Web defect monitor for abrupt changes in web density
US4011457A · kind A · utility
14Cited by
4References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 6, 1975 |
| Grant date | Mar 8, 1977 |
| Priority date | — |
| Expiry date | Aug 6, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8915
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electro-optical scanner for detecting variations in a web and generating output signals representative of the variations is provided with discriminator logic and alarm circuitry that indicates when the output signals shift from a value exceeding a predetermined positive (negative) threshold value to a value beyond a predetermined negative (positive) threshold value within a prescribed minimum period of time as an occurrence of an abrupt change in web density and processing circuitry for determining and indicating when the number of such occurrences per unit time exceeds a threshold or predetermined number.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.