JPS6022347B2 - Binder-based electrophotographic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a binder-based electrophotographic material that can be used repeatedly.

Electrophotography requires a photoconductive layer (hereinafter referred to as photosensitive layer).
After forming a static latent image on a toner image, it is developed with a developer to form a toner image and then fixed on the photosensitive layer as it is. There is a known method of fixation. In the latter method, in which an image is formed by transferring a toner image to transfer paper, a photosensitive layer is made of vapor-deposited selenium, and a photoconductive powder such as lead oxide, cadmium sulfide, or cadmium selenide is used as an insulating resin. Some use a binder-based photosensitive material dispersed inside.
Recently, electrophotographic materials having a binder-based photosensitive layer instead of a selenium photosensitive layer have been used in repeat transfer type mother-child photocopiers.
However, in general, such binder-based electrophotographic materials are repeatedly used in the process of forming images by using a developing brush,
The surface of the photosensitive layer may be damaged and deteriorated by cleaner brushes, transfer paper, etc., and the photosensitive layer may be decomposed and deteriorated by current and light due to repeated corona charging and image scanning, resulting in a decrease in the quality of the copied image. It is something. An object of the present invention is to provide a binder-based electrophotographic material which does not have the various drawbacks mentioned above and which does not cause deterioration of copied images even after repeated use. The present inventors have found that a photoconductive photosensitive layer provided on a guiding fin support of a binder-based electrophotographic photosensitive material contains a thermosetting acrylic resin, a thermosetting amino resin, and a thermosetting or thermoplastic silicone resin. It has been found that the above object can be achieved by doing so. That is, in such a binder-based electrophotographic photosensitive material, the surface of the photosensitive layer of the photosensitive material has high mechanical abrasion resistance, and is not damaged by repeated friction with a developing brush, cleaning brush, transfer paper, etc. Furthermore, even if corona charging and image exposure are repeated, the photosensitive layer will not deteriorate.

Furthermore, since the photosensitive layer is insoluble in green type developer, it is also possible to perform repeated copying even in a wet type developer. Examples of the photoconductive material used in the present invention include organic or inorganic photoconductive materials such as zinc oxide, zinc sulfide, cadmium sulfide, cadmium selenide, titanium oxide, and polyvinylcarbazole. Examples of sensitizers for such photoconductive materials include rosebencal, promphenol blue, promthymol blue, and acridine orange. The thermosetting acrylic resin, thermosetting amino resin, thermosetting or thermoplastic silicone resin used in the present invention are all conventionally known, and thermosetting acrylic resin refers to acrylic resin that does not have a functional group. It is a copolymer consisting of a vinyl monomer such as styrene, pinyltoluene, or other vinyl monomer, and an acrylic monomer having a functional group component that can be crosslinked with an amino resin or an epoxy resin.

Examples of crosslinkable functional groups include a group, a CQO group (where R is an alkyl group), and a group, and typical examples of the thermosetting acrylic resin used in the present invention include, for example, A structure represented by the following general formula [wherein R is a hydrogen atom or an alkyl group, and x, y, and z represent the number of polymerized moles] is used, and a commercially available product is Dianal HRI 12. manufactured by Mitsubishi Rayon Co., Ltd. 116,124・182'405 607
, 623 Muscle uniformity unevenness 0 and unevenness 7: Akridik N-752-451J, A-405 manufactured by Nihon Reichhold Co., Ltd.
There are 400 and 407 etc.

Examples of thermosetting amino resins used in the present invention include melamine resins, urea resins, and polyamide resins, but melamine resins are preferred.
(Methylated melamine resin): Melamine-2 manufactured by Nippon Kasei Co., Ltd.
0 (butylated melamine resin): Super Beckamine J-820, G-821, L-101,1 manufactured by Dainippon Ink Co., Ltd.
03104 and 105 (butylated melamine resin): Nippon Carbide Co., Ltd. Nikalatsuku BL-60 (butylated penzoguanamine): Fuji Kasei Co., Ltd. Delamine T-1 billion (butylated penzoguanamine), and the like.

