Patent ID: 6409295
Filing Date: 2002-06-25
Classification: B41J

Abstract:
An ink-jet device comprising:a print head having an ink chamber which stores ink to be ejected therefrom and an electrostrictive member which deforms the ink chamber to increase a pressure of said ink chamber to eject the ink; and a drive unit which drives said print head such that said ink is ejected as one or more ink drops in a multi-tone print mode and as a single ink drop in a monotone print mode; wherein said drive unit includes a pulse generator which: (i) supplies a variable number of drive pulses to said print head in a first cycle so as to cause the ink chamber to successively eject a number of ink drops equal to the variable number of drive pulses in the multi-tone print mode, and (ii) supplies a fixed number of drive pulses to said print head in a second cycle shorter than the first cycle so as to cause the pressure of said ink chamber to be gradually increased to finally eject the single ink drop in the monotone print mode; and wherein an amplitude of the drive pulses is constant between the multi-tone print mode and the monotone print mode.