A developer cartridge may include a gear configured to be movable between an engagement position in which the gear engages an auger or supply gear to provide toner from a toner container to a developing unit and a disengaged position in which the gear does not engage the auger or supply gear. The gear may be moved by a cam and/or cam gear from the engagement position to the disengaged position and vice versa. The cam gear may include toothless and toothed portions to allow the developer cartridge to maintain the movable gear in either the engagement position or the disengaged position. In some arrangements, an urging member such as a spring may bias the cam gear in a rotation direction, while a lever may provide a counteracting force when the movable gear is to be maintained in a particular position.