| 摘要 |
An image forming apparatus reducing number of control signals in detecting nth connection stage of a paper feed cassette unit piled up, and increases noise resistance. It includes a main body part and a paper feed cassette unit that can be piled up in plural stages under main body part. Main body part has a start control line transmitting a start signal; a ready control line transmitting a ready signal; and a main body side control part generating start signal and detects nth connection stage of paper feed cassette unit on number of times of ready signal. Paper feed cassette unit has a cassette side control part delaying start signal inputted from an upper stage through start control line to output it to a lower stage, and while delaying start signal, generating a ready signal to output it toward ready control line to upper stage. |
