JPS6287970A - electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electrophotographic photoreceptor suitable particularly for use in plain paper copying (PPO) and lithographic printing plates.

2. Description of the Related Art As electrophotographic photoreceptors, there are known electrophotographic photoreceptors in which an adhesive layer is provided between a conductive support and a photoconductive layer.

This type of photoreceptor has improved durability due to the adhesive layer, so
Suitable for PPO and lithographic printing plates. Here, the material for the adhesive layer is a mixture of acrylic poly-17ol and incyanate (% Publication No. 48-12927), a mixture of a binder resin for the photoconductive layer such as acrylic resin or silicone resin, and an oil-soluble surfactant. Mixed systems of organic solvent-soluble resins and acids or salts, such as polyester resins (JP-A No. 56-87049), phthalic acid resins for paints, and polyvinyl acetal resins for paints, 40-7
No. 332), polyamide (Japanese Unexamined Patent Publication No. 53-97433)
etc. are used. Conventionally, when forming an adhesive layer using these materials, a normal coating method has been adopted. However, since aromatic, ketone, ester, and other organic solvents are used as the solvent for the coating liquid in this case, the conventional method includes the following problems.

1) Since flammable and toxic organic solvents are used, fire prevention equipment and solvent recovery equipment are required, which increases equipment costs, and regardless of the shape of the support, such as a sheet or a drum. However, when coating with an organic solvent, the coating equipment is limited to nine coating devices equipped with the above-mentioned equipment.

2) When inorganic pigments are used in the adhesive layer to control electrical resistance or fill paper to improve image quality, expensive titanium oxide, zinc sulfide, etc. may be used as pigments due to their dispersibility in organic solvents. It is difficult to use rays, calcium carbonate, etc., which are limited and inexpensive.

3) When the conductive support is made of paper, when providing the N-contact layer, the resin component in the coating solution permeates into the paper together with the solvent;
Adhesion strength decreases. To prevent this, it is necessary to further provide a solvent permeation prevention layer between the paper and the adhesive layer.

Moreover, some conventional adhesive layers do not have sufficient durability for PPO or lithographic printing plates.

Object The first object of the present invention is to provide an electrophotographic photoreceptor which eliminates all the drawbacks caused by organic solvents by using an aqueous coating liquid to form an adhesive layer.

A second object of the present invention is to provide an electrophotographic photoreceptor having sufficient durability for use in PPO and lithographic printing plates.

Structure In the electrophotographic photoreceptor of the present invention, a contact M layer is provided between the conductive support and the photoconductive layer by a coating method. It is characterized by using an aqueous coating liquid as the main component.

The adhesive layer of the present invention is thus formed using an aqueous coating liquid, and the polyester resin used in this coating liquid is contained as an emulsion, and the amino resin Hβ such as melamine resin or urea resin is contained as an aqueous solution. ing. Here, commercially available polyester resin emulsions include Vylonal MD-1200 and IMD-140 manufactured by Toyobo Co., Ltd.
0, MD-1530°MD-1900, etc. Commercially available amine resin aqueous solutions include Sumimaru M-50W (50% aqueous solution of methoxy melamine resin) manufactured by Sumitomo Chemical Co., Ltd., Sumiraze 613 (80% aqueous solution of methyl ether resin of limethylol melamine); Mitsui Toatsu Chemical Co., Ltd. Neelamine P-1500 (38% aqueous solution of urea resin), etc.

The ratio (solid content) of polyester resin and amino resin in the adhesive layer is suitably about 1:(0.1 to 0.8).

In addition, an inorganic pigment can be present in the adhesive layer as in the past. Examples of such pigments include titanium oxide, zinc sulfide, Merck, calcium carbonate, and clay. Usage amount: 0.5 to 3 parts per 1 part by weight of Bori Ester Forehead Fat
Parts by weight are appropriate.

