SU996985A1 - Method of producing full color electrophotographic picture on organic semiconductor layers - Google Patents

Description

The invention relates to electrophotography and can be used to produce multi-color slides and microfilms by electrophotography.

A known method of producing a multicolor electrophotographic image on organic Photo-semiconductor layers, including the sequential formation of the image of Each color by layer charging, exposure and the appearance of the hidden image Cl3.

The disadvantage of this method is the low image quality due to the influence of the previous manifestation on the formation of a food image.

The purpose of the invention is to improve the quality of a multi-color image by eliminating the influence of the previous appearance on the subsequent image formation. .

This goal is achieved by the fact that according to the method of obtaining a multicolor electrophotographic image on organic photo semiconductor layers, including sequential formation of the image of each color by charging the layer.

exposing and developing the latent image after exposing the first color image, the layer is heated to 40-70 ° C for 0.5-5 min, the subsequent cooling to cc is 1hatnoy temperature and the layer is discharged to zero potential, after which an image is formed second color, then the layer is discharged,

10 is heated and exhibits a first color image.

In this case, the second layer is charged to the uroyN 25-40% of the first charge, a. In both cases, the layer is discharged by a corona charge of opposite polarity.

The essence of the proposed method is that first two charge images are formed,

20, the first of the KOTOJSJXs can be preserved by polarizing the organic layer at the temperature and cooling it, and only after that the second image of the second color is shown, and then the first image of the first color is revealed by heating and developed by the first color. colors.

