Patent ID: 7623801

Claim:
An image forming apparatus comprising: a toner cartridge storing a toner; an image forming unit which forms a toner image with the toner supplied from the toner cartridge; a counter which counts a consumption of the toner in the toner cartridge; and a controller which makes judgment on necessity of a correction of a count value counted by the counter when a density of a first toner image formed by the image forming unit is lower than a first density previously defined in correspondence to the first toner image based on a quantity of the toner in the toner cartridge indicated by the count value of the counter and index information which indicates a status of the apparatus, and which corrects the count value of the counter when determining the correction of the count value to be necessary, wherein the controller uses a detected density of a second toner image as the index information, the second toner image formed by the image forming unit where an operation parameter affecting the image density is set to a different value from the value used in the formation of the first toner image, and the controller determines the correction of the count value to be necessary if a residual quantity of the toner in the toner cartridge indicated by the count value is smaller than a predetermined quantity and the second toner image has a higher density than a second predetermined density.