Patent ID: 7010237

Claim:
An image forming apparatus comprising: developing means for developing a latent image on an image bearing member using a developer containing a toner and a carrier; detecting means for detecting a density of a detection reference toner image; and control means for controlling a toner replenishment operation for replenishing said developing means, based on a detection result obtained by said detecting means, wherein, when the detection result obtained by said detecting means is equal to or smaller than a predetermined value, said control means performs a process, in a residual toner amount determination mode, wherein the process includes: a toner replenishment step of replenishing toner; a detection step of detecting the density of the detection reference toner image using said detecting means, and a comparison step of comparing a first detection result obtained in the detection step with a second detection result obtained by said detecting means before the toner replenishment step is performed an initial time, and for which repetitive performance of the steps is enabled while an image forming operation is halted, wherein, based on the results obtained in the comparison step, said control means determines whether the residual toner amount determination mode should be continued, and wherein, when in the comparison step the first detection result is greater than a value obtained by adding a predetermined amount to the second detection result, the control means determines that the residual toner amount determination mode should be terminated.