An image forming apparatus includes a pre-fusing paper sheet guide, a fuser unit and a control section. The pre-fusing paper sheet guide is disposed adjacent to the fuser unit on its upstream side. The fuser unit includes a pressing roller having, an electrically conductive surface, a grounding structure grounding a pressing roller's surface, and a cleaning mechanism cleaning the pressing roller's surface. The cleaning mechanism includes a web and a take-up roller. The control section sets a winding quantity x of the web to 0.7 mm when a setting for printing without margin is not made, and sets the winding quantity x to 2.1 mm when the setting for printing without margin is made. If the number of sheets accumulated through the image forming process becomes not less than 18, the control section causes the take-up roller to wind the web by the winding quantity x, and performs an image forming process.