PURPOSE: To realize a fresh image forming device which is capable of performing fixation by heating selectively only a part where a toner image is formed and also achromation of an achromatic toner image.

CONSTITUTION: An image forming device possesses a fixing device heating selectively a position of a toner image IT by a thermal head 41 through a heat-resistant belt 43 and fixing on a transfer sheet S and an achromatic lamp 42 performing achromation of an achromatic toner image in cooperation with selective heating of the position by the fixing device and is capable of performing selection between an image forming mode and achromatic mode and signal processing driving the thermal head is made to differ from each other by the image forming mode and achromatic mode.