| 摘要 |
<p>PURPOSE:To obtain a stable jam detecting device which eliminates erroneous operation which can cope with the use of toners of various colors by installing a jam judging period setting means in a jam detecting device. CONSTITUTION:When a developer except a black one is detected by a color detecting means 19, a jam judging period setting means 20 sets a jam judging period T1, and also a period T2 for not judged a jam, based on the size and the travel starting position of a transfer material S detected by a transfer material size detecting means 17 and a pair of resist rollers 10. And, when the output of a reflection type photo-sensor 2 is changed from small to large during the period T1, a detecting device 1 judges it a jam by a transfer material, and stops a sensitive body 5 and the pair of resist rollers 10. Also, even if the output of the sensor 2 is changed from small to large during the period T2, the device 1 does not make a jam judgment and, accordingly, the sensitive body 5 and the pair of resist rollers 10 are not stopped.</p> |
