Patent ID: 8422908

Claim:
A developing device to be attached to and detached from a main body of an electrophotographic image forming apparatus, the developing device comprising: a housing that defines a toner storage area to store toner and a developing portion having a developing roller, the housing includes an opening that defines a toner supply window to connect the toner storage area to the developing portion, a pair of rails disposed adjacent to the toner supply window and extending in an end-to-end lengthwise direction of the developing roller, an insertion hole on an outer surface of the housing corresponding to a location of the pair of rails, and a securing portion formed on an outer surface thereof; and a blocking member including a blocking portion configured such that the toner supply window is open when the blocking member is removed from the pair of rails and the toner supply window is closed when the blocking member is inserted in the pair of rails from an outside of the housing, the blocking member including a bent portion extending from the blocking portion and configured to be removably secured in the securing portion of the housing.