Patent ID: 7463837

Claim:
An image forming apparatus for forming a first toner image with a dark toner and a second toner image with a light toner and superposing said first toner image and said second toner image on a sheet for thereby outputting an image, said image forming apparatus comprising: a first developing unit storing the dark toner; a dark toner replenishing device for replenishing the dark toner to said first developing unit; a second developing unit storing the light toner; a light toner replenishing device for replenishing the light toner to said second developing unit; and a toner replenishment control unit for controlling operations of said dark toner replenishing device and said light toner replenishing device; wherein said toner replenishment control unit stores a replenishment history of the light toner and a replenishment history of the dark toner and corrects, at the time of replenishment of the light toner, a light toner replenishing operation by referencing said replenishment history of said dark toner to thereby control the operation of said light toner replenishing device or corrects, at the time of replenishment of said dark toner, a dark toner replenishing operation by referencing said replenishment history of said light toner to thereby control the operation of said dark toner replenishing device.