Chip structure of inkjet printhead and method of estimating working life through detection of defects
US6378978B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 2000 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Nov 29, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/14072
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An inkjet printhead chip structure and a method of estimating the working life through the detection of any defect on the chip structure. The method includes laying a metallic layer such as a tantalum layer over the chip and then shaping the metallic layer into a protective layer circuit. A portion of the metal protective layer covers the heating elements embedded in the chip. In printing, the heating elements heat up the ink to produce jets of ink. However, a portion of the heat is transferred to the metal protective layer thereby raising its temperature. Heat on the metal protective layer combined with any strayed residual ink bubbles that impinge upon the surface of the metal protective layer causes the metal to age. Since resistance of the metal protective layer will increase proportionally to the amount of aging, a measurement of the resistance is capable of estimating how much longer a given chip is suitable for use. Furthermore, if this special circuit layout runs across each long side of an ink slot, any cracks along the direction of the ink slot are detectable during resistance measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.