Patent ID: 6530635
Filing Date: 2003-03-11
Classification: B41J

Abstract:
A bidirectional printer configured to form ink dots of a plurality of color inks on a printing medium along forward and reverse passes of main scanning, the printer comprising:a printing head equipped with a plurality of nozzle groups each having a plurality of nozzles that eject ink droplets of identical color; a main scanning mechanism configured to perform the main scanning by moving at least one of the printing head and the printing medium; a head driver configured to cause ejection of ink droplets from at least some of the plurality of nozzles during the main scanning; a sub-scanning mechanism configured to perform sub-scanning by moving at least one of the printing head and the printing medium; and a controller configured to control printing process, the plurality of nozzle groups including: a first type nozzle group that is used to eject ink of a first ink group including at least one ink, the first type nozzle group ejecting ink droplets along both the forward and reverse passes of the main scanning, and a second type nozzle group that is used to eject ink of a second ink group including at least one ink, the second type nozzle group ejecting ink droplets along only a selected one of the forward and reverse passes of the main scanning, wherein the second type nozzle group includes 2Ã—i times the number of nozzles in the first type nozzle group where i is an integer of one or more.