Patent ID: 9211750
Filing Date: 2015-12-15
Classification: B41J

Abstract:
1. A liquid ejection apparatus comprising: a piezoelectric element that is displaced according to a driving signal; a pressure chamber whose inside is filled with a liquid and in which a pressure inside is increased or decreased by the displacement of the piezoelectric element based on the driving signal; a nozzle that communicates with the pressure chamber and is capable of ejecting the liquid filled in the inside of the pressure chamber through the increase or decrease of the pressure in the inside of the pressure chamber; a driving signal supply unit that supplies the driving signal to the piezoelectric element; a detection unit that detects a change of an electromotive force of the piezoelectric element as a residual vibration signal based on the change of the pressure in the inside of the pressure chamber, which is generated after the driving signal is supplied to the piezoelectric element; a comparison signal generation unit that generates a first comparison signal obtained by binarizing the residual vibration signal with a first threshold value and a second comparison signal obtained by binarizing the residual vibration signal with a second threshold value; and a determination unit that determines an ejection state of the liquid in the nozzle based on at least the first comparison signal and the second comparison signal, wherein the first threshold value substantially coincides with an amplitude center level of the residual vibration signal, and wherein the determination unit includes a phase index data generation unit generating phase index data according to a phase of the residual vibration signal based on the first comparison signal and an amplitude index data generation unit generating amplitude index data according to the amplitude of the residual vibration signal based on at least the second comparison signal and determines an ejection state of a liquid in the nozzle based on the phase index data and the amplitude index data.