Calibrating system for measuring thickness of pile of paper sheets by making measurements on paper platform at two known points outside normal field of platform operation

摘要

The position of a spring loaded and angled paper platform is measured by a photodiode transmitter (44) and receiver (43) with transmitter supply (110) and an analogue to digital convertor (115) for the receiver. At a time when the paper platform is outside it's normal working range such as during reloading electrical measurements are taken at two known points and these are used to calibrate the logarithmic characteristic using a processor (100).