Patent ID: 7218870

Claim:
An image forming apparatus, comprising: image forming means for forming an electrostatic image on an image bearing member; developing apparatus for collecting a developer including a toner and a carrier, and developing said electrostatic image; developer density detecting means for detecting a density of the developer inside the developing apparatus; image density detecting means for detecting a density of a developed image developed by said developing apparatus; environment detecting means for detecting a state of the environment in which the apparatus itself is placed; developer replenishing means for replenishing a replenishment developer including at least the toner for said developing apparatus; and control means for performing: a replenishing operation capable of controlling a replenishing operation of said developer replenishing means based on a result of detecting by said image density detecting means a developed image which develops a replenishing control electrostatic image formed on said image bearing member by said developing apparatus, and an image density control for controlling an electrostatic image forming condition of said image forming means based on the result of detecting by said image density detecting means a developed image which develops an image density control electrostatic image formed on said image bearing member by said developing apparatus; wherein, in case a result of detecting by said environment detecting means is changed by more than a predetermined value or said replenishment developer is renewed, said control means advances to a mode of performing said image density control, while performing a replenishing operation by said developer replenishing means not depending on a result detected by said image density detecting means, but based on a result of detecting by said developer density detecting means.