Patent ID: 8270855

Claim:
An image forming apparatus which can detachably mount a cartridge that includes at least an image bearing member configured to bear a toner image and a toner forming unit configured to form the toner image on the image bearing member therewith, the image forming apparatus comprising: a rotatable intermediate transfer belt; a first cartridge which includes at least a first image bearing member configured to bear a toner image and a first toner forming unit configured to form the toner image on the first image bearing member; a second cartridge which includes at least a second image bearing member configured to bear a toner image and a second toner forming unit configured to form the toner image on the second image bearing member; a control unit configured to control the first toner forming unit and the second toner forming unit to control a toner amount per unit area of a toner image corresponding to a maximum density image respectively formed on the first image bearing member and the second image bearing member, wherein the toner image from the second image bearing member is transferred onto the toner image transferred from the first image bearing member to the intermediate transfer belt, and the toner images superposed on the intermediate transfer belt is transferred to a transfer material; and a detection unit configured to detect a measure of consumption of the second cartridge, and wherein the control unit controls, when the measure of consumption detected by the detection unit is a second measure of consumption which is in a consumed state more than a first measure of consumption, the first toner forming unit and the second toner forming unit so that a difference in a toner amount, acquired by subtracting the toner amount per unit area of the toner image corresponding to the maximum density image formed on the first image bearing member from the toner amount per unit area of the toner image corresponding to the maximum density image formed on the second image bearing member, becomes greater than a difference between the toner amounts those of when a detected measure of consumption is the first measure of consumption.