| 摘要 |
PURPOSE:To obtain high-quality images rapidly irrespective of kinds of originals by changing the quantity of corona application to change the potential curve of latent images and at the same time changing exposure and developing bias value by preset values according to the kinds of originals. CONSTITUTION:According to originals of different kinds, such as an ordinary original (a) having dark color images on white-color ground, such an original (b) which has colors on the background of the ordinary original and produces photographic fogs in the copied images, or an original (f) which is thin in image part, coronas are applied to a photoreceptor 1 with a DC corona discharger 2 and an AC corona discharger 3, and after the exposure of the original, latent images are formed by the irradiation over the entire surface with a lamp 4. At this time, the potential is detected with a potential sensor 10 and the exposure and developing bias having been set in relation to the quantity of applied coronas and the potential curve are applied by a control part to the photoreceptor 1 so as to conform to the potential curve of the reference potential of either of the potential for the black color original or the potential for the white color original depending upon the kinds of originals. In this way, always sharp images are made obtainable. |
