| 摘要 |
PROBLEM TO BE SOLVED: To lessen a processing load of a main body control unit in an image formation apparatus to which optional devices can be attached.SOLUTION: A main body control unit controls logic of a selection signal for selecting optional control units that serve as communication partners at an initial communication to sequentially select option control units of the option devices starting at a foremost stage as the communication partners, thereby recognizing the number of the option devices that are to be attached to an image formation apparatus. Thereafter, the main body control unit sets the logic of the selection signal to logic that means a non-selection state. Each of the option control units communicates with the main body control unit if the selection signal with the logic that means that the option device is selected as the communication partner, and determines what number the option device including the option control unit itself on the basis of history of the logic of previously input selection signals if the selection signal with the logic that means the non-selection state. |
