fixation motor fm are controlled to be always constant further the motor control circuit 22c controls the rotation and stoppage of the transportation rollers 33 the resist rollers 39 and the separation roller 32 by controlling the clutches 221 222 and 223 referring to fig1 and 4 one of the features of the copying machine is an improvement in which the cut sheet transported through the bypass transportation path d4 is prevented from being biased with respect to the transportation direction of the cut sheet or from being biasedly transported the prevention of biasing of the cut sheet is achieved as will be later described by setting the rotational circumferential speed of the resist rollers 39 the first roller slightly lower than that of the transportation rollers 33 the second roller another feature of this embodiment is that the offset of a toner image to be transferred onto a cut sheet is prevented which is caused by vibration of the cut sheet due to fluctuation in the load to the transportation rollers 33 the load fluctuation is caused by a sudden removal of the tensile force which has been applied to the cut sheet when the tail edge of the cut sheet transported through the bypass transportation path d4 departs from the resist rollers 39 the prevention of the image offset on the cut sheet is also achieved by controlling the circumferential speed of the resist rollers 39 more specific explanation will be given to the rotation control of the photoreceptor drum 20 the transportation rollers 33.