| 摘要 |
<p>PURPOSE:To detect double feed reliably even of such paper as characters or figures are described by detecting the amount of permeated light continuously for predetermined time. CONSTITUTION:In case of double feed, the amount of permeated light is low when compared with single feed to reduce the collector current thus to increase the collector current accordingly. Since the predetermied detection level VR is set higher than single white sheet level but lower than single printing section level and double feed level, the collector voltage under double feed will be higher at anytime than the referential voltage VR irrespectively whether characters or figures are described. Consequently, H-level signal is produced continuously from the output terminal (c) of comparator 28 for predetermined time or over the detection period T for example. Upon receipt of said signal, control section 40 will decide double feeding and perform corresponding control.</p> |
