Patent ID: 6970656

Claim:
An image forming apparatus for being loaded with a cartridge in an exchangeable manner, and for image forming to a recording sheet with expendable material contained in said cartridge, said image forming apparatus comprising: a writer, operated if it is detected that an estimated used amount of said expendable material has become equal to or more than a predetermined value according to checking of said estimated used amount, for writing shortage information of shortage of said expendable material to a memory; a checking unit, operated upon setting of said cartridge in an apparatus main unit, for checking whether said memory stores said shortage information; a controller for allowing said image forming before removal of said cartridge from said apparatus main unit even after said writer writes said shortage information to said memory, and for, after said removal of said cartridge, driving said checking unit again upon setting of said cartridge in said apparatus main unit, said controller inhibiting said image forming if it is detected that said memory stores said shortage information.