| 摘要 |
PURPOSE:To reduce the error of variable power setting by comparing the size of an image read by a signal of a solid-state image pickup element with a signal of the size of a preliminarily set transfer paper. CONSTITUTION:A mirror 7 on an optical path is switched while describing a sector to lead the light to a photosensitive body 8 or a solid-state image pickup element 9, and optical path lengths of them are equalized. The projection light is made incident on the element 9, and a linear index image a1 corresponding to the magnification at this time is projected onto the element 9, and a controller reads this position and compares it with the position of a linear index image a2 on the transfer paper which is preliminarily set and stored. If positions a1 and a2 are different from each other, a motor drives a lens 4 and mirrors 5 and 6 to perform the loop control, and varying of the magnification is terminated to start the copying operation when two positions coincide with each other. Thus, the variable power is set in accordance with a ratio of the size of the original to that of the transfer paper, and the solid-state image pickup element is used to perform the loop control, and the variable power control with less error is possible. |
