Driving control apparatus for stepping motor and image forming apparatus

A driving control apparatus for driving a stepping motor by switching an excitation current supplied to a coil of a predetermined phase between a first excitation current value, a second excitation current value greater than the first excitation current value, and a third excitation current value still greater than the second excitation current value, the driving control apparatus comprising:

• a driving control unit that sequentially switches, for the supplied excitation current, at least the first through third excitation current values in a first mode for generating a first driving force by the stepping motor, and
• sequentially switches, for the supplied excitation current, the first and second excitation current values in a second mode for generating a second driving force smaller than the first driving force,
• wherein, in the second mode, the driving control unit sequentially switches the excitation current values at such timings that in a single cycle of driving with the excitation current, a time for which the second excitation current value is applied is longer than ¾ and shorter than 5/2 of a time for which the first excitation current value is applied.