| 摘要 |
PURPOSE:To ensure to detect a jam by a method wherein a relationship between the signal of a hole detector provided for the passage of a recording paper feed hole and the paper feed signal is measured. CONSTITUTION:Paper feed tractors 2, 3 are driven synchronously with a pulse motor 4. A feed detector 5 is disposed close to a finish terminal of the paper feed tractor 2. A flip flop 11 is set with the command signal 21 of the pulse motor 4, that is reset by the feed hole detecting signal of the feed detector 5. Normally the detecting signal 22 delays to the extent of a constant time T, and the value of a counter 13 may not exceed a given value N. Whenever a paper is not fed properly, the command signal 21 enters into the flip flop 11, where the detecting signal 22 may not enter into the flip flop 11 even if the time T has elapsed. Accordingly, the detecting signal is delayed, causing the counter 13 not to be reset within a permissible time and the value of the counter 13 exceeds N value resulting in giving a jam detecting signal. |
