JPS6254274A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the image quality and durability of an electrophotographic sensitive body successively provided with an intermediate layer and photoconductive layer on a conductive base as a photosensitive body for a plain paper copying machine and a lithographic printing negative by using a polyester and isocyanate compd. as the essential component of the intermediate layer. CONSTITUTION:The liquid essentially consisting of the polyester and isocyanate compd. is coated by a smoothing roller on one surface of the conductive base and is dried by hot air to provide the intermediate layer thereon. The photoconductive material and solvent are then dispersed by a ball mill and the dispersion thereof is coated by a roll coater on the intermediate layer and is dried by hot air to form the photoconductive layer. The image quality is thereby improved; in addition, the durability when the photosensitive body is repeatedly used as the plain paper copying machine or used as the lithographic printing negative is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to electrophotographic photoreceptors, and more particularly to photoreceptors for plain paper copiers and lithographic printing having a specific intermediate layer between a conductive support and a photoconductive layer. The present invention relates to an electrophotographic photoreceptor useful as an original plate.

Prior Art Conventional electrophotographic photoreceptors generally have a photoconductive layer provided on a conductive support directly or via an intermediate layer of polyvinyl butyl, cellulose acetate, acrylic resin, or the like.

However, the former type of photoreceptor that does not have an intermediate layer has a disadvantage in that discharge breakdown occurs during cross-charging, resulting in image defects. On the other hand, the latter type of photoreceptor with an intermediate layer shows some improvement in image quality, but the adhesion between the intermediate layer and the support is still insufficient, so photoreceptors for plain paper copying machines When used repeatedly as an original plate for lithographic printing, there was a problem in durability due to electrical or mechanical damage. In order to improve this problem, intermediate layers composed of acrylic foam and polyisocyanate (Japanese Patent Publication No. 48-12927) and polyamides (Japanese Patent Application Laid-open No. 53-97433) have been proposed, but in recent years it has become particularly strict. The reality is that the current demand for durability has not yet been met.

Purpose It is an object of the present invention to provide an electrophotographic photoreceptor that solves the above-mentioned problems and can satisfy not only image quality but also durability.

Structure The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which an intermediate layer and a photoconductive layer are sequentially provided on a conductive support, and the main components of the intermediate layer are composed of polyester and an isocyanate compound. be.

Saturated polyesters are suitable as polyesters used in the intermediate layer of the present invention, and are easily available in a variety of commercially available products. For example, Nispel 1101.1102.1110.1310 manufactured by Hitachi Chemical.
1311.1320 and 1510; Nonoiron 200.290.103.300, 500.60 manufactured by Toyobo Co., Ltd.
0% 630.30PSGM900.0M400SGV
100 and GV700; Polyester Adhesive 4900 manufactured by DuPont, USA, and the like.

Specific examples of isocyanate compounds used in combination with these polyesters include toluene diinocyanate, triphenylmethane diisocyanate, metaxylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.
or trifunctional isocyanates and polyisocyanate adducts made from these, blocked isocyanates, polymerized polyisocyanates, etc. Commercially available products include Suronate L, HL, and 20 manufactured by Hhon Polyurethane Kogyo Co., Ltd.
No. 36; Desmodur L manufactured by A-Inil; and Adiprene LD-213 manufactured by DuPont. The amount of the isocyanate compound used is usually about 1 mole of NOO groups in the diisocyanate compound per 1 mole of OH groups in the polyester.

In addition, inorganic pigments such as clay and calcium carbonate can be added to the intermediate layer for the purpose of filling the base paper when the base paper is used as a support. The amount used is 0.5 to 0.5 to 1 layer of polyester and isocyanate mixture.
3 parts by weight is suitable.

The intermediate layer made of the above materials is formed by a normal coating method. The amount of adhesion is 0.3 to 51/n if it does not contain inorganic pigments? , 3 to 20 if it contains inorganic pigments
I is appropriate.