As the silicone resin used in the present invention, there are useful silicone resins that are generally commercially available for paints and insulating materials, such as KR-211, 21 manufactured by Shin-Etsu Chemical Co., Ltd.
2,213,214,251,253,255,260
,261,266,267,271,272,275,
278, 280, 282, 285 Toyo Rayon Silicon Co., Ltd. GP-77, DC-1090, 1092, SH-
802, 803, 804, 805, 806, 808, 8
40,901,902,903,904,935,93
6, 9 evil, 996, 997, 1820, 1830, 18
40, 1850, 1851, 1860, 1870, 1 spot 0, 1890, 3150, 6616, 7501, 752
There is a first prize. Although the photosensitive layer of the electrophotographic light-sensitive material according to the present invention can exhibit excellent Shigeko photographic performance without heat treatment, when heat treatment is applied, the thermosetting acrylic resin and amino resin are bonded to each other. Although it is possible to form a photosensitive layer with high abrasion resistance by forming a strong film by causing a cracking reaction, the problem is that toner toner adheres to the surface of the photosensitive layer during repeated copying processes and deteriorates image characteristics. It was observed.

On the other hand, by adding silicone resin in addition to thermosetting acrylic resin and amino resin, it is possible to prevent toner from adhering to the surface of the photosensitive layer, and to prevent deterioration of the photosensitive layer due to repeated corona charging and image exposure. The number of repeated copies can be greatly increased. Furthermore, by adding an epoxy resin to the binder resin in the photosensitive layer of the present invention, if necessary, the drying time after coating the photosensitive liquid on the support can be significantly shortened, improving manufacturing efficiency. At the same time, the coating properties of the photosensitive layer can be further improved. In this way, the present invention improves the abrasion resistance, stain resistance, voltage resistance, etc. of the photosensitive layer by using a mixture of three or, if necessary, four types of resins having different structures. This makes it possible to provide a binder-based electrophotographic material suitable for repeated use. The mixing ratio of the binder resin used in the photosensitive layer according to the present invention is 0.0 amide/resin to 1 part by weight of thermosetting acrylic resin.
5 to 1 parts by weight, 0.05 to 5 parts by weight of silicone resin, preferably 0.1 to 0.3 parts by weight of amino resin, 0.1 to 2 parts by weight of silicone resin, preferably 1 part by weight of thermosetting acrylic resin. A good range is 0.1 to 1.0 parts by weight of epoxy resin per 1 part by weight of thermosetting acrylic resin when adding epoxy resin as necessary. The range is parts by weight. The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereby. *Example
1. A photosensitive solution with the six types of formulations listed in Table 1 is applied to a conductive base paper obtained by laminating a 100mm thick aluminum film onto a 100mm thick polyester film and providing a casein subbing layer thereon. was applied so that the film thickness when dried was 30 minutes/day and dried with hot air at 70 minutes.

Thereafter, a heat treatment was performed for 60 minutes in a 100 qo dryer to prepare an electrophotographic light-sensitive material, and a sample (Sample Shame.1) and comparative samples (Samples M.2, 3, 4, 5, and 6) were prepared. Table 1 However, the zinc oxide in Table 1 is SAZEX 400 manufactured by Sakai Chemical Co., Ltd.
0 Acrylic resin is Dianal HR- manufactured by Mitsubishi Rayon Co., Ltd.
169 (a 50% mixed solution of n-butyl alcohol and xylene), the melamine resin is Supervetsukamine J-820 manufactured by Nippon Reichhold (a 50% mixed solution of n-butyl alcohol and xylene), and the silicone resin is KR manufactured by Shin-Etsu Chemical Co., Ltd. -214 (70% toluene solution) and Rose Bengal were used as 2% methyl alcohol solutions, respectively.

These samples and comparative samples were transferred to a repetitive copying type electronic copying machine U-
200 using BIX200 clothing (4, manufactured by Nishiroku Photo Industry Co., Ltd.)
The results of repeated copying 0 times are shown in Table 2.

Table 2 Dmax is the image density of the copy sample when the original density is 1.0 and is copied 2000 times, Dfog is the image density of the copy sample when the same 200m group is copied, and "scratches and stains" are the image density of the copy sample when the original density is 1.0. The degree of "scratches and stains" caused by the developing brush, cleaning brush, transfer paper, etc. on the copy sample when copying is 0 (none), 1 (slight), 2 (slightly), 3 (extremely)
This is the value when displayed in four stages.

Claims (1)

[Claims] 1. A binder-based electrophotographic photosensitive material characterized in that a photoconductive photosensitive layer provided on a conductive support contains a thermosetting acrylic resin, a thermosetting aminol resin, and a thermosetting or thermoplastic silicone resin. material.