Cartridge having rotatable coupler

A cartridge, comprising:

• a rotatable member including at least one of a photosensitive drum, a developing roller, or an agitator;
• and
• a coupler to rotate the rotatable member by receiving rotation power from an external source, the coupler including:
• a rotatable coupler body including first and second slots spaced apart from one another by 180 degrees,
• a first coupler arm, provided in the first slot, to push and rotate the coupler body when the coupler receives the rotation power, the first coupler arm being movable to a first position and a second position of the first slot, the first position of the first slot being farther from an axis of rotation of the coupler body than the second position of the first slot in a radial direction with respect to the axis of rotation,
• a second coupler arm, provided in the second slot, to push and rotate the coupler body when the coupler receives the rotation power, the second coupler arm being movable to a first position and a second position of the second slot, the first position of the second slot being farther from the axis of rotation than the second position of the second slot in the radial direction with respect to the axis of rotation, and an elastic member to apply an elastic force to the first and second coupler arms in the radial direction.

A cartridge, comprising:

• a shaft;
• a first coupler body including a slot;
• a coupler arm, provided at the first coupler body, movable along the slot to a first position, a second position, and a third position, the first position being farther from an axis of rotation of the first coupler body than the second position in a radial direction with respect to the axis of rotation, and when the coupler arm is at the third position, the coupler arm is in contact with a wall of the slot that faces a rotation direction of the first coupler body and is prevented from being moved to the second position;
• an elastic member connected to the first coupler body to apply an elastic force to the coupler arm in the radial direction;
• a second coupler body coaxially connected to the first coupler body and to the shaft;
• and
• a connection part to connect the first coupler body with the second coupler body such that the first coupler body is rotatable by a predetermined amount without causing rotation of the second coupler body.