| 摘要 |
PURPOSE:To prevent lowering of dark potential of a photosensitive body and to obtain a good image free from uneven density by uniformly exposing said body to light of <=700nm wavelength after end of an electrostatic latent image forming step. CONSTITUTION:Remarkable dark decay phenomenon of potential is observed as shown in the graph (b) when a tungsten lamp contg. IR rays is used as a light source and a photosensitive body is exposed to a prescribed illumination in a test for examining an effect of uniform exposure on the dark decay of potential. Presumably, this phenomenon is caused by the following reasons: Since the absorption coefft. of the a-Si photosensitive body is lowered with short wavelength light, and paired electrons-holes are formed in the comparatively inner part of the a-Si layer, electrons left in the inside fall down in the capture level and form space potential. As a result, the dark potential decay is remarkably improved by using light of <=700nm comparatively short wavelength for uniform exposing light. Accordingly, the dark lowering phenomenon can be prevented without lowering contrast in the dark, and a good image free from uneven density can be obtained. |