The photoconductive layer of the present invention is composed of an inorganic or organic photoconductor and, if necessary, a resin inder as the main components, just as conventionally. Examples of such photoconductive layers include amorphous selenium, amorphous silicon, and zinc oxide.
Resin dispersion layer, cadmium sulfide-resin dispersion layer, titanium oxide-resin dispersion layer, zinc sulfide-resin dispersion layer, lead oxide-resin dispersion layer, poly-N-vinylcarnozole-resin dispersion layer,
Halogenated poly-N-vinylcarbazole - resin dispersion layer, polyvinylpyrene - resin dispersion layer, polyginylanthracene - resin dispersion layer, pyrene formaldehyde condensation polymer - m fat dispersion 1i, d+) - r-carnosolyl ethyl L Examples include -1' lutamate to a resin-dispersed layer and a composite layer thereof. Note that the method for forming these photoconductive layers is completely the same as conventional methods, such as vapor deposition, sputtering, and coating methods.

In the case of a single layer of inorganic photoconductor, the amount of adhesion is 30 to 300. !
il~, 20~30 for inorganic photoconductor~resin dispersion layer
11/? ? ? , 5 to 5 for organic photoconductor to resin dispersion layer
30p~ is appropriate.

As the conductive support, a plate or foil of metal such as aluminum, copper, nickel, tin, or zinc; paper coated with or impregnated with a conductive agent such as polyvinylbenzyltrimethyl/quaternary ammonium chloride; foil of the above metal; Examples include paper or plastic films provided with a vapor deposition layer or a powder dispersion layer (dispersed in resin); and those precoated with hydrophilic or lipophilic resins such as polyvinyl alcohol, calxoxymethyl cellulose, and acrylic resins. It will be done.

The present invention will be explained below by way of examples. Note that both parts and percentages are based on weight.

Example 1 100 parts of a 40% solution of polyester (solvent: mixed yarn of toluene and methyl ethyl ketone, Nispel 1310 manufactured by Hitachi Chemical Co., Ltd.) and isocyanate were applied to one side of a conductive support made of aluminum foil with a thickness of 80 μm. 60% of the compound
A solution consisting of 5 parts of butyl acetate solution (Coronate 2036 manufactured by Nippon Polyurethane Industries Co., Ltd., NOO content approximately 10-11%), 100 parts of methyl ethyl ketone, and 200 parts of toluene was applied on a smoothing roller and dried with hot air to determine the amount of adhesion. An intermediate layer of 1.21i~ was provided. Next, 100 parts of photoconductive cadmium sulfide, 50 parts of a 50% toluene solution of acrylic resin (B-310, manufactured by Get Inc., USA), and 60 parts of toluene were dispersed using a 1-luminescent mill, and this was applied onto the intermediate layer using a roll coater. Coat with water and dry with hot air to reach a coating weight of 46.
An electrophotographic photoreceptor was prepared by forming a photoconductive layer of g/-.

The electrostatic properties of this product were investigated using a Peno e-analyzer (5P428 manufactured by Kawaguchi Electric Co., Ltd.) as follows. First, the sample was corona charged to 16 KV, the surface potential Vo was measured 20 seconds later, and then the surface potential V was measured by irradiating the sample with 3 lux light.

The amount of exposure (lux・
The residual potential Vps after irradiation with light for 30 seconds is determined.
o was measured. As a result, Vo is -47o■, El/1
0 was 8.2 lux*sec and Vpso was -7V, showing good characteristics.

Next, we set this photoreceptor in a dry-type electrophotographic copying machine for plain paper and conducted a durability test by continuous copying.
More than 1000 good copies were obtained.

On the other hand, as a comparative example, an electrophotographic photoreceptor was prepared in the same manner except that the intermediate layer was not provided, and a durability test was conducted. As a result, cracks and peeling occurred in the photoconductive layer after 100 copies or less.

As another comparative example, when an electrophotographic photoreceptor was prepared in the same manner except that no isocyanate compound was used, cracks appeared in the photoconductive layer during formation. This is thought to be because the intermediate layer was composed only of polyester, and the intermediate layer was swollen or partially dissolved by the solvent (toluene) used to form the light guiding layer.

