Ink jet printer and printing method

Abstract

An ink jet printer has a number of ink discharge nozzles, a number of actuators respectively associated with the nozzles and arranged to create pressure waves in the ink to be discharged from the respective nozzles, and a controller arranged to apply drive signals to the actuators in accordance with print instructions for an image to be printed. The drive signals include print pulses causing ink droplets to be ejected from the nozzles at timings when the respective nozzle faces an image part of a print medium, and spitting pulses causing ink droplets to be ejected from the nozzles at timings when the respective nozzle faces a non-image part of the print medium. The drive signals further include pre-fire pulses which have an amplitude below a threshold at which ink droplets are ejected, and the controller is arranged to apply the spitting pulses in the form of combined pulse sequences that each include a number of pre-fire pulses preceding the spitting pulse.

Dependencies are inferred from the claim text.