Patent ID: 7720418

Claim:
A developing device comprising: a developing unit; a toner cartridge that is detachably arranged in parallel with the developing unit, the toner cartridge supplying toner to the developing unit; and an opening that is disposed between the developing unit and the toner cartridge, through which the toner passes, for supplying the toner to the developing unit and discharging toner from the developing unit to the toner cartridge, wherein the developing unit includes a developer carrier that develops a latent image on an image carrier with toner, a conveying paddle that supplies the toner from the toner cartridge to the developer carrier, and a first control valve disposed adjacent to the opening, the first control valve having a moving part disposed such that in a first position the moving part is in an undeformed state and contacts the conveying paddle, and in a second position the moving part is elastically deformed toward the opening, and a supporting part, fixedly attached at the opening and supporting the moving part, and wherein the conveying paddle contacts the moving part while rotating and elastically deforms the moving part toward the opening, such that toner is discharged from the developing unit into the toner cartridge through the opening.