Sensing media parameters
US6157791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1999 |
| Grant date | Dec 5, 2000 |
| Priority date | — |
| Expiry date | Jul 6, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/00763
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An embodiment of a media quantity sensing device and a media type sensing device includes a first, a second a third, and a fourth electrode. The first electrode is positioned above a media tray and the second electrode is positioned on the media tray below the media. The third and the fourth electrodes are positioned so that the media leaving the media tray passes between them. The media quantity sensing device further includes a measuring circuit coupled to a controller. The measuring circuit includes a first dual slope integrator to generate a first square wave output signal having a frequency dependent upon the dielectric constant of the media between the first electrode and the second electrode. The measuring circuit further includes a second dual slope integrator to generate a second square wave output signal having a frequency dependent upon the dielectric constant of the media between the third electrode and the fourth electrode. The measuring circuit also includes a frequency measurement unit to measure the frequencies of the first and the second square wave output signals. The controller reads the frequencies from the first and the second square wave output signals. The co…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.