| 摘要 |
PURPOSE:To correct an image formation position by detecting the quantity of the position shift of a form by an optical detector nearby a register roller and storing it, and controlling supply time and the movement of a lens block for power variation according to the difference from the quantity of the shift when the form is supplied again. CONSTITUTION:When a form P is supplied, light emitting elements 131 and 135 and photodetecting elements 132 and 136 detect and store the quantities lx1 and ly1 of position shifts. Similarly, the quantities lx2 and ly2 of position shifts of a next form are detected to calculate errors Ex=lx1-lx2 and Ey=ly2-ly1. Then, the lens block 8 for power variation is driven on the basis of the Ex to correct the X-directional shift. When a unimagnification copy is made, the movement extent of the lens block 8 is Ex/2. Further, the operation time of the register roller 17 is varied on the basis of the Ey to correct the (y)-directional position shift. Thus, the position shift is corrected in this constitu tion and the image having good quality is obtained. |
