| 摘要 |
PURPOSE:To let the light source for exposure provide also a function of solid-black- preventing lamp by providing a shutter between the light source for exposure and original platen glass plate in the exposure system of the copying machine of original platen stationary system or optical system stationary system. CONSTITUTION:The shutter 2 provided between a light source 3 for exposure and original platen glass plate 1 moves by assuming the integral construction with the uniform-velocity optical system such as the light source 3 for exposure. The shutter 2 is positioned in the place 2a where it does not hamper the projection of the original scanning. At the reverse running and initial condition setting of the uniform- velocity optical system, it moves to the place 2b where it remains between the light source 3 for exposure and original platen glass plate 1 and hampers the projection of the original picture. The bottom surface of the shutter 2 projected to a photosensitive drum 11 in the position of 2b is constituted by, for example, a white diffusion reflecting surface. Thereby, the surface of the photosensitive drum 11 is radiated by sufficient light through a slit 10 without any solid-back preventing lamp to lower the potential of the photoreceptor surface, thus the unnecessary toner consumption in the developing process may be prevented. |
