| 摘要 |
PURPOSE:To obtain the excellent picture quality without extended and contracted picture, by synchronizing a photoreceptor with a tractor of paper running based on a laser beam scanning, in an electrophotographic system taking the laser beam as an exposure light source. CONSTITUTION:The photoreceptor 5 is rotated with a photoreceptor driving DC motor 9. The rotation is detected with a photoreceptor rotation detecting tachometer 10. An output signal of a counter 8 of laser beam scanning is inputted as a reference input of a photoreceptor driving comparator 11, its input and the count of the tachometer are compared at the comparator 11, whether the speed of the motor 9 is adequate or not is discriminated, and a photoreceptor driving DC motor drive circuit 12 performs phase locked loop control so that the rotation of the photorecetor 5 has the same timing as the laser beam scanning. The photoreceptor and the tractor of paper running are synchronized based on the laser beam scanning, allowing to obtain the good picture quality without extended or shrinked picture. |
