JPS5925214B2 - Color electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color electrophotographic method for obtaining improved color images, and more specifically, a colorless and transparent toner is added to a color image obtained by a conventional color electrophotographic method. This invention relates to an improved color electrophotographic method for forming images by overlapping images.

Conventionally, in color electrophotography using a color layering method, color printing is done by projecting the color image of the original through blue, green, and red color separation filters onto an electrophotographic photoreceptor for each color. A latent image is formed and then developed with extra color toner of each color separation filter, that is, yellow, magenta, and cyan toner, thereby superimposing the toner images of each color to form a multicolor image. .

Of course, various methods have been used in the past for forming electrostatic latent images in the color electrophotography method.

For example, there is a method of using zinc oxide paper as a photoreceptor and forming a color image directly on the zinc oxide paper, or a method of sequentially transferring the separated images of each color formed on the photoreceptor onto another transfer material. There is also a method of forming a color image by overlapping colors. However, all methods have the same color overlapping, and the formed color image is still a combination of yellow, magenta, and cyan toner images. However, if each of these color images is firmly fixed on the photoreceptor or transfer material, there is no problem, but if the toner image collapses due to friction, color bleeding will occur at the edges of the image, impairing the image quality. This is especially a problem when a wet developer is used because the heat fixation is not as strong as with a dry developer.

Therefore, in the past, this drawback was often solved by spraying a resin liquid onto the color image. However, in this case, a resin coating is formed on all areas where there is no image, giving the impression that the entire print has been treated with resin, which is extremely inappropriate, especially when it is desired to make the most of the surface of the transfer material.

Furthermore, it is technically difficult to automatically apply the resin liquid and dry it quickly, and it is not easy to introduce this method into an automatic color copying machine. It is also desirable to provide a coating to the toner image in order to improve the weather resistance of the color stamp image.

Particularly in the case of multicolor prints, if even one color fades, the color balance will be disrupted and the image quality will deteriorate. From this point of view, it is also necessary to easily cover color images. The object of the present invention is to solve the above-mentioned problems.

The present invention also provides a method for obtaining glossy color images with high image density. Furthermore, the present invention provides a method for obtaining color images that have improved weather resistance and light resistance and that do not fade during storage. To achieve the above object, the present invention is directed to a color electrophotographic method in which a latent image corresponding to a color separation image is developed with color toner to obtain a color image. A color electronic device comprising, after the color image forming step, developing the color image with a resin toner that does not contain a colorant, and fixing the color toner to the surface resin toner on the image support. It's in the photography method.

Furthermore, the present invention further forms an image by superimposing a resin toner containing at least no coloring material and an ultraviolet absorber by electrophotography on the color image formed by the color overlapping method. In color electrophotography.

The electrophotographic method of the present invention can be applied to both an electrophotographic method for forming a color image on photosensitive paper and a transfer type electrophotographic method for forming a color image on a transfer material.

In the former case, the process of forming the final surface layer with resin toner charges the photoreceptor, and without using a color separation filter, accurately aligns the original image and projects it onto a color image. Therefore, an electrostatic latent image corresponding to the original image is formed on the color image, and this is developed by using the resin toner described above. In the latter case, an electrostatic latent image corresponding to the original image is formed on the photoreceptor by an electrostatic latent image forming process that involves directly projecting the image of the original onto the photoreceptor without using a color separation filter. An image is formed, developed with resin toner, and transferred by accurately aligning the image with the color image already formed on the transfer material. Even if the resin toner used in the color electrophotography method of the present invention is a dry developer,
Of course, a liquid developer may also be used.

The color prints obtained by the present invention have excellent weather resistance and light resistance, do not change color easily, and do not lose their color balance for a long time.

Furthermore, the resin coating can significantly prevent light scattering on the surface of the image, thereby increasing the image density. However, since the non-image area of the print can take advantage of the surface quality of the photosensitive paper or transfer material, an interesting color print can be created. Furthermore, in carrying out the present invention, it is sufficient to add one step of ordinary electrophotography;
It can be easily introduced into a conventional color electrophotographic copying machine, and thereby it is possible to obtain an effect equal to or superior to that of conventional spray resin coating. The resin used in the toner made of resin particles containing no colorant used in the present invention is generally a colorless or almost colorless transparent resin, but preferably has a softening point in the range of 50 to 150°C. Things are good.

