Image forming apparatus with superimposed dark and light toner images

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 dark toner and corrects, at the time of replenishment of the light toner, a light toner replenishing operation by referencing said replenishment history of the dark toner to thereby control the operation of said light toner replenishing device.

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 corrects, at the time of replenishment of the dark toner, a dark toner replenishing operation by referencing said replenishment history of the light toner to thereby control the operation of said dark toner replenishing device.