Patent ID: 8787803

Claim:
A developing device comprising: a developing device main body, and a developer cartridge detachably mounted to said developing device main body and storing a developer, said developer cartridge comprising: a case member that stores said developer; a supplying opening provided on said case member, and a first shutter that opens and closes said supplying opening, said first shutter having a first engaging portion, said developing device main body comprising: a housing that stores said developer supplied by said developer cartridge; a receiving opening provided on said housing, and a second shutter that opens and closes said receiving opening, said second shutter having a second engaging portion, wherein, when said developer cartridge is mounted to said developing device main body, said first engaging portion engages said second engaging portion, wherein said housing of said developing device main body has a lock member that locks a movement of said second shutter, wherein, when said developer cartridge is mounted to said developing device main body, said first engaging portion engages said second engaging portion and also presses said lock member so that said lock member allows said second shutter to move, wherein said first shutter and said second shutter are configured to move in conjunction with each other by engagement between said first engaging portion and said second engaging portion.