| 摘要 |
PURPOSE:To control a copying magnification of an original by providing one piece of variable refractive power element on an image formation lens system, and providing a means for controlling a refractive power in the two-dimensional direction of the variable refractive element. CONSTITUTION:A prescribed copying magnification is inputted by an input device 20, and by controlling a lens barrel driving means 16, an image formation lens system is moved to a prescribed position in its optical axis direction. In accordance with information which is stored in advance, a voltage is applied to a piezoelectric body bimorph element, etc., and by varying a refractive power of a variable refractive power element 5-2, an optical path length is corrected so that an image surface of an image formation lens system 5 is positioned on a photosensitive drum 17. Next, an original platen driving means 12 and a drum driving means are controlled so that a speed ratio of a moving speed of an original platen 11 and a peripheral speed of the photosensitive drum 17 becomes equal to a variable power ratio, and an electrophotographic process is started by driving the original platen 11 and the photosensitive drum 17. |
