SU947810A1 - Method of producing electrophotographic image on dielectric film - Google Patents

Description

The invention relates to the field of reproduction technology by electrophotographic methods and can be used to obtain tone and line images mainly on films.

There is a method of electrophotographic image acquisition on a dielectric film by bringing the film into contact with a charged and exposed electrophotographic layer, completely compensating the latent image field by simultaneously depositing positive and negative ions on the film, irradiating the layer with an actinic light source and subsequent developing and drying of the image [1].

The disadvantage of this method is the presence of the so-called edge effect on images containing wide solid sections. The use of, in particular, a flat electrode during the development of the layer contributes to a decrease in the edge effect. However, with liquid manifestation, the complete elimination of the edge effect can be achieved only if the electrode is located from the film with a latent image at distances equal to approximately the film thickness, which is usually 10–50 μm. The location of the electrode at such small distances from the large format wafers is an almost impossible task, as well as the delivery and change of the developer in such gaps.

Another disadvantage of this method is the inability to obtain multiple images without re-shooting the original.

The purpose of the invention is the complete elimination of the edge effect when reproducing images containing solid sections of any size, as well as obtaining several images on films after a single reproduction of the original.

The goal is achieved in that, after the operation of full compensation of the latent image field produced from the separation films _f latent image on the selenium layer under safelight illumination. As a result of the separation of the film from the layer, the magnitude of the field strength above the middle and the edges of the continuous section increases and becomes the same. This makes it possible to reproduce, during development, solid sections with uniform density and regardless of their size. Since the film is separated under non-actinic illumination, the latent image on the selenium layer is retained. This 5 allows you to repeat the above image acquisition operation until, as a result of dark discharge, the layer potential drops below an acceptable level 10. Hidden images obtained on films can be displayed on either side, as well as on both sides.

The method is illustrated in figures 1-6. ,5

Figure 1 shows an electrophotographic layer 1 deposited on a metal substrate 2, bearing a positive latent electrostatic image 3; in Fig. 2 ', the same layer ^ c in contact with the film 4. In Fig. 3a, the operation of compensating the charge field of the latent image 3 by positive and negative ions 5 from the ion source 6, is presented;

radioactive type; in Fig. 3b, the operation of compensating the field of charges of a latent image <3 by positive and negative ions 5 from a source of 6 ions with a sliding discharge.

Figure 4 shows a film 4 with a latent image 7 separated from layer 1 and an electrophotographic layer 1 on a substrate 2 with a latent image

3. FIG. 5 shows the operation of developing a latent image 7 on a film 4 by particles of an electrographic developer 8 supplied from the device 9; figure 6 - the finished image 10 on the film 4.

Example 1. A line-art positive positive is reproduced with an optical image density of 1.45 and a background of 0.15 on a Pyloris electrophotographic apparatus. 45 Selenium plate with a layer thickness of about 50 μm is positively charged to a potential of 100 V and then exposed for 60 s with a diaphragm of 1:22. The exposed plate is transferred to a room with non-actinic lighting, where a sheet of a triacetate film with a thickness of 25 μm is applied to the layer in the vacuum frame. After reaching full contact of the film with the entire surface of the layer above the last, at a distance of 30 mm, a radioisotope static electricity neutralizer of the type NSE-400A is placed, the body of which is connected to the substrate _ selenium layer. Irradiation of the film on a layer of neutralizer spend 510 s. A film with a latent image is separated from the layer under non-actinic illumination and the outer side of the film is doused with a liquid electrographic developer for 5-10 s.

The result is a positive image of the original with uniformly developed alloy sections.

PRI me R 2. When the appearance of a veil, the body of the Converter is isolated from the substrate layer. The stroke original is reproduced in the same way as in Example 1, but the developer is supplied to both sides of the film by immersing the latter in a vertical metal cuvette. As a result, a positive image of the original is obtained on both sides of the film without an edge effect in continuous areas.

Example 3. A tone original is reproduced with a set of optical densities from 0.15 to 1.50 in the same way as in examples 1 and 2, but with a shutter speed of 10-15 s. As a result, an image is obtained with a satisfactory tone reproduction in the range of densities from 0.15 to 1.2 liters with no edge effect.

Using the proposed method of electrophotographic image acquisition provides, in comparison with existing methods, the ability to repeatedly reproduce bar and tone images by shooting the original once with uniform reproduction of solid portions of the image.

Claims (1)

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