| 摘要 |
PURPOSE:To expose a no-image area of a photosensitive body securely by providing a light source for exposing the photosensitive body differently from image exposure where the optical path of the image exposure is not impeded in the lengthwise direction of the photosensitive body. CONSTITUTION:The photosensitive drum 1 is rotatable around an axis X and has an area S where sharp-cut exposure is performed and image areas G1-G3 which are exposed to an original image through a slit by use of an image forming lens 9; the image area G1 is where an image of a maximum usable original is projected and the image areas G2 and G3 are where the original image is projected in reduction mode. The light source 8a for sharp-cut exposure, and light sources 8b and 8c for black blind exposure are provided and the light source 8a is turned on throughout image formation. When the light source 8c is turned on when the projection area of the original image is G2 and the light sources 8b and 8c are turned on when the projection area is G3, discharging the area on the photosensitive body 1 where development need not to be performed. |
