A method for the color correction of an image component in the development of an electrophotographic printing

摘要

1,231,846. Electro-photographic developing. FUJI SHASHIN FILM K. K. April 30, 1968, [May 22, 1967], No.20531/68. Heading G2H. A latent electrostatic image formed on a photoconductive insulating layer having a conductive support is developed by forming a second latent image of the same polarity on an insulating layer having a conductive backing closely spacing the two latent images and electrically connecting the two conductors, and feeding a developer between the latent images, to obtain a developed image of the first latent image, the toner density of which is controlled by the second latent image. In one embodiment, shown in Fig. 1, a latent image 3 on photo-conductive layer 1 on conductive support 2 is placed near latent image 6 on insulating layer 4 on conductive backing 5, the conductors 4 and 5 are earthed, toner is introduced between the latent images, and adheres at areas 32 of latent images 3, a reduced amount adhering at area 31 due to the field produced by area 61 of latent image 6. In a reversal development embodiment Fig. 2 (not shown) the toner polarity is the same as that of the latent image (7) on the photo-conductive layer, and toner is deposited on the latent image under the influence of the second latent image. Multi-colour electrophotographs may be produced by the method, the first and second latent images being colour separated electrostatic images, produced for example by exposing a multi-colour transparency through filters, the toner colour corresponding to the first latent image, and the second image controlling the deposition of toner to obtain colour correction.