| 摘要 |
PURPOSE:To correct scanning distortion and to improve precision by providing a means which varies an image scanning clock frequency continuously approximately to the scanning speed curve of a scanning spot formed through an optical deflector. CONSTITUTION:A light beam emitted by a light source 1 is passed through a condenser lens 2 and deflected by the optical deflector 4 composed of a polygon mirror to form a spot image on the surface of a photosensitive drum 3. A photodetector 5 generates a synchronizing signal by detecting the deflected light beam. A signal processing circuit 6 applies an information signal to a semiconductor laser driving circuit 7, and its timing is controlled with the synchronizing signal from the photodetector 5. The driving circuit 7 drives the laser 1 with the information signal from the circuit 6. The image scanning clock frequency for transferring the information signal applied to the driving circuit 7 is varied continuously in proportion to the scanning speed of the light beam scanning on the drum 3 to correct the scanning distortion.
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