Apparatus for measuring the state of formation of a sheet of paper
US4707223A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1985 |
| Grant date | Nov 17, 1987 |
| Priority date | — |
| Expiry date | Jul 12, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/86
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This invention relates to an apparatus for continuously measuring the state of formation of a sheet of paper which comprises: --means for moving a sheet of paper at a predetermined speed; --a light source directing a laser beam through said sheet; --a means for picking up the laser light transmitted, then for converting it into an electrical signal; --electronic processing means for separating this electrical signal into two components; --means for calculating from these components the index I representative of the state of formation; --a means for displaying the value of this index I; wherein the laser beam is polarized, and the apparatus further comprises, between the sheet and the means for picking up the laser light transmitted, a polarizer of which the axis of polarization is perpendicular to the axis of polarization of the laser beam transmitted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.