ON-LINE PAPER SHEET FORMATION CHARACTERIZING METHOD AND DEVICE

摘要

A device for characterizing the formation of a sheet material is described. The device comprises a basis weight sensor for measuring the basis weight of the sheet material as the material passes through the sensor and signal processing circuitry which receives a signal from the basis weight sensor indicative of the measured basis weight and which produces three types of outputs, which outputs characterize: (1) the magnitude of variation in the sheet basis weights (2) the strength of the weakest portion or portions of the sheets and (3) the size of the flocs comprising the sheet. The basis weight sensor includes a light pipe which is held against the sheet, as the sheet moves through the sensor, and which directs a small spot of light transmitted through the sheet to a light detecting device. The magnitude of variation in the sheet basis weight is computed to be proportional to the true root-mean-square variation in the basis weight of the sheet.