CARTRIDGE

PROBLEM TO BE SOLVED: To provide a cartridge capable of reducing wear of a protrusion to be detected.SOLUTION: A developing cartridge 7 is provided with a reset gear 50. On the reset gear 50, a protrusion to be detected 81 is disposed at a position separated from a rotational center thereof. The protrusion to be detected 81 is composed of an elastic body and protrudes from the reset gear 50 at a side of the developing cartridge 7 opposite to a housing 13 side thereof. A gear cover 43 is mounted to the housing 13. The gear cover 43 has an opposing portion 84 that is opposed with respect to the reset gear 50 from a side opposite to the housing 13. Further, the protrusion to be detected 81 is positioned under the following states: the protrusion to be detected 81 is positioned at an initial position prior to rotation of the reset gear 50; and the protrusion to be detected 81 is brought into contact with the gear cover 43 and is elastically deformed in the gear cover 43.