Method of and device for detecting displacement of paper sheets

A displacement detection method for detecting displacement of paper sheets in transit, comprising the steps of:

• (a) detecting a leading edge of each paper sheet at a predetermined location along a conveyance line of conveyance belts for conveying the paper sheets;
• (b) detecting, after elapse of a predetermined time t.sub.1 following the detection of a leading edge of each paper sheet, the distance between one side edge of the paper sheet and a reference line set up along the conveyance line;
• (c) generating signals in response to said leading edge detecting and said distance detecting steps;
• and
• (d) measuring a passage interval, inclination (.alpha.), and lateral shift (Y.sub.0) of each paper sheet in transit in accordance with said signals.

A displacement detection device for detecting the displacement of paper sheets in transit along a conveyor, comprising:

• (a) sensing means for sensing the leading edge of the paper sheet in question;
• (b) displacement detecting means provided downstream of said sensing means at a predetermined distance spaced apart from said sensing means for detecting the conveyance state of the paper sheets;
• (c) the positions of the sensing means and the displacement detection means being spaced apart by a predetermined length and a detecting portion of said displacement detection means ranging from one edge of said conveyor to a predetermined distance so as to include a maximum shift of the paper sheets to be detected and to measure the lateral shift and skew of the paper sheets in transit;
• (d) a signal processing unit connected to said sensing means and said displacement detection means for driving same so as to detect the passage of the paper sheets;
• and
• (c) a microprocessor having a CPU, and memories and connected to said signal processing unit for performing various calculations for determining a passing interval, inclination, and lateral shift of the paper sheets in accordance with detected signals from said sensing means and displacement detection means.