| 摘要 |
PURPOSE:To readily and accurately adjust the quantity of exposure light of a photoreceptor automatically by detecting part of the original exposure scanning light with an image sensor, comparing the same with a specified set voltage in a comparator and controlling the quantity of light emission of an original lighting lamp. CONSTITUTION:The original O is radiated by radiating light of an original lighting lamp 3-1. The exposure scanning light through reflection from the original O exposes a photosensitive drum 1 and part thereof is received in an image sensor 12. The maximum detection output voltage of this image sensor 12 is compared with the set voltage of a comparator 16 via signal processing circuit 15. This causes the quantity of the lamp 3-1 to be automatically adjusted by the comparison output outputted by the circuit 16 according to the maximum detection output voltage of the image sensor 12 corresponding to the intensity of the reflected light from the ground part of the original. As a result, the quantity of exposure light of the photoreceptor is automatically adjusted with ease and accuracy, whereby good quality images are formed. |
