Patent ID: 7920799

Claim:
An image forming apparatus, comprising: a photoconductor to have an electrostatic latent image formed thereon; a developing device for developing the electrostatic latent image with a toner; a toner replenishing device for replenishing the toner into the developing device; and a controller for controlling an image developing operation by the developing device and a toner replenishing operation by the toner replenishing device, wherein the controller executes a non-replenishment mode for causing the developing device to perform image development without being replenished with the toner from the toner replenishing device, a discharge mode, following the non-replenishment mode, for discharging the toner remaining in the developing device and a refill mode, following the discharge mode, for refilling the toner into the developing device by the toner replenishing device, and the controller includes a dot counter for counting the dot number of an image to be printed and estimates an amount of the toner used for image development by the developing device based on the dot number at the time of image formation during the execution of the non-replenishment mode upon transferring from the non-replenishment mode to the discharge mode.