Patent ID: 7684715

Claim:
An image forming apparatus comprising: an image bearing member; a developing device including a developing unit for storing a developer containing toner and magnetic carrier, said developing device developing an electrostatic image formed on said image bearing member by using the toner; a toner replenisher for replenishing the toner to said developing device; a first controller for controlling a replenishing operation of said toner replenisher, based on information regarding a toner concentration in the developing unit; a sensor for detecting a concentration of a control patch formed by said developing device; and a second controller for controlling a correction operation for an image forming condition, based on a detection result of said sensor, wherein said second controller does not execute the correction operation for the image forming condition when the toner concentration in the developing unit is not within a predetermined range, and wherein said second controller executes the correction operation for the image forming condition when the toner concentration in the developing unit is within the predetermined range.