Patent ID: 7773913

Claim:
An image forming apparatus comprising: a first image forming unit and a second image forming unit each including an image bearing member configured to bear an electrostatic image, a charging device configured to charge the image bearing member, and a development device configured to develop the electrostatic image with a developer including a mixture of toner and carrier; a transfer device configured to serially transfer toner images formed on the respective image bearing members of the first image forming unit and the second image forming unit onto a transfer medium, wherein the second image forming unit is disposed on a downstream side of the first image forming unit in a direction of travel of the transfer medium, and wherein each of the development devices of the first image forming unit and the second image forming unit is configured to recover a residual transfer toner remaining on each of the image bearing members; a replenishment device configured to replenish a replenishing developer including a mixture of toner and carrier to each of the development devices; and a discharge device configured to discharge the developer from each of the development devices, wherein a weight percent of carrier in the replenishing developer to be replenished to the development device of the second image forming unit is larger than a weight percent of carrier in the replenishing developer to be replenished to the development device of the first image forming unit.