The adhesive jΔ of the present invention is formed by coating and drying an aqueous coating solution containing an ester resin emulsion, an amino resin aqueous solution, and, if necessary, an inorganic pigment, on a conductive support. The adhesion layer is suitably applied in a range of 0.5 to 51 p/e when the resin is used alone, and from 3 to 20 p/c in the case of a mixture with a pigment.

In any case, if N'At is smaller than the lower limit,
Adhesive strength decreases, and on the other hand, if it is greater than the upper limit, electrophotographic properties will deteriorate and costs will increase.

The adhesive layer of the present invention thus formed has not only poor adhesive strength but also excellent solvent resistance and water resistance. In addition, this adhesive layer can be used to improve the durability of general direct printing type lithographic printing original plates, which have a hydrophilic image-receiving layer on a support such as paper (in this case, the adhesive layer is Therefore, the adhesive layer of the present invention is used when forming a resin-dispersed photoconductive layer or an image-receiving layer (for the former, an organic solvent-based coating liquid is used; for the latter, an aqueous coating liquid is used). Since it is not attacked by organic solvents or water, there are no manufacturing problems.

The photoconductive layer of the present invention is exactly the same as the conventional one, and includes an amorphous selenium layer, an amorphous silicon layer, an inorganic photoconductor (ZnO1Od8, etc.) to an insulating resin dispersion layer, an organic photoconductor (polyvinyl carnosol or its derivative, polyvinylanthracene or its derivatives, etc.), an insulating resin dispersion layer, and a laminate thereof. Furthermore, the method of forming the light guide re and the amount of deposit may be exactly the same as in the prior art.

As the conductive support, metal (cylindrical, plate-like or foil), paper or plastic film subjected to conductive treatment, etc. are used.

The present invention will be explained below with reference to Examples and Reference Examples. Note that both parts and percentages are expressed on a weight basis.

Example 1 fill) 30% polyester emulsion (trade name Vylonal MD-1900 manufactured by Toyobo Co., Ltd.) 100
and 20 parts of an 80% aqueous solution of melamine resin were mixed well, and this was coated on one side of 100 μm thick aluminum foil using a roll coater, and dried at 110C for 5 minutes to give a coating weight of 1.21.
An adhesive layer of 1 part m' was applied. Next, photoconductive zinc oxide 10
0 parts, mineral spirit solution of silicone resin-modified alkyd resin with a solid content of 60% (Alloprats 1700, manufactured by Kuuchaku Arrow Chemical Co., Ltd.) 36 parts, mineral spirit 10
0 parts, 0.2 parts of phthalic anhydride and 5% of Rose Bengal
1.6 parts of methanol solution was kneaded using a Zeel mill, and this was applied onto the adhesive layer using a roll coater.
After drying for a minute, apply approximately 239 parts m' of the photoconductive layer.

The obtained photographic photoreceptor's 4 layers of light guide and the 3 layers of lff! The strength was measured using the pine wax test (JISP812
9-76) and a good score of 9-10. In addition, this photoreceptor was tested for durability by continuous copying using a commercially available plain paper copying machine (product name FT=4700 manufactured by Ricoh Co., Ltd.) using a one-component dry toner. The number of copies made before scumming occurs) showed durability of 1000 or more.

On the other hand, as a comparative example, an electrophotographic photoreceptor prepared in the same manner as in this example except that no adhesive layer was provided had a low adhesive strength of 3 to 4 in the same test, and the durability at t7 was 50 sheets or less. Peeling of it I. and J occurred. Further, an electrophotographic photoreceptor prepared in the same manner as in this example except that the 80% aqueous solution of melamine resin i fat was not used had an adhesive strength of 6 to 7 and a durability of 400 to 500 in the same test.

