Magnification is selected in response to selection of simplex or duplex mode. Then an original image is scanned by an optical system with the predetermined magnification and formed as an electrostatic latent image on a photoreceptor drum. Other latent images on the photoreceptor drum than the above mentioned electrostatic latent image, which correspond to a leading edge area and a rear edge area of the original image, are erased by an interimage eraser. Since toner does not adhere to the areas thus erased, toner is not transferred onto the leading and rear edge areas of the copy paper. Accordingly, when the transferred image on the copy paper is fixed by a fixing roller, the leading edge portion of the copy paper does not adhere to the roller and consequently, the copy paper can be prevented from winding around the roller.