Ink concentration measuring and control and control circuit
US5373366A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 4, 1993 |
| Grant date | Dec 13, 1994 |
| Priority date | — |
| Expiry date | May 4, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/1211
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an ink concentration measuring circuit, a light emitting diode emits light toward an ink cell. A first photo diode receives reflected light from the ink cell and provides a reference signal and a second photo diode receives direct light through the ink cell and provides an ink signal. A ratio of the reference signal to the ink signal is then calculated and used to determine a concentration of ink in the ink cell. Since changes in the ink temperature affect the ink concentration, the ink temperature may be measured and the result used to modify the ratio, compensating for the changes in ink temperature. Also, ink pressure may be measured and used to modify the ratio, compensating for changes in the dimensions of the ink cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.