Patent ID: 8576504

Claim:
A driving apparatus comprising: a motor configured to drive a driven member, the motor including: a rotor having a cylindrical magnet whose outer circumferential surface is magnetized; a first yoke having a first magnetic pole portion which faces the outer circumferential surface of the cylindrical magnet; a second yoke having a second magnetic pole portion which faces the outer circumferential surface of the cylindrical magnet; a first coil configured to magnetize the first magnetic pole portion; a second coil configured to magnetize the second magnetic pole portion; a position detector configured to detect rotation position of the rotor; an open-loop driver configured to switch an energization state of the first coil and second coil at a predetermined time interval; a feedback driver configured to switch an energization state of the first coil and the second coil according to an output of the position detector; and a controller configured to switch the open-loop driver and the feedback driver at a predetermined driving speed, wherein the controller changes the predetermined driving speed according to the magnitude of the load acting on the motor.