An apparatus for discharging waste toner, including a housing temporarily storing waste toner separated from a surface of a photosensitive medium; a waste toner discharge port formed at a bottom of the housing; a shutter rotatably disposed at a side of the housing to open and cover the waste toner discharge port; a pinion gear to rotate the shutter; and a fixed gear, disposed on a frame to which the housing is mounted, engaging the pinion gear, the pinion gear rotating along the fixed gear when the housing is mounted to the frame, to rotate the shutter away from the waste toner discharge port. The shutter includes a latch to hold the shutter in place when the shutter covers the waste toner discharge port.