Developing cartridge and process unit

A developing cartridge detachable from a photosensitive unit including a photosensitive drum and a pressing member, the developing cartridge comprising:

• a developing roller configured to rotate about a first axis extending in a first direction, the developing roller having a first side and a second side opposite to the first side in the first direction;
• a case including a first wall disposed at the first side of the developing roller and a second wall disposed at the second side of the developing roller;
• and
• a first arm configured to be supported by the first wall of the case and configured to swing between a first posture and a second posture about a second axis extending in the first direction, the first arm including a first protrusion projecting from the first arm in the first direction,
• wherein the first protrusion includes a first pressed part configured to receive a pressing force from the pressing member, and
• wherein, in a state in which the developing cartridge is attached to the photosensitive unit and the photosensitive drum contacts the developing roller, the first arm is configured to take the first posture in which the developing roller is pressed against the photosensitive drum by the pressing force applied to the first pressed part from the pressing member, and the second posture in which the first pressed part is released from being pressed by the pressing member.