An image forming apparatus includes a recording head including heads containing arranged nozzles to discharge a droplet, the heads are arranged in a zigzag form along a nozzle array direction; a conveyer belt with suction holes to convey a printing medium in a direction intersecting a head array direction; and a control unit to control an blank discharging; wherein suction hole arrays including the suction holes arranged in the head array direction, are arranged at a predetermined interval; wherein one of the suction hole arrays is a reference suction hole array including the suction hole to pass a position facing the nozzle of a nozzle array end and the nozzle in an overlapping part of two heads in the nozzle array direction; and wherein the control unit makes each nozzle discharge a blank discharging droplet to the suction holes, using the reference suction hole array as a standard.