| 摘要 |
<p>PURPOSE:To realize the accurate detection for the presence or absence of a faulty feed of the copy paper, by detecting the current or voltage for the copy discharge when the copy paper passes and deciding whether or not the copy paper passed through the copying point based on the result obtained through a comparison between the detected current or voltage and the reference value. CONSTITUTION:When the copy paper 3 reaches the copying point 4 with the prescribed timing, the discharged current value given from a discharge wire 8 of a copying corotron 6 which starts the discharge with the above-mentioned timing is reduced. At the same time, the potential of the wire 8 is set at a high level. This high level is compared with the reference voltage given from a reference voltage generator 11 through a comparator 12. The output Q of a D type FF14 is set at a low level with the output of a low level delivered from the comparator 12. Thus the fact that a copy paper 5 has passed through the point 4 is confirmed. In case the paper 5 does not reach the point 4 with the prescribed timing owing to the occurrence of a jam, a decision output showing the faulty feed of the copy paper with a high level of the output Q is produced after the discharge of copy is started. Thus a jam is detected. In such way, the accurate jam detection is always avalable with no malfunction due to the wear or the contamination.</p> |
