METHOD FOR ELIMINATION OF MISDIRECTED SATELLITE DROPS IN THERMAL INK JET PRINTHEADS
Original Publication Date: 1995-Feb-28
Included in the Prior Art Database: 2004-Apr-07
Xerox Disclosure Journal
Misdirected satellite drops in thermal ink jet devices may cause observable print quality defects of a thermal ink jet printer. This is especially true when the thermal ink jet printing device is used in bi-directional carriage printing applications, where satellite drops can fall within the main spot when printing in one 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 misshaped may result in 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 a nozzle to a copy sheet. The elongation always occurs along the process direction, and 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 thermal ink jet devices, this tail bending has typically been directed toward the top or apex of the channel structures.