| 摘要 |
PURPOSE:To record positive and negative images overlappingly, by making charging, negative exposure, charging in reversed polarity and positive charging on a photoreceptor providing a carrier transportation layer on a photoreceptor layer. CONSTITUTION:When a carrier transportation layer being an upper layer of photoreceptor is charged negatively, positive charges are collected at the boundary with the lower photo conductive layer (a). When negative charging is made with laser light, charges are discharged for the bright part through conducted photoreceptor (b). Next, positive charging is made for the surface of photoreceptor to cancell the negative charges of the dark part of negative exposure (c). Finally, an original image is exposed positively, the photo conductor layer is conducted for the bright part and the positive charges at the layer boundary to be discharged and the surface of photoreceptor is at positive potential. The bright part for negative and positive exposure is formed with a latent image of positive potential to the background. |
