Patent ID: 7627273

Claim:
A developing unit, comprising: a plurality of container main bodies, each of which comprises a development roller; a plurality of toner supply members, each of which comprises a toner supply port and supplies toner to each of the plurality of container main bodies; a drive mechanism configured to move the toner supply members so that each toner supply member can be positioned at a toner supply position at which the toner supply port is positioned inside the container main body, and at a retraction position at which the toner supply member is positioned outside the container main body; a position holding mechanism configured to restrict the movement of each toner supply member when the toner supply member is positioned at the toner supply position; and a retraction mechanism configured to release the toner supply member from the position holding mechanism and position the toner supply member at the retraction position when an electric power is cut off when the toner supply member is positioned at the toner supply position.