| 摘要 |
PURPOSE:To form an image of the tip part of an original at the same exposure start position without changing a placing position of the original by changing an original scanning speed, also displacing a plane mirror by a prescribed distance in a prescribed direction, and also displacing a lens in a specified direction, when changing a copying magnification to a variable magnification from an unmagnification. CONSTITUTION:At the time of an unmagnification, a lens 6 and a plane mirror 52 are both at a position of a full line, and a carrying speed of an original O and a moving speed of the surface of a photosensitive body are both V. When switching a copying magnification to beta(not equal to 1) from an unmagnification, a carrying speed of the original O is changed to V/beta. Also, the lens 6 and the plane mirror 52 are displaced to a position of a broken line in accordance with the magnification beta. That is to say, the plane mirror 52 is displaced by a prescribed distance in the direction orthogonal to the mirror surface or in the direction inclined by a prescribed angle against the mirror surface, and also the lens 6 is displaced so that its displacement components in the optical axis direction and in the direction orthogonal to the optical axis become to have a prescribed size (not equal to 0), respectively. |
