| 摘要 |
PROBLEM TO BE SOLVED: To precisely control the service life of accumulated use amount by providing a memory with a plurality of storage areas and writing use information obtained in a previously decided order every time that the use information is obtained. SOLUTION: In the memory 20, a plurality of storage area, for example, three areas A1-A3 for writing the use information of a process cartridge 3 are prepared. Then, a writing is executed in turn like the first writing is normally executed in the area A1 and the next writing is executed in the area A2. Thus, the continuous use information is stored in the memory 20. By a CPU 30, the values of the area A1-A3 are read out. Based on the size relation and difference (continuity) among three pieces of use information, it is decided whether three pieces of written use information are wrong or not. The discontinuous information among the use information in three storage areas is decided to be wrong and the correct use information is restored from two pieces of left continuous use information. |
