Limpness detecting device, limpness detecting method, and sheet handling apparatus including limpness detecting device

摘要

According to one embodiment, a limpness detecting device includes a transmitting unit to irradiate an acoustic wave towards a conveyed sheet to excite a Lamb wave, a first receiving unit to detect a leaky wave of the Lamb wave emitted from a front surface of the sheet, a second receiving unit to detect a leaky wave of the Lamb wave emitted from a back surface of the sheet, a comparison data calculating unit to calculate comparison data based on the signal detected by the first receiving unit and the signal detected by the second receiving unit, and an intactness judgment unit to compare the comparison data calculated by the comparison data calculating unit with a preset standard value and judge whether the sheet is an intact bill or not, based on a result of the comparison.