Conductive brush paper position sensor
US4641949A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1985 |
| Grant date | Feb 10, 1987 |
| Priority date | — |
| Expiry date | Aug 26, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/00734
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
The present invention is concerned with a switching element comprised of oppositely disposed conductive fiber brushes and/or brush-like elements for detecting the presence or absence of paper at various locations in a xerographic copy machine. The oppositely disposed brushes are made from poly-acrylo-nitrile, a carbon based polymer material, which can be fabricated with relatively low values of resistance. Typical fiber bundles may consist of 6000 individual fibers each of 6-10 microns in diameter. In operation each individual conductive fiber acts as a separate electrical path through which the external circuit is completed. Passage of paper through the "nip" of the fiber to fiber electrical contact opens the circuit which is easily detected through associated circuitry which indicates the presence of paper. Likewise, arrays incorporating multiple such sensor switches may be fabricated for the purpose of indicating the size of the document interrupting specific low resistance fiber-fiber switches.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.