Patent ID: 6698954
Filing Date: 2004-03-02
Classification: B41J,G06K

Abstract:
A printing apparatus for printing ink dots on a print medium during main scan passes, comprising:a print head having a plurality of nozzles and a plurality of ink-expulsion drive elements for jetting ink droplets from each of the plurality of nozzles; a main scan driver for performing main scan by moving at least one of the printing medium and the print head; a sub-scan driver for performing sub-scan feed by moving one of the printing medium and the print head; a head driver for presenting a drive signal to each of the ink-expulsion drive elements in response to a print signal; and a controller for controlling printing operations, wherein the head driver includes: a maskable drive signal generator capable of selectively generating for each main scan pass any of n types of maskable drive signals where n is an integer equal to 2 or greater; and a drive signal masking section that generates the drive signal to be supplied to the ink-expulsion drive elements, by masking the maskable drive signal according to the print signal on a per-pixel basis; and wherein the controller executes printing, on at least a part of the print medium, according to a specific printing scheme wherein printing ink dots on each raster line is completed in plural main scan passes while employing each of the n types of maskable drive signals on each raster line while continuously using one of the n types of maskable drive signals throughout one main scan pass.