PURPOSE: To prevent the wrinkle of a transfer material by slanting the lengthwise direction of a press-contacting part formed of a couple of rolls of a fixation device to which the front end part of the transfer material conveyed slantingly is delayed.

CONSTITUTION: The separation side of the transfer material P is restrained, so it is curved along a conveyance path as shown by an arrow (b). The nonseparation side, on the other hand, is separated from a drum 3 later than the separation side and held linear as shown by an arrow (c) and is clamped between fixing rolls 21 and 22 by l earlier than the front end (d) of the separaration side. Consequently, the transfer material P is conveyed slantingly to cause wrinkle. For this, purpose, the lengthwise direction of the press-contacting part of the fixing roll couple is slant by l to the direction perpendicular to the conveyance direction of the transfer material to clamp the front end of the slanting transfer material P uniformly between the fixing rolls 21 and 22. Consequently, fixation is performed while its front end is conveyed uniformly to the surface of the fixing rolls, so the wrinkle of the transfer material and a paper jam near the fixation device are prevented.