Patent ID: 7437102

Claim:
An image forming apparatus, comprising: a carrier on which an electrostatic latent image is formed; a plurality of development cartridges which develop the electrostatic latent image with toner to form a toner image; a rotary unit on which the developing cartridges are mounted around a rotational shaft of the rotary unit, and which rotates the developing cartridges about the rotational shaft so as to oppose any of the developing cartridges to the carrier; and a controller which controls a rotation of the rotary unit for switching the developing cartridges and a driving of the developing cartridges to form the toner image, wherein: the controller adjusts the toner stored in the developing cartridge for successively forming the image so as to invert the developing cartridges upside down by rotating the rotary unit based on image forming job information for executing an image formation; the image forming job information includes at least a job toner consumption amount required to execute the image forming job; the image forming job information includes a consumption amount of the toner stored in the developing cartridge which is positioned at a developing position opposed to the carrier; a margin consumption amount and a limit consumption amount are set; the limit consumption amount indicates that a toner amount stored in the developing cartridge is near end amount; the margin consumption amount indicates that the toner amount stored in the developing cartridge is a toner amount in which a little margin toner amount is added to the limit consumption amount; and when the job toner consumption amount is smaller than the limit consumption amount even when the job toner consumption amount exceeds the margin consumption amount, the controller completes the image forming job without performing an operation of adjusting the toner stored in the developing cartridge.