| 摘要 |
PURPOSE:To simplify the image forming optical system of a copying machine changing the image forming position on a photosensitive body according to copying magnification by moving leading-edge and trailing-edge light shielding members as required according to copying magnification. CONSTITUTION:As an image forming lens 3 moves in an optical axis direction according to copying magnification, the leading and trailing edges of an image on the photosensitive body 8 changed. In response to said change, a light shielding sheet winding roll 6 is turned and driven, and a leading-edge light shielding sheet provided with an L-shaped angle 4A of the prescribed bent part is moved according to magnification alone, while a trailing-edge light shielding sheet is moved according to magnification and copying sheet size. Thus, light is shield in the area where an original image is not projected. The image forming optical system is simplified because the lens 3 need not to be moved in a direction perpendicular to the optical axis according to copying magnification. |
