Control circuit for regulating temperature in an ink-jet print head
US5475405A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1993 |
| Grant date | Dec 12, 1995 |
| Priority date | — |
| Expiry date | Dec 14, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/04591
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A temperature control circuit regulates temperature in an ink-jet print head. The control circuit includes a thermal sensor mounted on the print head to measure its temperature and a temperature level detector to determine whether the measured print head temperature exceeds a threshold temperature. The temperature level detector outputs a first signal when the measured print head temperature exceeds the threshold temperature and a second signal when the measured print head temperature does not exceed the threshold temperature. The control circuit also has first logic circuitry to output warming pulses upon receipt of the second signal. The warming pulses have energy insufficient to deposit an ink drop from the print head. Second logic circuitry is configured to output warming pulses to non-selected nozzles of the print head and firing pulses to selected nozzles. In this manner, the print head is automatically warmed via the warming pulses so long as the print head temperature is below a prescribed level. An ink-jet print head incorporating the control circuit is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.