JPS5937499B2 - Photosensitive materials for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrophotography, particularly to improvement of image fixing properties and retouchability of electrophotography using organic photoconductive materials.
More specifically, by dispersing an appropriate amount of low molecular weight polyethylene in the photosensitive layer of an organic photoconductor for electrophotography, image fixability and ease of writing with a pencil or the like are improved.

Conventional electrophotographic photosensitive materials having an organic photoconductor photosensitive layer use, for example, metal, conductive treated paper, tracing paper, various plastic films, glass, etc. as a support; by applying a thin layer of an organic photoconductor in a manner known in the art.

The organic photoconductor photosensitive layer is made of an organic photoconductor that itself has film-forming properties, such as a polynuclear aromatic vinyl polymer, a vinyl polymer having a hetero side chain, or
If it does not have film-forming properties by itself, for example, oxadiazole-based, thiazole-based, thiadiazole-based, triazole-based, imidazolone-based, oxazole-based, imidazole-based, pyrazoline-based, imidazolidine-based, pyrazine-based, triazine-based, oxazolo-based , quinoxaline series, giazoline series, furan series, acridine series, carbazole series, phenothiazine series, allylamine series, etc., other polymeric substances having suitable film-forming properties, such as phenol resins, alkyd resins, polyester resins, etc. , diallyl phthalate resin, epoxy resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, styrene resin, styrene copolymer resin, methacrylic resin, acrylic ester resin, polyamide resin, polyphenylene oxide resin,
Polysulfone resin, polycarbonate resin, etc. are used as a binder and are used in appropriate proportions.

Furthermore, as a sensitizing agent, for example, Victoria Blue B,
Crystal violet, methyl violet, malachite green, rhodamine B, rhodamine 6G) rose bengal, fluorescein, methylene blue, etc. are used, and chemical sensitizers include, for example, tetracyanoethylene, tetracyanoquinodimethane, bromanil, chloranil, benzoquinone. , naphthoquinone, anthraquinone and its derivatives, p-nitrophenol, picric acid, 1,
3,5-trinitrobenzene monochloroacetic acid and the like are used. The organic photoconductor photosensitive layer thus obtained is
Since the support itself is transparent, a transparent support is selected and is often used as a second original for diazo copying.

However, since the surface is extremely smooth, when an image is created using, for example, a known wet electrophotography method, the toner has poor fixing properties and even a light touch with a finger causes the image to come off. Furthermore, since the surface of the photosensitive layer is smooth, there is almost no possibility of drawing on it with a pencil or the like. Conventionally, in order to improve these, various pigments,
For example, calcium carbonate, zinc oxide, titanium oxide, colloidal silica, glass powder, talc, organic metal salts, etc. have been dispersed, but these have fatal drawbacks such as sedimentation and aggregation of pigments, decreased sensitivity, and decreased amphoteric concentration. Furthermore, there are many practical problems such as a decrease in transparency when used as a second original for diazo copying. In contrast, the present inventors have used low molecular weight polyethylene, that is, one with a molecular weight of 1,000 to 15,000, preferably 1,500 to 5,000, at a maximum of 50% by weight based on the total solid content contained in the organic photoconductor layer. Preferably 1
By dispersing it in an amount of 0 to 40% by weight, the defects that were difficult to solve with the above-mentioned inorganic pigments were solved, and the writing properties with a pencil etc. were improved, and the fixability of images in wet electrophotography was also improved. Methods for dispersing low molecular weight polyethylene in an organic photoconductive layer include various organic solvents such as aromatic hydrocarbons such as benzene, toluene, and xylene, carbon tetrachloride, trichloride, and chloroform. The fact that it dissolves in monochlorobenzene, etc. when hot, but does not dissolve when cold can be utilized. For example, when 2 parts of low molecular weight polyethylene is added to 8 parts of monochlorobenzene and the mixture is heated to 70° C. or higher, it dissolves completely transparently. When this is cooled to room temperature, the low molecular weight polyethylene no longer remains in a dissolved state, but precipitates into very fine particles and becomes a good matting agent. moreover,
Examples will be described to explain the present invention in detail, but the present invention is not limited thereto. Example 1. N,N,NZ mertetrabenzyl-m-phenylenediamine (organic photoconductor) 109 and Iupilon N-3 (manufactured by Mitsubishi Gas Chemical, trade name of polycarbonate resin) 89 and p-nitrophenol (chemical sensitizer) 1.59 was dissolved in monochlorobenzene 1009, and this was designated as A.

