Spindle unit control method and image forming apparatus

摘要

A spindle unit control method controls a plurality of spindle units which rotate in synchronism with each other, and comprises with respect to each of the spindle units a first step of obtaining a phase error by comparing phases of a detection signal indicating a rotary reference position of the spindle unit and a first clock signal, a second step of generating a second clock signal having a phase which is adjusted by delaying or advancing the phase of the first clock signal by the phase error, and a third step of controlling the rotation of the spindle unit by a phase locked loop based on the detection signal and the second clock signal. The first clock signal is used in common with respect to each of the spindle units, and the second clock signal is independent for each of the spindle units.