Example 2 Moisture-resistant treated with melamine resin, t basis weight 1101! By impregnating /nl paper with a methanol solution of polyvinylbenzyl trimethyl quaternary ammonium chloride,
A conductive support was prepared to have a volume resistivity ρV of approximately 8×10′Ω at room temperature and humidity. Next, 0.4 parts of a 50% aqueous solution of urea resin, 333 parts of a polyester emulsion with a solid content of 30% (same as in Example 1), and 4 parts of a 50% aqueous dispersion of clay were mixed in a mixer, and this was mixed with the above-mentioned conductive material. After coating on one side of the support and drying at 130C for 1 minute to provide an adhesive layer with a coverage of about 15 g/l, this layer was smoothed by supercalendering. Next, 100 parts of photoconductive zinc oxide, 50% xylene solution of acrylic resin (trade name: Lasdrazol 4, manufactured by Dainippon Ink Chemical Industries, Ltd.)
52) Knead 40 parts of anhydrous phthalate, 2 parts of anhydrous phthalate, 1.6 parts of a 5% methanol solution of rose bengal, and 100 parts of toluene in a Zeel mill, apply this onto the adhesive M using a roll coater, and apply the mixture to 120C. After drying for 1 minute, a photoconductive layer with a coating weight of 25 g or more was provided.

The obtained electrophotographic photoreceptor exhibited adhesive strength of 1ON11 and durability of 1000 sheets or more in the same test as in Example 1.

Example 3 1 part of a ester emulsion with a solid content of 34% (trade name: Vylonal MD-1200, manufactured by Toyobo Co., Ltd.), 0, 5 parts of a 50% aqueous solution of methoxy melamine resin (trade name: Sumimaru M-50W, manufactured by Kaito Kagaku Kogyo Co., Ltd.), and Clay's 5
4 parts of the 0% aqueous dispersion were mixed in a mixer, and this was coated on one side of the conductive support prepared in Example 2 using a roll coater, and dried at 130C for 5 minutes to give a coating weight of 131! /@″
After applying the adhesive layer, this layer was smoothed by supercalendering. Next, on this contact ff layer, Example 2 is applied.
In the same manner as above, an electrophotographic photoreceptor was prepared by providing a photoconductive layer with a coating amount of 25 E/ln''.

This product exhibited good performance exactly like the photoreceptor of Example 2.

Next, the photoreceptor of this example was made into a lithographic printing plate using an electrophotographic printing machine (product name: LA-2, manufactured by Ricoh Co., Ltd.) containing a one-component wet toner, and this was used in an offset printing machine (product name: LA-2, manufactured by Ricoh Co., Ltd.). After desensitizing the sample using a product (trade name: AP-7000), it was subjected to offset printing, and more than 1,000 good prints were obtained.

Reference Example A polyester emulsion with a solid content of 15% (product name: Vylona manufactured by Toyobo Co., Ltd.
l MD-1400) 100 parts and 50% of urea resin
An aqueous coating solution consisting of 15 parts of an aqueous solution was applied and dried with hot air at 130C for 15 seconds to form adhesive layers with a coating weight of 2.517 m'' each.Next, 10 parts of a 10% aqueous solution of PVA and 10 parts of calcium carbonate were applied. 3 parts of a 50% aqueous dispersion, 0.2 part of an 80% aqueous solution of methylolmelamine resin, and 1 part of a 1% aqueous solution of ammonium chloride were thoroughly mixed with a mixer, and this was applied onto both adhesive layers with an airbrush. 20 with hot air
The image-receiving layers were dried for 2 seconds to form image-receiving layers each having a coverage of about 1617 m', and then both image-receiving layers were smoothed by suit-calendering.

The resulting direct-drawing lithographic printing original plate was coated with one-component dry toner and passed through a plain paper copying machine (product name: FT6600 manufactured by Ricoh Co., Ltd.).
When plate-making was performed, a good toner image was formed on one side. Note that plate making can be done on both sides. Next, this was used as a lithographic printing plate, and an offset printing machine (product name: AP-16 manufactured by Ricoh Co., Ltd.) was used.
After desensitization treatment with 00), offset printing was performed, and more than 500 good prints were obtained.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor in which an adhesive layer is provided between a conductive support and a photoconductive layer by a coating method, an aqueous coating liquid containing a polyester resin and an amino resin as main components is used to form the adhesive layer. An electrophotographic photoreceptor featuring: