| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect double-feed even when a variety of sheets are fed. SOLUTION: In a paper feeder, an optical double-feed sensor 120 detects a double-feed in which two or more sheets of paper are fed overlappingly with each other in a paper conveying passage through which stacked sheets of paper should be fed one by one. An ultrasonic double-feed sensor 122 detects a double-feed by the principle of detection different from that of the optical double-feed sensor 120 in the paper conveying passage. A detectability determination part 106 determines whether or not the sheet fed to the paper conveying passage can be detected for double feeding by the optical double-feed sensor 120. A double-feed detection control part 108 makes the ultrasonic double-feed sensor 122 detect the double-feed of the sheet when the sheet fed to the paper conveying passage cannot be detected for double-feeding by the optical double-feed sensor 120. COPYRIGHT: (C)2008,JPO&INPIT
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