Patent ID: 7738819

Claim:
An image forming apparatus, comprising: an image bearing member configured to bear an electrostatic image thereon; and a developing device configured to develop the electrostatic image with a toner to form a toner image on the image bearing member, wherein the developing device includes a developing unit configured to develop the electrostatic image, the developing unit including a hopper configured to temporarily store toner supplied from a toner cartridge to the developing unit, and a first rotating member to form a first space in the toner supplied to the developing unit, and the toner cartridge configured to contain the toner and supply the toner to the developing unit through at least one opening, the toner cartridge including a second rotating member to form a second space in the toner contained in the toner cartridge, wherein the developing device circulates the toner contained in the toner cartridge with the toner supplied to the developing unit when the second rotating member presses part of the toner contained in the toner cartridge into the first space formed in the developing unit by the first rotating member while the second rotating member presses the part of the toner contained in the toner cartridge, and the first rotating member presses part of the toner supplied to the developing unit into the second space formed in the toner cartridge by the second rotating member while the first rotating member presses the part of the toner supplied to the developing unit, and wherein the developing device satisfies the following relationship: T H >T C wherein T H represents an internal temperature of the hopper, and T C represents an internal temperature of the toner cartridge.