| 摘要 |
PURPOSE:To form always a superior image, by changing over development bias potential when the same photoreceptor is exposed to the lights from 2 kinds of images to form a synthetic image using positive originals, and when an image is formed by exposure to only one light image. CONSTITUTION:Photoreceptor 1 is exposed to light from positive original 1 and when the second exposure to OFT or laser beams 7, bias potential of developing unit 8 is set to VDB2 approximate to the background potential. When only either of both the exposures is carried out, exposure quantity of the background is about half of that in the case of 2 time exposure, so the background potential is raised. As a result, the bias potential is changed over to potential VDB1 near the background potential having high potential. |
