| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively, easily and accurately discriminate whether a process cartridge is new or old without mounting parts such as a storing element and a transmitter in the process cartridge. SOLUTION: By providing a toner residual amount detection circuit 220 detecting toner residual amount in a developing device 50 and a cartridge capacity detection circuit 700 detecting the usage of a photoreceptor, and by storing toner residual amount detection information, photoreceptor usage information and the number of printed sheets in the storing element 230 of a device main body 310, whether the cartridge is new or old is discriminated based on the toner residual amount detection information and the photoreceptor usage information. |
