PAPER SHEET PROCESSOR

PROBLEM TO BE SOLVED: To accurately determine the number of residual paper sheets to improve operating efficiency of a device even when a detection sensor is erroneously attached or changed with time. SOLUTION: This paper sheet processor has: a detection sensor 41 detecting a position of an ascending backup plate 24; a detection lever sensor 36 detecting a position of a bill having reached a delivery position; a calculation means 43 calculating a detection time difference between the detection sensor 41 and the detection lever sensor 36; a measurement means 44 measuring a residual amount of the bills on the basis of the detection time difference calculated by the calculation means 43; a determination means 45 determining whether the residual amount measured by the measurement means 44 is not more than a prescribed amount or not by use of a reference threshold value; and a correction means 46 detecting the ascending backup plate 24 in a vacant state having no bill by the detection sensor 41 and the detection lever sensor 36, calculating the detection time difference, comparing the calculated detection time difference and a preset reference detection time difference for deciding the vacant backup plate, and correcting the reference threshold value on the basis of a time difference therebetween. COPYRIGHT: (C)2008,JPO&INPIT