Patent ID: 8629643

Claim:
An image forming apparatus, comprising: a stepping motor arranged in a conveying path for a paper on which an image is formed; a driver for driving the stepping motor; a current detecting unit for detecting an actual current value that is magnitude of a current at the driver for driving the stepping motor; and a control unit for providing, to the driver, a set current value for setting magnitude of a current to be supplied to the stepping motor, for every predetermined cycle, based on the actual current value, wherein the control unit includes a first determining portion for determining, as an estimated load torque value, a load torque value corresponding to the set current value in a previous cycle and the actual current value in a present cycle, by referring to a relationship between actual current and load torque of the stepping motor with respect to the set current value, a second determining portion for determining a target load torque value that indicates torque to be output by the stepping motor, based on the estimated load torque value, and a third determining portion for determining, as the set current value, a current value corresponding to the target load torque value, by referring to a relationship between maximum output torque of the stepping motor and current supplied to the stepping motor.