Patent ID: 8186811

Claim:
An inkjet printing apparatus comprising: a flow channel plate including an ink inlet configured to receive ink, a pressure chamber configured to contain the ink, and a nozzle connected to the pressure chamber and configured to eject the ink; a piezoelectric actuator configured to exert a piezoelectric driving force to the ink by modifying a volume of the pressure chamber; an electrohydrodynamic actuator configured to exert an electrohydrodynamic driving force to the ink; a piezoelectric voltage applier configured to apply a piezoelectric driving voltage to the piezoelectric actuator such that the volume of the pressure chamber is reduced so as to eject an ink droplet; and an electrohydrodynamic voltage applier configured to apply a first electrohydrodynamic driving voltage and a second electrohydrodynamic driving voltage to the electrohydrodynamic actuator, the first electrohydrodynamic driving voltage being applied so as to generate a jet from the ink droplet such that the jet is ejected towards a printing medium, the second electrohydrodynamic driving voltage having a polarity opposite to that of the first electrohydrodynamic driving voltage, the second electrohydrodynamic driving voltage being applied so as to restore the ink droplet to the nozzle.