Patent ID: 8544983
Filing Date: 2013-10-01
Classification: B41J

Abstract:
1. An image forming apparatus comprising: a recording head having a nozzle surface in which nozzles to eject liquid droplets in a horizontal direction or a direction slanted from the horizontal direction are formed, the nozzle surface being disposed in a vertical direction or a direction slanted from the vertical direction; a head tank to supply liquid to the recording head; a suction cap to cap the nozzle surface of the recording head; a suction member connected to the suction cap to suck out liquid from the nozzles by the suction cap; a valve member to open or close a sealed space formed by capping the nozzle surface with the suction cap to atmosphere; a liquid supplier to supply the liquid to the head tank and return the liquid from the head tank; and a control unit to control servicing of the recording head, the control unit causing the suction cap to cap the nozzle surface and the suction member to be driven so as to suck out liquid from the nozzles, the liquid supplier to supply the liquid so as to pressurize the head tank after the suction of liquid, the valve member to open the sealed space to atmosphere, the suction member to discharge liquid remaining in the suction cap after opening the sealed space to atmosphere, the liquid supplier to return the liquid from the head tank so as to form negative pressure in the head tank after the discharge of liquid, and the suction cap to be removed from the nozzle surface after the formation of negative pressure; a wiper to wipe off the nozzle surface of the recording head; and a moving mechanism to move the wiper to wipe off the nozzle surface of the recording head from top to bottom, wherein liquid droplets not used for image formation are ejected from the nozzles in conjunction with movement of the wiper, the nozzle surface comprises multiple sections, and an amount of liquid droplets not used for image formation and preliminary ejected from the nozzles is set for each section, with an amount of liquid preliminarily ejected from the nozzles disposed in a lower section is greater than an amount of liquid preliminarily ejected from the nozzles disposed in an upper section.