A waste-sludge discharging unit is provided to discharge waste sludge being removed by a cleaning blade from an image carrier. The waste-sludge discharging unit has a waste-sludge receiver to receive waste sludge gravitating from the image carrier. The waste-sludge receiver has an outlet on one side of a bottom thereof. A blade pushes the waste sludge accumulated on the bottom of the waste-sludge receiver toward the outlet. A blade mover operates the blade. The blade operates in contact with the bottom of the waste-sludge receiver only when being moved toward the outlet.