| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problems in conventional ones, wherein, although a means for detecting a change in an output value according to variations in an ambient environment and arrangement of a device is provided, and the detected result is reflected on a threshold to accurately determine the double feed of a recording material, a dedicated correction operation is required for setting a threshold to determine the double feed and calculating a correction coefficient of the ambient environment, and productivity is reduced due to the control operation. <P>SOLUTION: A recording material determination device obtains a difference between a peak time, which is a first measurement result when an ultrasonic wave has passed through a recording material, and a peak time, which is a second or subsequent measurement result. The recording material determination device performs the comparison with a double feed determination threshold set based on the difference between the peak times, to accurately determine double feed of the recording materials without being affected by an environment and the kind of the recording material. <P>COPYRIGHT: (C)2013,JPO&INPIT |
