To correctly detect the number of copies of a ribbon even when the ribbon is exchanged.

Information 110 corresponding to serial numbers is recorded in copying screen in reference of an ink ribbon for an image printer. The information 110 corresponds to the number of copying sheets linked from a first one screen formed in the ribbon, and this is stored as a bar code of (n) bits. Inasmuch as the number of printing sheets or sheers of the remains can be detected only by reading the bar code, even when the ink ribbon is exchanged, the number of printing sheets or remaining sheets can be detected correctly after the exchange, and it can be displayed.