Ink level sensing probe system for an ink jet printer
US5386224A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1993 |
| Grant date | Jan 31, 1995 |
| Priority date | — |
| Expiry date | Apr 26, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/17593
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A discrete ink level sensing system according to the present invention includes a level sensing probe (130) with at least first and second level sensing pads (178, 180) that is placed in an ink reservoir (28). The level sensing system uses electrical conductivity of the ink to detect when the upper surface level of the ink is lower than the lowest points of the level sensing pads. The upper and lower level sensing pads are electrically connected by a sense resistor (182). A voltage sensor (174) detects across the sense resistor a voltage that depends on the ink conductivity and the position of an upper surface level of the ink with respect to the lowest points of the first and second level pads. The value of the voltage is sent to a CPU (154) that signals a user that a predetermined amount of ink should be added to the reservoir.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.