Ink level sensor for an inkjet print cartridge
US5682183A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1994 |
| Grant date | Oct 28, 1997 |
| Priority date | — |
| Expiry date | Oct 31, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/17566
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Disclosed is a method of determining imminent ink exhaustion in a thermal inkjet print cartridge based on the discovery that ink drop volume falls at a faster rate at high frequency firing rates than at low frequency firing rates as ink supply diminishes. The method includes warming the print cartridge printhead and ink to a predetermined temperature; then operating the print cartridge printhead at a first firing frequency to eject a volume of ink, said operating step including heating the ink and printhead, carrying away heat in the ejected volume of ink, and conveying a volume of cooler ink to the printhead to replace the ejected volume; and monitoring a first temperature change from the predetermined temperature. Then warming the same print cartridge printhead and ink to a predetermined temperature; operating the print cartridge printhead at a second firing frequency which is different than the first firing frequency to eject a volume of ink, said operating step including heating the ink and printhead, carrying away heat in the ejected volume of ink, and conveying a volume of cooler ink to the printhead to replace the ejected volume; and monitoring a second temperature change fr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.