Example 2 xo parts of 10% water m solution of polyvinyl alcohol, 8BR (styrene-butadiene copolymer) latex with a resin content of 48% (DL-e 36 manufactured by Dow Chemical Company, USA) z
1 part, 1.5 parts of a 30% aqueous solution of polyvinylbenzyltrimethyl quaternary ammonium chloride and 50% of clay
10 parts of an aqueous dispersion was applied to both sides of 120117m' moisture-resistant treated paper using an airbrush method, dried with hot air to form a conductive layer of adhesion, and then supercalendered to smooth both sides. A conductive support was prepared by

Next, polyester (manufactured by Toyobo Co., Ltd./
? 100 parts of a 10% solution of Iron 200 (solvent is an isotropic compound of methyl ethyl ketone and toluene) and a 75% solution of an isocyanate compound (an adduct of 3 moles of tolylene diisocyanate and 1 mole of trimethylolpropane) in ethyl acetate (Japan) Coronate L, N manufactured by Bori Urethane Kogyo Co., Ltd.
00 content approx. 74-76%) Apply 0.5 parts of the solution with a smoothing roller and dry with hot air to reduce the coating amount to 1.4 parts.
An intermediate layer of g~ was provided. The pot life of this intermediate layer forming solution was 24 hours or more at room temperature, and it did not cause any trouble in the work.

Next, 100 parts of photoconductive zinc oxide, 50% of acrylic resin.
40 parts of xylene solution (Rasdrazole 452 manufactured by Dainippon Ink Chemical Industries, Ltd.), 100 parts of toluene, 0 phthalic anhydride
．． 2 parts and 1.6 parts of 5% methanol solution of rose bengal
A Shimiko photographic photoreceptor was prepared by dispersing the same in a Dahl mill, applying it onto the intermediate layer using a roll coater, and drying with hot air to form a photoconductive layer with a coating weight of 23 g or more.

This product showed V in the same test as in Example 1.

is -54ov, E3 (is 16. Z lux 5eC
s VPao was 19 V, which showed good electrostatic properties, and the image quality was also good, showing durability of 1,000 sheets or more.

In addition, this photoreceptor was used with an electrophotographic engraving machine (Ricoh Company!!! LA).
After forming a dry toner image in step-2), insensitivity treatment and planographic printing were performed using a planographic printing machine (AP7000 manufactured by Ricoh Co., Ltd.) to obtain about 5,000 good printed materials. 50 again
When the elongation rate due to water absorption of the photoreceptor was examined when printing 00 sheets, it was found to be 0% in both the vertical and horizontal directions.

On the other hand, as a comparative example, the composition of the intermediate layer forming liquid was changed to a 50% toluene-butyl acetate mixed solvent solution of acrylic polyol (
An electrophotographic photoreceptor was prepared in the same manner except that 100 parts of Thermolac L-215 (manufactured by Souken Kagaku Co., Ltd.), 7.6 parts of Coronate L, and 200 parts of toluene were used.

Approximately 5,000 prints were obtained from this product in the printing test described above, and the elongation rate of the photoreceptor at this time was approximately 0.3% in the vertical direction.
, about 1.0% horizontally.

Example 3 Polyester (manufactured by Toyobo Co., Ltd.) Iron 300) 10
% solution (solvent is an isotropic compound of methyl ethyl ketone and toluene) 100 parts, titanium oxide 10 parts and coronet) L
1 part was dispersed with 2-lumil, applied to one side (felt side) of 901/rrl moisture-resistant treated paper using a roll coater, and dried with hot air to give a coating weight of 16 y7. An intermediate layer of z was provided.

Next, on the opposite side (wire side) of this intermediate layer, a conductive layer with an adhesion amount of 12 g or more was applied in the same manner as in Example 2, and then
Both surfaces were smoothed by calendering, and a photoconductive layer was further provided on the intermediate layer in the same manner as in Example 2, thereby producing a Shimiko photographic photoreceptor.

This photoreceptor received a V rating in the same test as Example 1.

is -570V, El/10 is 15.71uX 6m
, Vp3g was 16V, which showed good electrostatic properties, and the image quality was also good, showing durability for more than 1,000 sheets.

Effects As described above, since the electrophotographic photoreceptor of the present invention is composed of polyester and an isocyanate compound in the intermediate layer, the image quality is improved and it can be used repeatedly as a plain paper copier or as an original plate for lithographic printing. Durability is significantly improved.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising an intermediate layer and a photoconductive layer sequentially provided on a conductive support, wherein the main components of the intermediate layer are polyester and an isocyanate compound.