Patent ID: 8057002

Claim:
A method of driving an ink-jet head, comprising: providing an ink-jet head comprising: a substrate having an ink flow path for supplying ink, a plurality of partition walls spaced apart at a preselected interval to form a plurality of grooves arranged parallel to one another and disposed in communication with the ink flow path for receiving ink, the partition walls having deformable side walls; a plurality of electrodes each connected to the respective side walls to form an actuator that is driven by a drive pulse to deform the side walls to vary the volume in the grooves to thereby eject ink from the grooves; a nozzle plate connected to the substrate and having a plurality of nozzle openings each disposed in communication with respective ones of the grooves so that when the actuators are driven ink is ejected from the grooves through the nozzle openings and onto a recording medium; application means for applying to the actuators a drive pulse with a predetermined voltage to drive the actuators by deformation of the side walls to thereby eject ink from the grooves through the nozzle openings while providing a rest time during which the actuators are not driven; and control means for generating a plurality of drive pulses that are applied by the application means for one-dot print cycle to change a discharge volume of the ink ejected from the grooves through the nozzle openings and onto the recording medium; and setting, by the control means, a duration of each of an initial drive pulse and a final drive pulse, from among the plurality of generated drive pulses, so that the duration of the initial drive pulse is set to a value in the range of from 1/1.5 to 1/2.9 of the duration of the final drive pulse; wherein in one-dot print cycle, each of a total time consisting of the duration of one of the initial drive pulses and a corresponding rest time is set to be constant with one another and twice the duration of the final drive pulse.