Method and apparatus for reducing the size of drops ejected from a thermal ink jet printhead
US5673069A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1994 |
| Grant date | Sep 30, 1997 |
| Priority date | — |
| Expiry date | Aug 1, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/0458
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The volume of drops ejected from thermal ink jet printheads varies with the temperature of the printhead. The variation in drop volume degrades print quality by causing variations in the darkness in black and white text, the contrast of gray scale images, and variations in the chroma, hue, and lightness of color images. The present invention reduces the range of drop volume variation by reducing the range of printhead temperature variation during the print cycle by keeping the printhead temperature above a reference temperature. When the printhead temperature falls below the reference temperature during a print cycle the printhead is heated with nonprinting pulses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.