Electronic document detector circuitry with feedback control
US4027154A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1975 |
| Grant date | May 31, 1977 |
| Priority date | — |
| Expiry date | Dec 29, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K13/067
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The disclosure relates to an electronic document detector particularly adapted for but not limited to use in a document recording system. The document detector comprises a light source, a current source which includes a light sensitive element spaced from the light source and arranged for receiving at least a portion of the light output of the light source for providing a current having a magnitude directly related to the amount of light received by the element, wherein the space between the light source and the light sensitive element defines a path in which documents to be detected traverse. As each document traverses the path, the light sensitive element is shielded from the light source. A current sink coupled to the current source has an input and an output for providing at its output an intermediate control voltage having a magnitude related to the magnitude of the current provided by the current source and within a first range below a given level and within a second range above the given level. A voltage detector coupled to the output of the current sink provides a document indicative signal when the intermediate control voltage falls below the given level into the first ran…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.