Patent ID: 9487000
Filing Date: 2016-11-08
CPC Classification: B41J

Claim Text:
1. A liquid droplet ejecting device comprising: multiple pressure chambers communicating with multiple nozzles, to contain liquid; a vibration plate, disposed extending along the pressure chambers; multiple piezoelectric elements disposed facing the multiple chambers respectively via the vibration plate; a drive waveform generator to generate drive voltage for the piezoelectric elements; a residual vibration detector to detect an amplitude of a residual vibration waveform occurring within the pressure chamber after the piezoelectric elements are driven; and a controller to calculate a damping ratio of the residual vibration waveform detected by the residual vibration detector based on a plurality of the detected amplitudes of the residual vibrations, and to determine whether abnormal ejection occurs based on the calculated dampening ratio; wherein predetermined values are set to a relation “a first predetermined value<a second predetermined value<a third predetermined value”, wherein the controller determines that an air bubble is mixed in the pressure chamber, upon detecting that the damping ratio is greater than or equal to the third predetermined value.