Typical examples include polyvinyl chloride, polyvinylidene chloride, vinyl chloride monovinylidene chloride copolymer, chlorinated polypropylene, vinyl chloride vinyl acetate copolymer, vinyl chloride monovinyl acetate monomaleic anhydride. Copolymer, ethyl cellulose, nitrocellulose, polyarylate ester resin, linseed oil-modified alkyd resin, rosin-modified alkyd resin, phenol-modified alkyd resin, phenol resin, polyester resin, polyvinyl butyral resin, polyisocyanate resin, polyurethane resin, polyvinyl acetate, Polyamide resin, Chroman resin, Dammar resin, ketone resin, maleic acid resin, polystyrene, low molecular weight polyethylene, phenol-modified pentaerythritol ester, colophonium, styrene-indene-acrylic nitrile copolymer, styrene-indene copolymer, styrene-acrylic Nitrile copolymers, styrene-butadiene copolymers, and the like can be used alone or in combination.

Various compounds are known as ultraviolet absorbers to be added to the transparent resin toner of the present invention, such as phenyl salicylate, P-octylphenyl salicylate, and 4-tert-butylphenyl salicylate. Salicylic acid derivatives such as enyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,
Benzophenone derivatives such as 5-chloro-2-hydroxybenzophenone and resorcinol monobenzophenone, benzotriazole derivatives such as 2-(2′-hydroxy-5〃-methylphenyl)benzotriazole, substituted acrylonitrile, hexamethylphosphoric Triamides, aromatic ester compounds, organic phosphorus compounds, organic sulfur compounds, etc. are used.

The present invention will be explained below in detail with reference to Examples, but the present invention is not limited to these Examples, and it is clear that various transparent resins and ultraviolet light inhibitors can be used.

[Example 1] Picostic D-75 (Etsuo, manufactured by Standard Oil Co., Ltd., polystyrene) 10 g Picoflex 100 (styrene-indene-acrylic nitrile resin, manufactured by Pico) 59 Solp Bottles 1205 (manufactured by Asahi Kasei Corporation, styrene, (ptadiene block copolymer)
39 The above composition was mixed and ground and milled in a ball mill for 30 hours with 80 ml of Isopa-H (Etsuso, an aliphatic hydrocarbon manufactured by Standard Oil Co., Ltd.) to obtain a concentrate.

A developing solution was prepared by dispersing 50 ml of this concentrated solution and 30 to 30 ml of zirconium octate in Isopa HIOOOd. On the other hand, electrophotographic paper using zinc oxide (manufactured by Tomoekawa Paper Co., Ltd.) was corona charged at -6 KV, and then an enlarged image was irradiated with a positive microfilm.
A positive colorless image was obtained by forming an electrostatic latent image and immersing it in the developer, which was completely fixed by an infrared heater.

Next, prepare a positive image formed with a colored liquid developer on the same electrophotographic photosensitive paper using the above positive microfilm, align it accurately, and apply it on top of the colored image under the same conditions as above. An image was formed using colorless resin toner and fixed using an infrared heater. Image formed by overlapping resin toner (4) and image not covered by resin toner (B)
), the difference shown below occurred. [Example 2] Picola.

Stick D-100 (Etsuso, Standard Oil Co., Ltd.)
Polystyrene) 5g Super Betsukasite 1126
(manufactured by Dainippon Ink and Chemicals Co., Ltd.) 5p Picoflex 105 (styrene-indene-acrylonitrile copolymer manufactured by Pico) 5g K Luprene 1205 (styrene ptadiene flock copolymer manufactured by 7! Kasei) 31 The above composition was mixed and ground. The resulting mixture was milled in a ball mill for 30 hours with 80 ml of Isopa-H to obtain a concentrated solution.

A developing solution was prepared by dispersing 50 Tf11 of this concentrated solution and 30 to 30 Tf11 of lecithin in Isopa1HlOOOOml. On the other hand, 100 g of microcrystalline cadmium sulfide was placed on an aluminum foil with a thickness of 0.05 mm.
%, 10 g of toluene solution, and 80 g of toluene were applied to a dry coating thickness of 40 tt and dried.
A polyester film having a thickness of 38p was pasted thereon using a room temperature curing epoxy resin adhesive to produce a three-layered photoreceptor. This photoreceptor is charged with a +7 KV corona, then subjected to an AC corona charge of 7 KV at the same time as image exposure, and then the entire surface is uniformly exposed to form an electrostatic latent image.
By developing this with the developer described above, a good positive transparent image was obtained. When a transfer paper was placed on this image and charged to +6 KV from the back and the transfer paper was peeled off, most of the image on the photoreceptor was transferred to the transfer paper and an image made of colorless resin toner was obtained.

