MOTOR CONTROL DEVICE, AND OPTICAL SCANNING DEVICE, IMAGE FORMING DEVICE AND PRINTED CIRCUIT BOARD INCLUDING THE SAME

摘要

A CPU 1 determines that a motor is undergoing a forward rotation when a time difference between a detection timing of a light beam deflected by a rotating polygonal mirror and an output timing of a detection signal from a magnetic detector element 5 falls within a predetermined range, and that the motor is undergoing a reverse rotation when the time difference does not fall within the predetermined range. With this configuration, a detection circuit for detecting voltage induced in three phases is unnecessary, and therefore the cost can be reduced. Furthermore, there is no need to detect voltage induced in each of the three phases. As it suffices to simply detect the time difference, the amount of time required to detect a rotation direction can be reduced.