Patent ID: 7618116

Claim:
A printing apparatus for printing by using a printhead which has a first nozzle array and a second nozzle array, each having a plurality of first nozzles from which a first amount of the ink is discharged and a plurality of second nozzles from which a second amount of the ink is discharged and including main nozzles to be used for printing on a printing medium and dummy nozzles not to be used for printing on the printing medium, comprising: driving means for driving the nozzles of the first nozzle array and the second nozzle array; referring means for referring, within a predetermined period, a first flag signal indicating selection of the main nozzles or the dummy nozzles in the first nozzle array and the second nozzle array, and a second flag signal indicating selection of the first nozzles or the second nozzles in the first nozzle array and the second nozzle array; determination means for determining a number of shots of preliminary discharge in a preliminary discharge mode executed in response to a preliminary discharge request; and control means for executing, on the basis of the number of shots of preliminary discharge determined by said determination means, first preliminary discharge control to drive said driving means while alternately selecting the main nozzles and the dummy nozzles on the basis of a value of the first flag signal referred by said referring means, and second preliminary discharge control to drive said driving means while alternately selecting the first nozzles and the second nozzles on the basis of a value of the second flag signal referred by referring means, wherein said control means, by switching a value of the first flag signal in the first preliminary discharge and switching a value of the second flag signal in the second preliminary discharge every lapse of the predetermined period, further executes in the first preliminary discharge, sequential drive of the first nozzles and the second nozzles in the first nozzle array and the second nozzle array; and in the second preliminary discharge, sequential drive of the main nozzles and the dummy nozzles in the first nozzle array and the second nozzle array.