Patent ID: 7490920
Filing Date: 2009-02-17
Classification: B41J

Abstract:
1. A method of driving a droplet jetting head which has cavities for containing a predetermined liquid, piezoelectric elements, each for generating pressure in each cavity in accordance with an applied driving signal, and nozzle openings, from each of which the liquid compressed by each piezoelectric element is jetted as a droplet, the method comprising: a driving step of driving the droplet jetting head by applying to one or more of the piezoelectric elements corresponding to the nozzle openings which cannot jet a droplet by a normal signal form of the driving signal, a forced jetting driving signal having an enlarged signal form for forcedly jetting the liquid of half of an excluded volume from the nozzle opening, wherein the excluded volume is a maximum quantity removable from the cavity by compression using the piezoelectric element; and a control step of applying to the other piezoelectric elements to which the forced jetting driving signal is not applied, a micro driving signal for generating micro pressure by which no droplet is jetted from the nozzle opening corresponding to each of the other piezoelectric elements, wherein the driving step of driving the droplet jetting head by applying the forced jetting driving signal and the control step of applying the micro driving signal are performed in parallel, and wherein the forced jetting driving signal is applied to those individual nozzles which cannot jet a droplet by a normal signal form of the driving signal and the micro driving signal is applied to those individual nozzles to which the forced jetting driving signal is not applied.