Next, prepare a transferred image using a colored liquid developer in the same manner as in Example 1, perform accurate alignment, and form colorless resin toner image-wise on the colored image under the same conditions as above. did.

The obtained transferred image is melted and fixed on an infrared heater,
As a result, the same effect as in Example 1 was obtained in comparison between an image coated with resin toner and an image not coated. [Example 3] The same method as in [Example 1] was carried out by adding 0.59% of Seesorb 201 (phenyl salicylate manufactured by Shiraishi Calcium) as an ultraviolet absorber to the composition of the transparent resin toner in Example 1. A toner made only of resin was prepared and developed to obtain a superimposed image and an image made only of colored developer.

The superimposed image containing hydroxybenzophenone showed extremely little deterioration of the resin and change in the colored image in a sunlight exposure test compared to the image not containing SeaSorb 201. [Example 4] In Example 1, Teinupin P was used instead of Seesorb 201 as an ultraviolet absorber in the resin composition.
[Example 1] The same test as in Example 1 was conducted with the addition of 0.59% of 2-(27-hydroxy-5/methylphenyl)benzotriazole, manufactured by Kirkey Co., Ltd., and similar results were obtained.

[Example 5] Similar results were obtained in [Example 2] using Ester Resin 30 (polyester manufactured by Toyobo Co., Ltd.) in place of Super Betsukasite 1126 in the resin composition.

[Example 6] In [Example 2], Ester Resin 20 (Toyobo Co., Ltd.) was used instead of Super Betsukasite 1126 in the resin composition.
Similar results were obtained using a polyester made of polyester.

[Example 7] Seesorb 20 was used as the ultraviolet absorber in [Example 3].
Using Arichte 200 (manufactured by Kyodo Yakuhin Co., Ltd.) instead of 1,
As a result of conducting the same sunlight exposure test as in Example 3, similar effects were obtained.

[Example 8] Same sunlight as in [Example 3] except that SeaSorb 100 (2,4-dihydroxybenzophenone manufactured by Shiraishi Calcium Co., Ltd.) was used instead of Seasorb 201 as the ultraviolet absorber in [Example 3]. A similar effect was obtained as a result of an exposure test conducted with

[Example 9] Seesorb 20 was used as the ultraviolet absorber in [Example 3]
Instead of 1, SeaSorb 104 (manufactured by Shiraishi Calcium Co., Ltd. 2)
-Hydroxy-4-octadecyloxybenzophenone)
A sunlight exposure test similar to that in Example 3 was conducted using the same method as in Example 3, and as a result, similar effects were obtained.

[Example 10] Seesorb 20 was used as the ultraviolet absorber in [Example 3]
A sunlight exposure test similar to that in Example 3 was conducted using Ubinul N-35 (substituted acrylonitrino(c) manufactured by General Aniline) in place of 1, and as a result, similar effects were obtained.

[Example 11] A comparative experiment was carried out in the same manner as in [Example 2] except that nitrocellulose was used instead of superbetscasite 1126 in the resin composition, and as a result, similar effects were obtained.

[Example 12] A comparative experiment was conducted in the same manner as in [Example 2] except that ethyl cellulose was used in place of superbetskasite 1126 in the resin composition, and as a result, similar effects were obtained.

Claims (1)

[Scope of Claims] 1. In a color electrophotography method in which a color image is obtained by developing a latent image corresponding to a color separation image with color toner, a step of forming a color image using color toner on an image support; After the forming step, a step of developing the color image with a resin toner that does not contain a colorant on the color image;
A color electrophotographic method comprising the step of fixing a surface resin toner and a color toner on the image support. 2. In a color electrophotographic method in which a color image is obtained by developing a latent image corresponding to a color separation image with color toner, a step of forming a color image with color toner on an image support, and a step of forming the color image after this color image forming step. A step of developing the image support with a resin toner containing no colorant but an ultraviolet absorber, and a step of fixing the surface resin toner and color toner on the image support. Features color electrophotography.