To discriminate the overlapped condition of sheets accurately at all times by adjusting properly the output value of a signal emitting element for sensing a double feed of sheets.
A sheet handling device with a function to sense a double feed of sheets includes a sheet feeding stacker 1 to admit placing of sheets thereon, a sheet feeding means to pay out the sheets on the stacker 1 to the specified position, the signal emitting element 6a and a signal receiving element 6b to sense the double feed of sheets located downstream of the sheet feeding means, for example in such a configuration that the wave transmitting element and the wave receiving element of an ultrasonic sensor are installed confronting with the sheets interposed, a sensitivity adjusting means 35 to adjust the output of the signal emitting element 6a through comparison of the sensing value of the signal receiving element 6b with the specified reference value, and a control means for a driving means to drive the sheet feeding means, wherein the sensitivity adjusting means 35 adjusts the output of the signal emitting element 6a in the condition that the driving means is stopped or decelerated to the specified speed. Thereby a specified output value is obtained at all times from the signal receiving element 6b, and stable sensing of double feed can be performed even if the sensibility is deteriorated resulting from the wave transmitting element and wave receiving element being influenced by the environmental temperature or other secular changes.
HIROSE SHUNICHI
YAMASHITA MASASHI
Koji Mizuno
Toshiro Nakamura
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