Paper property sensing system

摘要

A sensor system for measuring physical properties of a sheet. In one embodiment, the sensor system measures paper curl and thickness using two sensors, each of which includes a member, a base, and measurement circuit. The two members are positioned in opposition to each other and both contact the sheet as it passes between them. Each member is coupled to a base, which includes a measurement circuit. Each measurement circuit measures the displacement of its associated member. In another embodiment, the sensor system measures stiffness and curl using two pairs of opposed sensors. In yet another embodiment, the sensor system measures thermal diffusivity of a sheet of paper using three sensors, one of which includes a heater for heating the sheet of paper and the other two sensors include thermocouples in contact with the sheet of paper for sensing the heat of the paper.