Patent ID: 7043171

Claim:
An image forming apparatus comprising: a developing device, which develops an electrostatic image formed on an image bearing member with developer including toner and carrier; a density sensor, which detects a density of the toner of the developer in said developing device; control means for controlling an amount of toner to be supplied to said developing device by comparing a value regarding the density of the toner obtained from said density sensor with a target value; prohibiting means for prohibiting an image forming operation when the value regarding the density of the toner obtained from said density sensor becomes equal to or less than an error level, the error level being a value smaller than the target value; changing means for changing the target value from a first target value to a second target value when the value regarding the density of the toner obtained from said density sensor becomes equal to or less than the error level, the first target value being the target value before the value regarding the density of the toner becomes equal to or less than the error level, and the second target value being smaller than the first target value and larger than the error level; and recovering means for performing a recovery operation by supplying toner based on the second target value changed by said changing means after said prohibiting means prohibits the image forming operation.