JPS6337374B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative-positive color reversal image forming method for obtaining positive color from negative color by electrophotography.

Conventionally, silver halide photography has been a common method for reversing negative colors to positive colors. However, it has the disadvantage that the processing time is long and the equipment is large-scale. Recently, methods have been proposed to solve these conventional drawbacks. In this method, colored transparent particles are electrostatically deposited in almost a single layer on the surface of a charged electrophotographic photoreceptor, and after exposure to a negative color image, particles whose electrostatic attraction with the photoreceptor has been weakened or removed are removed to form a particle image. In this method, the particle image is transferred to a blackbody or mirror-like image receptor, and then the image receptor is irradiated with white light to obtain a positive color image. This method has the characteristics of short processing time and compact equipment, but in order to obtain a bright and clear positive color image on the screen, a white light source with high illuminance is required.
It had the drawback of poor light efficiency.

The object of the invention therefore relates to an improvement of the above-mentioned conventional method. Specifically, it is an object of the present invention to provide a negative-positive color reversal image forming method for obtaining a bright and clear positive color image. That is, the gist of the present invention is
The object of the present invention is to improve the conventional drawbacks by changing the black body or mirror image receptor disclosed in the conventional method to a transparent image receptor.

Transparent image receptors that can be used in the present invention include, for example, cellulose diacetate, cellulose triacetate, acrylic, plastic films such as polyethylene terephthalate, single glass, or one side of the image receptor, such as polymer electrolytes, tin oxide, etc. A transparent conductor such as copper iodide that has been subjected to conductive treatment is provided. Further, if necessary, the image receptor may be provided with a conventional transparent adhesive layer such as vinyl acetate resin or butyl rubber coated on the surface receiving the particle image.

Next, one embodiment of the present invention will be described in detail based on the drawings.

First, a mixture of electrically conductive colored transparent particles, each colored red, green, and bluish-purple obtained by a conventional method and subjected to conductive treatment, is prepared. The shape of the particles used here is preferably spherical because it provides an excellent filling rate when arranged in approximately one layer on an electrophotographic photoreceptor, which will be described later.
Further, the specific resistance of the particles is preferably 10 ⁹ Ω·cm or less in view of the excellent resolution of particle images during development. In addition, it is desirable that the difference in specific resistance be within 10 ² Ω·cm for better mixing of particles. Further, the particle size is preferably 5 to 8 microns, since the resulting image is highly dense and has little fog.

Next, as shown in FIG. 1, an electrophotographic photoreceptor 3 comprising a conductive substrate 1 and a photoconductor layer 2 is charged and photosensitized in a dark place using, for example, a corona charger 4. Here, the electrophotographic photoreceptor that can be used in the present invention may be any ordinary one, and is not limited by the composition and structure of the conductive substrate and photoconductor layer.
Next, as shown in FIG. 2, the particles 6 are scattered on the surface of the photoreceptor 3 by a particle scatterer 5, and the particles are electrostatically attached by electrostatic induction due to the charge on the photoreceptor, and excess particles are removed, for example. Remove with mechanical force,
The particles are arranged in approximately one layer on the surface of the photoreceptor.

Next, as shown in FIG. 3, image exposure is performed through a color negative film 7, for example. Then, of the particles existing in the portion corresponding to the red (R) of the negative, only the charges on the photoreceptor immediately below the red particles are optically attenuated, while the charges immediately below the green particles and the blue-violet particles remain as they are. Therefore, there will be a difference in electrostatic attraction between the particles and the photoreceptor. Similarly, in the part corresponding to magenta (M) of a color negative, the particles are yellow (Y).
In , the particle, and in Black (Bl), the particle,
, are each held attached to the photoreceptor by strong electrostatic attraction.

Next, as shown in FIG. 4, the photoreceptor light 3 is vibrated by, for example, an electromagnetic vibrator 8, and particles whose electrostatic attraction with the photoreceptor has been weakened or removed are removed and developed.
In addition to mechanically vibrating the photoreceptor as described above, the developing means may include electrostatic development, development by the flow pressure of a highly insulating liquid, development by the wind pressure of gas, electric field development, and the like.