FIG. 1-10 schematically show the 3D sequence of operations for obtaining a multicolor image using the proposed method. The proposed method consists of the following basic operations: charging of an organic photo semiconductor layer; exposing the first color image, heating the layer; cooling the layer and its discharge to zero potential; secondary charge layer; exposing a second color image; the extension of the charge image by the second color producer; discharge of the layer to zero potential; heating the bed; the appearance of the detected charge image by the first color producer. The charge of the organic photo semiconductor layer, for example, on the basis of a poly-N epoxy propyl carbazole, is carried out in a corona discharge to the operating potential. FIG. Figure 1 shows a uniform charge by a negative charge of a layer consisting of an organic photo semiconductor 1 and an electrically conductive base 2. After that, an image of the first color is exposed and a charge image is formed on the layer (Fig. 2). Then the organic layer is heated to 40-70 ° C. L is kept for 0.5-5 mi. In charged areas, under the action of an electric field surface charge, the dipole molecules are oriented and a positive bound charge is formed at the surface (Fig. 3) The charge image is an electric double layer consisting of surface charge and charge of opposite polarity. Keeping the layer for a certain time at an elevated temperature is necessary for orienting dipole molecules, segments and other full-length groups with a large time constant. At low temperatures and short times, dipole molecules are not oriented, and at high temperatures, the discharge of the layer in the dark has a negative effect. Since the polarization effect (the magnitude of the resulting bound charge) is proportional to the intensity of the electric field of the charge image, the primary charge of the layer should be made to high potentials. To preserve the orientation of the dipole molecules, the organic photosemiconductor layer is cooled to room temperature. After the layer is cooled, the oriented dipole molecules in the layer are frozen — and the created image in the form of an electrical double layer can last for several hours. Due to the fact that the density of the bound charges usually does not exceed 25-40% of the density of the free surface charge of the initial charge image, it is necessary to remove free charges from the surface of the layer that are not compensated by the bound charges, and for this purpose the layer is discharged to zero potential, for example, by deposition of charges of opposite polarity (positive) corona discharge (Fig. 4). After that, a second cycle of formation of a new charge image is performed, i.e. The layer is recharged by charges of the primary polarity (Fig. 5) to a potential, the value of which is 25-40% of the value of the charging potential of the first cycle. The latter is connected with the necessity of obtaining equal contrasts of the first and second images. Next, an image of the second color is exposed (Fig. 6), and the resulting charge image is developed by positively charged particles of the second color developer (Fig. 7, area 3). In order to eliminate surface charges that are not compensated by the charges of the particles of the developer, the layer is discharged to zero potential (Fig. 8) by deposition of charges of opposite corona discharge or uniform illumination of the layer. Then heating the layer to 40-70s The QQ charge image of the first color is detected conserved within 0.5–5 min (Fig. 9). At elevated temperatures, the oriented dipole molecules can be rotated again, they are disoriented, and the associated charge is destroyed. s exhibit a positive particles of the developer of the second color (FIG. 10, region 4). In those places that reappear, the particles of the second developer are superimposed on top of the particles of the first developer (Fig. 10, area 5). Thus, the proposed method allows to obtain a three-color image consisting of two pure colors and one mixed. In this case, the influence of the first appearance on the formation of a second-color charge image is excluded. An experimental verification of the method was carried out on organic photo semiconductor layers consisting of a glass substrate with a transparent conductive underlayer of tin dioxide, over which a layer of 5 µm thick was applied made of polyH-epoxypropylcarbazole sensitized with 5 mol% trinitrofluorenone. The layer was charged with a scorotron to a potential of 450 volts and set to the exposure and heating positions. The image of the color-separated original was projected with a decrease of 6 through the lens. Then the heater was turned on, the temperature of the bed was maintained; 40-70 ° C for 0.5-5 minutes. Then, the heater was turned off, the layer was cooled to room temperature, and the scorotron was discharged with a positive charge. After that, the layer was recharged with negative charge up to - (100-180) and exposed to a second-color flower-like original. The formation of the obtained charge relief was carried out by a device for the liquid manifestation of the meniscus type. The developer of the blue lacquer core K particle dispersed in the dielectric liquid freon — 113, concentration b g / l. The potential of the counter electrode 50c. After the blue developer developed, the layer was placed in the heating position where it was held for 0.5-5 min at 40-70 s. The detected first-time charged relief pattern showed a red color containing red lacquer varnish particles dispersed in freon 113. The potential of the counter electrode is 30 V. The spectral optical density of the red and blue colors in the absorption region: was:; 0.8-1.5, black g; 0.6-1.2. The overlapping of colors on each other is absent. The resolution of images in both red and blue is 100 lines / mm; it is limited by the optical system used. When the heating temperature is less than 40 ° C and more, the spectral optical density of the generated image decreases. The optical density is also reduced when the heating time is less than 0.5 minutes. . The proposed method is effective for obtaining good quality two color and three color images on organic photo semiconductor layers and can be used for the production of microfilms and transparencies. The technical and economic efficiency of the proposed method relative to the basic object is to improve the quality of the finished product. The method provides a multicolor image with bright saturated colors by eliminating the overlapping of colors on each other. The use of harmful substances is excluded.

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Claims (2)

. substances - washing liquid with solvents. An additional positive effect is that, due to the lack of developed images, exposure can be performed from the front side of the organic layer. This eliminates the transmission of defects of the bases or substrates to the electro-graphic image. For the practical implementation of obtaining multi-color images according to the proposed method, no additional devices or equipment are needed, one can be content with a combination of already available and used for these purposes. Claim 1. Intake a multi-color electrophotographic image on organic photo-semiconductor layers, including sequentially forming an image of each color by charging a layer, exposing and developing a latent image, characterized in that, in order to improve the image quality by eliminating the effect of the previous image after the exposure of the first color image, the layer is heated to 40–70 ° C for 0.5–5 min, after uyuschee cooling to room temperature and discharge DKU layer potentsiosha to zero, after which a second color image is formed, then a layer zhayut discharge heated and exhibit a first color image. 2. A method according to claim 1, characterized in that the layer is re-charged to a level of 25-40% of the first charge, and the discharge of the layer in both cases is produced by a corona charge of the opposite polarity. Sources of information taken into account during the examination 1. M. Anzai, Mori I. Color copying by liquid-development electrofax met-. hod.- Hitachi Hyorpn, 1974, v. 56, 6, p. 527-542 (prototype). Г® ф I Q Q  4- -I- .5 j® WG I Q Q I . four ®. ® r A e I Fig.T HHJ.I (rig. in fUt.9 FIG. ten