, etc. are dispersed in an insulating resin such as polystyrene, vinyl chloride, vinyl acetate, acrylic, polycarbonate, polyamide, polyester, butyral, etc., and the above-mentioned. A charge generation layer in which pigments, selenium, selenium alloys, etc. are vapor-deposited or dispersed in the resin, and fused polycyclic aromatic compounds such as anthracene and perylene, and heterocyclic compounds such as pyrazoline derivatives, oxadiazole derivatives, and imidazole derivatives. , aromatic amine compounds such as triphenylamine derivatives,
Examples include a functionally separated photoconductor in which a charge transport layer formed by dissolving and dispersing a low-molecular charge transport substance such as an aromatic nitrile compound or a hydra C sone compound in the resin is laminated.

Examples of the thermosetting resin contained in the surface protective layer include polyurethane resin, epoxy resin, alkyd resin, thermosetting acrylic resin, and silicone resin.

Examples of the organic tin compounds used in the present invention include stannath octoate, dibutyltin-2-ethylhexoate, dibutyltin dioctoate, dibutyltin dilaurate, and triethyltin acetate.

The amount of the organic tin compound added to the surface protective layer is 0.01% to 10% by weight based on the thermosetting resin. 0.0
If it is more than 1% by weight, curing will be insufficient, and if it is more than 10% by weight, there will be adverse effects such as an increase in the residual potential of the photoreceptor.

As the electrical resistance adjuster, metals or metal oxides having a particle size of 109 Ω·α or less, particularly tin oxide, titanium oxide, antimony oxide, indium oxide, and solid solutions thereof having an average particle size of 0.3 μm or less, preferably 0.15 μm or less. 1
It is best to use seeds or a mixture of two or more kinds. The electrical resistance adjuster is preferably contained in the protective layer in an amount of 10 to 50% by weight.

To add the organic tin compound to the coating solution, after adjusting the coating solution of the surface coating layer material to a desired concentration, the organic tin compound is gradually added while stirring the solution. After the addition is complete, stirring is continued until the bath solution becomes uniform, and once it becomes uniform, it is quickly coated onto the organic photoconductive layer. A bar coater, applicator, spray coater, doctor blade, dip coater, etc. are used to apply the surface coating layer.

After coating, a surface coating layer having good surface hardness can be obtained by drying at ioo'a to 140'O for 3 to 5 minutes.

Hereinafter, the present invention will be specifically explained with reference to Examples and Reference Examples.

Example 1 35 parts by weight of tin oxide with an average particle size of 0.3 μm or less, 65 parts by weight of polyurethane and Dibutyltin dilaurate 0.
Apply 65 parts by weight of a uniform dispersion liquid by dipping,
A surface protective layer with a film thickness of 2 μm after drying was provided, and then 12
A photoreceptor with high surface hardness was obtained by leaving it in a drying zone at 0° C. for 3 minutes throughout the week.

When this surface hardness was measured using a Knoop hardness tester,
The hardness showed a high value of 35 (Kg/ml). Reference Example 1 A photoconductor was manufactured in the same manner as in Example 1 except that digtyltin dilaurate was not added. has a surface hardness of 26 (Kg/J),
A large difference was observed compared to that of Example 1.

Reference Example 2 A photoreceptor produced in the same manner as Reference Example 1 was
When hardened at ℃ for 16 hours, the surface hardness was 36 (K
f/mJ), and the hardness was comparable to that of Example 1.

Example 2 A photoreceptor was obtained in the same manner as in Example 1 except that the organic tin compound in Example 1 was changed to 0.5 parts by weight of dibutyltin dioctoate. This photoreceptor has a Knoop hardness of 37
(Kg/mJ), which was a high value.

Example 3 A photoreceptor was obtained in the same manner as in Example 1, except that the components in the surface protective layer in Example 1 were changed to 40 parts by weight of zinc oxide, 60 parts by weight of epoxy resin, and 1 part by weight of triethyltin acetate. The surface hardness of this photoreceptor is a4 (K9/J)
Example 4 70 parts by weight of polyurethane resin, 30 parts by weight of a solid solution of tin oxide and antimony oxide, and dibutyltin oxide were placed on a photoconductor in which selenium was steamed to a thickness of 60μ on an aluminum pipe. - a surface protective layer consisting of 80.6 parts by weight;
A photoreceptor was obtained by drying at 0°C for 5 minutes.

When this photoreceptor was set in a copying machine (FX-3500: Fuji Xerox) and copies were made, no scratches were observed on the photoreceptor even after 100,000 copies were made, and good images were obtained.

41L

Claims (1)

[Claims] Electrophotography characterized by having a surface protective layer on the organic photoconductive layer containing an electrical resistance regulator, a thermosetting resin, and an organic tin compound in an amount of 0.01 to 10% by weight based on the thermosetting resin. Methodology.