Next, Sanwax 161p (manufactured by Sanyo Kasei, trade name of low molecular weight polyethylene, molecular weight, approximately 5000) 39 and monochlorobenzene 12fI were mixed and dissolved at a temperature of 70° C. or higher, and this was designated as B. B is cooled to room temperature to precipitate low molecular weight polyethylene into fine particles. B made like this inside A! 4. Mix and make a uniform dispersion liquid by ultrasonic dispersion. To this, 5 d of 1% N,N-dimethylformamide solution of crystal violet was added to conductive treatment.
The organic photoconductive material was coated onto glossy tracing paper (manufactured by Mitsubishi Paper Industries, trade name: Tracing Paper) using a wire bar so that the dry weight was 69/Trl. This uniform dispersion was left to stand for 48 hours, but no sedimentation or aggregation occurred. Moreover, the photosensitive surface of this product was a uniform matte surface, and additions with a pencil were good.
Next, printing was carried out using a wet type electrophotographic copying machine (manufactured by Sanda Kogyo KK, A-2 Auto), and a copy with high density and no fog was obtained. The image area of this copy did not come off even when rubbed with fingers, and the fixing properties were good. For comparison, colloidal silica 39 was placed in A in place of the matting agent B in this example and ultrasonic dispersion was carried out, but it took a long time to obtain a uniform dispersion and the particles were also somewhat large.

Furthermore, colloidal silica aggregated in this liquid in about 24 hours. In addition, when printing was performed after coating on the support as in this example, it was found that the areas with large colloidal silica particles were
This resulted in fogging, and only a low density product was obtained overall. Example 2. In place of Sunwax 161P in Example 1, Sunwax 131P (polyethylene manufactured by Sanyo Chemical Co., Ltd. having a molecular weight of about 3,500) was used in the same manner as in Example 1, and good results were obtained.

Example 3. When the same procedure as in Example 1 was performed using Sunwax 171P (polyethylene manufactured by Sanyo Chemical Co., Ltd. with a molecular weight of about 1500) in place of Sunwax 161P in Example 1, good results were obtained.

Example 4. N,N,ma,mertetraphenyl-p-phenylenediamine (organic photoconductor) 109 and Dialex HH-
102 (product name of polyethylene manufactured by Mitsubishi Monsanto Chemical) 10f! and 4-chloro-m-cresol (chemical sensitizer) 19 in xylene 90f! This is called A.

Next, add Sanwax 161P49 to xylene 16 and 70
B is obtained by heating and melting at a temperature of ℃ or higher. When A was kept at room temperature and B was added in a dissolved state while stirring, Sunwax 161P precipitated into fine particles to obtain a uniform dispersion. Add 5 ml of a 1% N,N'-dimethylformamide solution of crystal violet to this and place it on a conductive treated glossy tracing paper with a dry weight of 69/M2.
An organic photoconductive photosensitive material was obtained by coating with a wire bar so that the following results were obtained. This uniform dispersion was allowed to stand for 48 hours, but no problems such as sedimentation or aggregation occurred. Furthermore, the photosensitive surface of this product had a uniform fine matte surface, and additions with a pencil or the like were good. Next, printing was carried out using a wet type electrophotographic copying machine, and a high-density, fog-free copy was obtained. The image area of this copy does not come off easily even when rubbed with fingers, and has good fixing properties. Next, this electrophotographic copy was used as the second original and Copister Dash 300 (manufactured by Sanda Kogyo KK,
When diazo copying was performed using a diazo copying machine (trade name), proper images and clear image quality were obtained with dial 12 (dials 1 to 20, the higher the number, the faster the speed). For comparison, titanium oxide 49 was placed in A instead of the matting agent B of this example, and a uniform dispersion was obtained by ultrasonic dispersion.

Claims (1)

[Claims] 1. An organic electrophotographic photosensitive material characterized in that low molecular weight polyethylene is dispersed in an electrophotographic photosensitive layer using an organic photoconductor on a support.