| 摘要 |
PURPOSE:To prevent uneven speeds of plural driving sources and to obtain high-quality images by subjecting the reference signal to control means for the speeds of the driving sources to frequency division according to the accuracy of the control means. CONSTITUTION:A common reference frequency signal FV is generated by a quartz oscillator 53 is supplied through a frequency divider 54 for drum control and a frequency divider 55 for belt control to respective PLL control parts 52. The PLL control parts 52 control rotations by comparing the signals divided down from the frequency signal FV and the frequency signal FG fed back thereto. The control without having the uneven rotations relative to each other is, therefore, possible without necessitating discrete provision of frequency generating means. Since the PLL control part for the drum dispenses with an encoder of the accuracy lower than the accuracy of an encoder for the belt, the number of using the high-accuracy encoders is decreased by providing the frequency divider to supply the reference frequency corresponding to the resolution of the encoders for the respective PLL control parts. |
