| 摘要 |
PURPOSE:To cause a peripheral speed of a photosensitive drum to exactly follow the scanning speed of an optical system, by using a pulse signal obtained by detecting an encoder corresponding to the scanning speed as a reference input, and a pulse signal obtained by detecting the binary discrimination mark of the drum as a feedback signal. CONSTITUTION:A linear type optical system encoder 5 provided in the scanning route of an optical system 4 is detected with a photosensor 11, and the obtained pulse signal is fed to a phase comparator 14 as a reference input. The output of this comparator 14 is amplified with a power amplifier 15 to drive a drive motor 16, and to rotate a photosensitive drum 7. Binary discrimination marks 12 are detected with a photosensor 8, and this pulse signal is fed back to the comparator 14, thus permitting the peripheral speed of the drum 7 to exactly follow the scanning speed of the optical system 4. |
