| 摘要 |
PURPOSE:To use the same projection lens with a copying system by using a long-sized line sensor 21 which is nearly as long as a photosensitive transfer drum is wide corresponding to a branch mirror. CONSTITUTION:A branch mirror 20 is inserted into the path of transmitted light projected on the photosensitive transfer drum 12 in the lengthwise direction of the drum 12, and the long-sized line sensor 21 is arranged along the branch mirror 20 in order to photodetect the reflected light. The branch mirror 20 uses, for example, a half-mirror, etc., and the light reflected by the mirror 11 of the copying system is split into two; when the branch mirror 20 uses the half-mirror, the transmitted light of the mirror 20 is guided to the photosensitive transfer drum 12 and also supplied to the long-sized line sensor 21. Thus, the same projection lens with the copying system is used. |
