| 摘要 |
PURPOSE:To prevent the deviation in superposition between respective color images and to obtain a color image having high quality by maintaing the relative positions among a photosensitive drum, an optical scanning means and a transfer drum always at a specified relation. CONSTITUTION:A photosensitive drum 12 and a transfer drum 19 are driven by a gear G1 of the photosensitive drum and a gear G2 of the transfer drum which are turned by a driving motor 23 via a driving gear G1, etc. when a copying botton is operated. A semicircular gear G62 and a forward driving gear G7 in the positions where the engagement therewith starts drive first both drums 12, 19 and at the same time a pulley 26 is rotated by a motor 23, G62, G7 and a revolving shaft 25, by which an optical scanning means is moved. A semicircular gear G63 and a backward moving gear G8 are meshed with each other at the same instant when the G62 and G7 are disengaged from each other. The G7 is rotated counterclockwise by change gears G10, G11, by which the pulley 26 is rotated reversely and the scanning means returns to the position where the scanning is started. The gear ratio of G10, G11 is made to 1:2, by which the return stroke of the scanning means is made to twice faster than the forward stroke. The drums 12, 19 make one turn in one forward and backward travel of the scanning means, by which the respective relative positions are maintained always at a specified relation. |
