METHOD FOR ELIMINATION OF MISDIRECTED SATELLITE DROPS IN THERMAL INK JET PRINTHEADS
Original Publication Date: 1995-Jun-30
Included in the Prior Art Database: 2004-Apr-07
Xerox Disclosure Journal
[Reprinted because of changes to the text of this disclosure. Originally printed in the JanuarylFebruary 1995 Xerox Disclosure Journal] Misdirected satellite drops in thermal ink jet devices may cause observable print quality defects in a thermal ink jet printer. This is especially true when the thermal ink jet printing device is used in bi-directional carriage printing applications and the satellite drops are misdirected along the process direction. In such cases, satellite drops can fall within the main spot when printing in one direction and outside the main spot in the other direction. When misdirected drops fall outside the main spot, the resultant drop is no longer round, but rather elongated in shape. The effectively larger and mis-shaped spot may result in optical density shifts in fine toned print patterns as well as ragged edges on printed text and lines. Whether or not the satellite related print quality defects are observed depends on the direction of relative motion between the printhead and the print medium, the process speed, and the throw distance from the nozzles to the print medium. If the elongation occurs along the process direction, the physical origin of the misdirected satellite has been observed to be caused by a "tail bending" of the ink drop ligament prior to break-off from the nozzle face. For Xerox thermal ink jet devices, this tail bending has typically been directed toward the top or apex of the channel structures.