Speed fluctuations at a motor supplied with a two-phase current is reduced
by changing the current value ratio at each phase in the drive current to feed
a drive motor for an image reader to allow a light source lamp to move, free from
speed fluctuations, to scan at a constant scanning speed. The drive motor is supplied
with current different in value at each phase from constant current drive circuits,
which, in one embodiment, are connected with current regulating variable resistors.
An acceleration detector is fixed at the drive motor to detect acceleration fluctuations
in rotation of the drive motor to detect speed fluctuations. In some embodiments,
thermal control of the motor drive circuit is provided and vibration proofing to
isolate the light receptor from the drive motor.
