PRINTER CONTROLLER CONFIGURED TO COMPENSATE FOR DEAD PRINTHEAD NOZZLES
A printer controller for compensating for an inoperative nozzle in a printhead is provided. The printhead includes a plurality of nozzles associated with each pixel to be printed, the printer controller being operative to control one or more operative nozzles associated with the same pixel as the inoperative nozzle to increase the amount of printing substance expelled by the one or more operative nozzles.
1 . A printer controller for compensating for an inoperative nozzle in a printhead, the printhead including a plurality of nozzles associated with each pixel to be printed, the printer controller being operative to control one or more operative nozzles associated with the same pixel as the inoperative nozzle to increase the amount of printing substance expelled by the one or more operative nozzles.
2 . A printer controller as claimed in claim 1 , wherein the printer controller compensates for the inoperative nozzle by increasing the amount of printing substance expelled by one or more operative nozzles expelling printing substance with a color substantially similar to the color expelled by the inoperative nozzle.
3 . A printer controller as claimed in claim 1 , wherein there are six nozzles associated with each pixel and the amount of printing substance expelled by each nozzle is bi-level.
4 . A printer controller as claimed in claim 1 , wherein information indicating inoperative nozzles is stored in a table.
5 . A printer controller as claimed in claim 4 , wherein the table is updated by performing an inoperative nozzle test including the steps of:
running a printhead nozzle test sequence;
converting inoperative nozzle information into an inoperative nozzle table; and,
writing the inoperative nozzle table to a memory of the printer controller.
6 . A printer controller as claimed in claim 1 , wherein the inoperative nozzle is associated with a black print channel, and wherein dot data intended for the inoperative nozzle is mapped into a plurality of operative nozzles associated with the same pixel as the inoperative nozzle in other color channels to produce a process black output substantially at a location on print media where the inoperative nozzle would have deposited a dot of a black printing substance in accordance with the dot data.
7 . A printer controller as claimed in claim 1 , wherein the increased amounts of printing substance expelled by the one or more operative nozzles forms a pixel with a color substantially similar to the color expelled by the inoperative nozzle.