Patent ID: 7475960

Claim:
A liquid ejection apparatus, comprising: an ejection head which includes: a nozzle through which a droplet of liquid is ejected onto an ejection receiving medium; a pressure chamber which accommodates the liquid to be ejected from the nozzle; and a piezoelectric element which is provided at the pressure chamber and applies an ejection force to the liquid inside the pressure chamber; a pressure sensor which is provided at the pressure chamber and the pressure sensor generates a determination signal corresponding to pressure in the pressure chamber; an integration device which integrates the determination signal corresponding to pressure in the pressure chamber obtained by the pressure sensor for a prescribed integration time period to obtain an integration result; and an ejection abnormality judgment device which judges whether or not an ejection abnormality occurs in the nozzle, according to a comparison result of comparing the integration result obtained from the integration device with a previously established threshold value.