| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming system that suppresses an increase in number of signal lines between an image forming apparatus and optional units, and alleviates communication load. <P>SOLUTION: The image forming system includes an image forming apparatus and one or more optional units removably attached to the image forming apparatus. The image forming apparatus transmits a specifying command for specifying an identifier and an instruction command for instructing operation to all of the optional units by outputting the commands on a single common signal line. Each optional unit outputs acknowledgement status on a single common signal line in a case where an identifier appended to the instruction command is the same as an acquired identifier. If the identifiers are different, on the other hand, each optional unit outputs a value indicating whether it itself is currently performing an operation in response to acknowledgement status transmitted by another optional unit. <P>COPYRIGHT: (C)2008,JPO&INPIT |
