Patent attributes
A cartridge includes; a first gear rotatably provided at the casing; a second gear including a toothed portion and a toothless portion; and a storing portion configured to store the second gear. The second gear includes an arm that is flexible and extends substantially along a peripheral direction of the second gear. An inner peripheral surface of the storing portion includes a bulging portion that bulges inward in a radial direction. The bulging portion has a peak portion closest to a rotation center of the second gear. The arm is deflected while the arm contacts the bulging portion. The deflection of the arm is changed from an increasing tendency to a decreasing tendency at the peak portion as a base point. The toothed portion of the second gear is separated from the first gear when the end portion of the arm has crossed over the peak portion.