| 摘要 |
A paper multi-feed detection apparatus and a paper multi-feed detection method are provided for preventing the detection capability from being deteriorated by a noise factor and improving the detection precision even where an area around the feeding path has no extra space in terms of the shape and there are many noise-generating factors because of a demand for a smaller size of the device. An ultrasonic transmission opening formed in one of two feeding guide plates is large so as to discharge outside a reflected wave which returns through the ultrasonic transmission opening, and an ultrasonic receiving opening formed in the other feeding guide plate is smaller than a receiving face area of a receiver for receiving the ultrasonic wave.
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