IMAGE FORMING APPARATUS AND PROGRAM

PROBLEM TO BE SOLVED: To provide an image forming apparatus that hardly causes changes in magnification of an image to be formed, even when a recording material having a thickness larger than a predetermined thickness is used.SOLUTION: The image forming apparatus includes: toner image forming means forming a toner image; transfer means transferring the toner image onto a sheet by using a photoreceptor drum 11; a fixing unit 20 fixing the toner image to the sheet by using a heating roll 21; and a control unit 500 controlling rotational speeds of the photoreceptor drum 11 and the heating roll 21. The control unit 500 controls a line velocity on the surface of the heating roll 21 to be faster than a line velocity of the photoreceptor drum 11 when a sheet of a predetermined thickness is used, and after at least a top end of the sheet in the conveyance direction of the sheet reaches the heating roll 21, the control unit continuously decreases the line velocity on the surface of the photoreceptor drum 11.