Patent ID: 8422915

Claim:
A developing device of an image forming apparatus, comprising: a developing cartridge which has a mounting recess therein; a developer containing unit which contains developer therein, and which is replaceably disposed in the mounting recess of the developing cartridge to form a developer transfer path fluidly communicating with the developing cartridge; and a shutter unit which opens the developer transfer path when the developer containing unit is mounted in the developing cartridge, and which closes the developer transfer path when the developer containing unit is removed from the developing cartridge, the shutter unit being elastically biased in a direction which closes the developer transfer path, wherein the developer containing unit comprises a developer cartridge which contains both a quantity of developer to be supplied to the developing cartridge and waste developer discharged from the developing cartridge, and wherein the developer transfer path comprises a supply path, through which the quantity of developer is transferred from the developer cartridge to the developing cartridge, and a collecting path, through which the waste developer is transferred from the developing cartridge to the developer cartridge.