Patent ID: 7596340

Claim:
A developer cartridge for supplying a toner-containing developer and for removable mounting on one of a plurality of developing units that are disposed along a rotating outer peripheral surface of a developing unit main body, the developer cartridge comprising: a developer containing portion that contains the developer supplied to a developing unit; a developer recovery portion, disposed at one end of the developer containing portion in a longitudinal direction, that recovers a used developer from the developing unit; a supply port that opens to supply the developer from the developer containing portion to the developing unit; a recovery port that opens in the developer recovery portion to recover the used and recovered developer from the developing unit; and an opening and closing member, fitted around the outer circumferential of the developer containing portion and the developer recovery portion, that opens or closes the supply port and the recovery port, wherein the developer containing portion is formed slender at an end portion close to the developer recovery portion and linked to the developer recovery portion.