Next, as shown in FIG. 5, the particle image obtained in FIG. 4 is transferred to the transparent image receptor 9 described above. Here, as a transfer method for obtaining a permanent visible image, an image receptor having an adhesive layer is used, and the particle image is pressed in close contact with the particle image and transferred by an adhesive means. In addition, transfer methods for storing images for a short period of time and repeatedly using the image receptor include a method in which a pre-charged image receptor surface and a particle image are brought into close contact and transferred electrostatically, or a method in which a particle image is transferred between the image receptor and the particle image. There is a method in which the image receptor is brought into close contact with the image receptor, and then the image receptor is charged with, for example, a corona charger and electrostatically transferred. At this time, it is preferable to perform electrostatic transfer after exposing the entire surface of the photoreceptor having the particle image to remove the electrostatic attraction between the particles and the photoreceptor, since the transfer efficiency of the particles is good. Further, when performing electrostatic transfer, it is preferable to use an image receptor whose one side is conductively treated. Further, the particle image transferred to the image receptor can be removed by scraping it off with, for example, an ordinary conductive fur brush or doctor.

Next, as shown in FIG. 6, by irradiating white light from the particle image surface or the back surface of the image receptor 9 and observing the scattered light from the particles from the white light transmission side,
A negative-positive inverted color image is obtained. It is important to adjust the angle of incidence so that the white light irradiated here does not directly enter the viewer's eyes.

As explained above, the method for forming a negative-positive color reversal image of the present invention involves transferring a particle image obtained by development on an electrophotographic photoreceptor to a transparent image receptor and irradiating it with white light. Compared to black body or mirror-like image receptors, the loss of the amount of irradiated light on the image receptor can be significantly reduced. Therefore, there is an effect that a brighter and clearer color image can be obtained compared to the conventional method.

Examples of the present invention will be described below.

Example 1 First, red, green, and blue-purple solutions were prepared according to the following formulations.

(1) Red solution binder Sumitex Resin M-3 (manufactured by Sumitomo Chemical Co., Ltd.) 100 parts by weight Curing accelerator Sumitex Accelerator
EPX (manufactured by Sumitomo Chemical Co., Ltd.) 8 parts by weight Colored dye Methyl Orange 2 Eisen Rose Bengal B (manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight Water 100 (2) Green solution Sumitex Resin M- 3 100 parts by weight Sumitex Accelerator EPX 8 Colored dye Suminol Leveling Yellow NR (manufactured by Sumitomo Chemical Co., Ltd.) 10 parts by weight Kayacion Green A-4G (Nippon Kayaku Co., Ltd.)
7 parts by weight Water 100 (3) Blue-violet solution Sumitex Resin M-3 100 parts by weight Sumitex Accelerator EPX 8 Colored dye Kayacion Turquis Blue P-GF (manufactured by Nippon Kayaku Co., Ltd.) 10 Weight part Assist Violet 6B (Hodogaya Chemical Industry)
(manufactured by Co., Ltd.) 1.2 parts by weight water 100 The solutions (1) to (3) above were separately granulated using a spray dryer to obtain colored transparent particles with a particle size of 5 microns to 80 microns.

Next, 100 parts by weight of the above-mentioned mixture of colored transparent particles was coated with 100 parts by weight of a conductive solution having the following formulation on the particle surface using a fluidized fluid dryer to obtain conductive colored transparent particles. The specific resistance of the particles obtained is 10 ⁴
It was Ω・cm.

Low resistance agent Copper iodide 2 parts by weight Binder Polyvinyl acetate 0.2 〃 Solvent Acetonitrile 100 〃 Next, a photoconductive solution with the following formulation was applied to aluminum vapor-deposited paper, and the total color sensitivity of the photosensitive layer was approximately 20 microns thick. A zinc oxide photosensitive paper was prepared.

