Method and apparatus for measuring and controlling the surface characteristics of sheet materials such as paper
US5654799A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1995 |
| Grant date | Aug 5, 1997 |
| Priority date | — |
| Expiry date | May 5, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/86
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An on-line laser triangulation position sensing system provides measurements of the surface features of a moving sheet such as paper. The measurements are correlatable with measurements made with standard laboratory surface smoothness testers and provide predictions of the printability of paper during its fabrication. The sensing system includes a segmented balance detector having a high frequency response. The sensing system further includes signal processing circuitry comprising a plurality of channels, each channel including a filter. The various filters have different cutoff frequencies for passing different frequency spectra representing ranges of surface feature scale sizes. The cutoff frequency of each filter is varied in response to variations in sheet speed. The sheet sensing system further includes a sheet stabilizer to minimize flutter in the measurement region and a standardizing member permitting performance verification of the sensor system at at least one scale size spectrum. The sensing system may also be provided with a sheet compressor to compress the sheet in the measurement region so as to simulate the pressures applied to sheet samples by laboratory air leak sm…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.