Clocked optical sensing apparatus
US4835403A · kind A · utility
6Cited by
5References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 30, 1986 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | Dec 30, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65H2701/1912
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A document sensor comprises a source of infrared light directed toward a document and a photocell for reacting to the light as it is reflected from the document. A clock drives the light source to send cyclically recurring light pulses toward the document. The clock source also enables a detector each time that the document light source is switched on. After a predetermined number of successive reflected light pulses have been picked up, a document present signal is given.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.