Photoconductive substance Zinc oxide SAZETX 2000 (manufactured by Sakai Chemical Industries, Ltd.) 100 parts by weight Binder Acridik 6-1036 (manufactured by Dainippon Ink Chemical Industries, Ltd.) 20 parts by weight Sensitizer Sorapuyuairo 8G ( Sumitomo Chemical Co., Ltd.
(manufactured by Mitsubishi Chemical Industries, Ltd.) 0.5 parts by weight Eisen Rose Bengal B 0.01 Alizarin Cyanine Green GWA (manufactured by Mitsubishi Chemical Industries, Ltd.) 0.02 parts by weight Methanol 6 Toluene 100 The above solution was sufficiently dispersed and mixed using an attritor to obtain a photoconductive solution.

Next, the zinc oxide photosensitive paper obtained above was negatively charged in a dark place using a corona charger with an applied voltage of -6KV to -7KV. Next, the red, green, and blue-violet conductive colored transparent particles obtained above are classified into 20 microns to 32 microns, and the particles obtained by mixing equal weights are sprinkled on the photosensitive paper, and the excess particles are shaken off. When dropped, the particles adhered to the surface of the photosensitive paper by electrostatic induction and were packed in almost one layer and almost densely packed. Next, a 35 mm color negative film was used as an original and imagewise exposed for 5 seconds using a 500 W tungsten lamp as the light source. When the photosensitive paper was vibrated after image exposure, the exposed particles whose electrostatic attraction with the photosensitive paper was weakened or removed were shaken off, and a color-separated particle image was obtained on the photosensitive paper. Next, a transparent image receptor sheet made of cellulose triacetate coated with butyl rubber to a thickness of several microns as an adhesive layer was pressed tightly against the particle image and peeled off, and almost 100% of the particles were transferred to the adhesive layer of the sheet. It was done. Next, the incident angle of white light is
When the surface with the particle image was irradiated at 30 degrees and the scattered light from the particles was viewed from the white light transmission side in a direction perpendicular to the sheet, a bright clear positive color image with negative-positive inversion was obtained. It was done.

Example 2 After a transparent acrylic image receptor sheet was closely attached to the particle image obtained by development in Example 1, the front and rear sheets were positively charged with a corona charger with an applied voltage of +8 to +9 KV and then peeled off. The sheet has particles of approx.
80% electrostatically transferred. Next, white light was irradiated onto the sheet containing the particle image at an incident angle of 45°, and when the scattered light from the particles was observed in a direction perpendicular to the sheet from the side through which the white light was transmitted, the negative and positive images were reversed. A clear positive color image was obtained. After viewing, scrape off the particles on the sheet with a squeegee,
When images were repeatedly formed using the above procedure, approx.
Images could be obtained by repeating 200 times.

[Brief explanation of the drawing]

1 to 6 are views showing the principle of particle image formation in the negative-positive color reversal image forming method according to the present invention. 3... Electrophotographic photoreceptor, 4... Corona charger,
6... Conductive colored transparent particles, 8... Electromagnetic vibrator,
9...Transparent image receptor.

Claims (1)

[Claims] 1. At least three non-photosensitive conductive colored transparent particles colored in a color selected from the three primary colors of each additive coloring method.
A group of particles consisting of a mixture of types is electrostatically deposited in almost a single layer on the surface of a charged electrophotographic photoreceptor, and after exposure to a negative color image, particles whose electrostatic attraction with the photoreceptor has been weakened or removed are removed. Obtain a particle image, transfer the particle image to a transparent image receptor, and then irradiate the image receptor with white light from the back side to obtain a positive color image on the surface of the particle image by light scattered from the particles. Characteristic negative-positive color reversal image forming method. 2. The negative-positive color reversal image forming method according to claim 1, wherein the conductive colored transparent particles have a specific resistance of 10 ⁹ Ω·cm or less.