Developing Cartridge Including Rotary Member Having Detectable Extending Portions for Determining Presence of the Developing Cartridge

A developing cartridge is provided. The developing cartridge includes a housing which accommodates developer therein, a receiving member provided which couples with a force output member of an image forming apparatus to receive a driving force, a developing roller which rotates by the driving force received by the receiving member; a detectable rotary member having a first detectable portion and a second detectable portion and rotates by the driving force from a first rotational position where the first detectable portion is detected by a detection member provided in the image forming apparatus to a second rotational position where the second detectable portion is detected by the detection member, and a cut-off mechanism which cuts off a transmission of the driving force from the receiving member to the detectable rotary member in a state where the detectable rotary member is positioned in the second rational position.