A motor controller includes DC motor, driving mechanism, voltage generator circuit
and control unit. The driving mechanism moves an object having a predetermined
mass against a load applied to the object and by transmitting a rotational force
of the motor to the object. The voltage generator circuit generates first and second
voltages. The first voltage is high enough to rotate the motor to such a degree
as to get the object moved by the driving mechanism. The second voltage has the
same polarity as the first voltage and has such amplitude as to prevent the motor
from rotating either in a backward direction due to a cogging torque or in a forward
direction. The control unit controls the voltage generator circuit in such a manner
that the voltage generator circuit applies the second voltage to the motor after
having applied the first voltage to the motor.
