Developing device

A developing device comprising:

• a developing unit;
• a toner cartridge mountable on or detachable from the developing unit and comprising:
• a casing defining an internal space for accommodating a developing agent and formed with a communication hole for supplying the developing agent to the developing unit, and
• a shutter movable between an open position in which the communication hole is open and a closed position in which the communication hole is closed;
• a shutter drive member including a first gear that extends in the moving direction of the shutter and that has a rotational axis extending in an axial direction, the shutter drive member being engageable with the shutter to be movable together with the shutter when the toner cartridge is mounted on the developing unit;
• and
• a second gear meshingly engageable with the first gear to transmit a drive force to the first gear, the first gear being disengaged from the second gear when the shutter is in at least one of the open position and the closed position,
• wherein the shutter drive member is configured to be urged in a direction intersecting the axial direction to bring the first gear that has been disengaged from the second gear into contact with the second gear.