Gap Control System for Transported Paper Sheet with a Pair of Flat Belts.

A machine that transports paper sheet by using a pair of flat belts, handles various paper sheet with regard to size, thickness and texture. This often causes the gap between the sheets to change when it is transported over a long distance. If the gap becomes shorter than a certain threshold value, it causes sheet jam. We have therefore developed a gap control system that determines the transport distance of sheets and measures the gap change before the sheets reach the gap controller. Using thses information, it estimates the gap change after the gap controller and sets a target value. The contoller varies the transport velocity in an optimum pattern and controls the gap to the target value. We applied the system to a transport route and it reduced the standard deviation of gap into 2/3.