Liquid level sensor for ink jet printers
US5583544A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1994 |
| Grant date | Dec 10, 1996 |
| Priority date | — |
| Expiry date | Oct 6, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2002/17579
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The ink level sensor of the invention comprises an ink container having a generally cylindrical shield extending downward from its top to define shielded and unshielded compartments within the container. Ink, but not foam, froth or mist, flows under the shield to the shielded compartment. A plurality of conductive rods of differing length extend downwardly into the shielded compartment from the container top. The rods are connected to an impedance network which provides signals representative of the ink level inside the container. A vacuum source can be connected to each compartment to maintain pressure equilibrium in the compartments and to prevent foam, froth or mist from entering the shielded compartment. Alternatively, a return pump is used to force ink into the container such that each compartment can be vented to the atmosphere.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.