Thermal ink jet printing system with continuous ink circulation through a printhead
US5818485A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1996 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Nov 22, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2202/12
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An ink jet printing system is provided with a re-circulating ink system which continuously moves ink through the printhead preventing ink thickening or drying out of the ink at the nozzles during non-print periods. Several printhead embodiments are disclosed in which a continuous ink path is established through the printhead by forming ink channels in various internal portions of the printhead. In one embodiment the ink flows through channels formed in an upper substrate through the non-ejecting nozzle area and exits through channels in which the ink heating resistors are located. In other embodiments the ink enters channels formed in an upper substrate and exits through channels formed in a lower substrate. Ink may be ejected through nozzles formed in a nozzle plate or directly from grooves which form a meniscus at the required ink ejection areas. The ink flow requires that a negative pressure gradient be established in the direction of the ink flow so that ink does not weep out at the nozzles or the open grooves as it moves therepast. The required pressures are provided by a pressure head comprising the ink supply reservoir being moved relative to the printhead in conjunction wit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.