Patent ID: 8167402

Claim:
An ink jet printing apparatus comprising: a printing head for ejecting ink by utilizing thermal energy generated by applying a pulse to a heater of said printing head; a pulse control means for controlling the pulse applied to the heater; a control means for causing said printing head to eject ink at a position at which said printing head faces a printing medium by applying a first pulse controlled by said pulse control means to the heater according to image data to perform printing; and a maintenance means for causing said printing head to eject ink at a position at which said printing head faces the printing medium by applying a second pulse controlled by said pulse control means to the heater, according to a predetermined pattern, to execute a maintenance, wherein the second pulse causes the heater to generate greater thermal energy than the first pulse, the greater thermal energy causing an area of a dot formed on the printing medium by the ink droplets ejected by the second pulse to be smaller than an area of a dot formed on the printing medium by the ink droplets ejected by the first pulse, and wherein ink is ejected to be separated into a plurality of ink droplets by the second pulse, the number of separated ink droplets being greater than the number of ink droplets ejected by the first pulse, and wherein an area of the ink droplets ejected by the second pulse are smaller than an area of a dot formed on the printing medium with the ink droplets ejected by the first pulse.