It is desirable to reduce disturbance of an unfixed toner image by
suppressing vibration of the trailing end of a recording medium, and to
thereby stabilize the quality of a formed image. In a first control time
period based on the leading edge of the recording medium as a reference,
a driving unit is controlled in accordance with detection of a loop. On
the other hand, in a control time period after the first control time
period, a target speed is determined from a drive speed of the driving
unit in the first control time period, and the driving unit is controlled
by the determined target speed.