Patent ID: 7322667

Claim:
A liquid detecting method for detecting liquid in a liquid container used in a liquid ejector using a liquid sensor, wherein the liquid sensor comprises: a vibration cavity forming base portion having a first surface and a second surface opposite to each other, in which a cavity for receiving the liquid as a detection object is opened at a side of the first surface, and a bottom of the cavity is capable of vibrating; a piezoelectric device including a first electrode formed at a side of the second surface of the vibration cavity forming base portion, a piezoelectric layer laminated on the first electrode, and a second electrode laminated on the piezoelectric layer; and a liquid supply port and a liquid discharge port for supplying and discharging the liquid to and from the cavity, the method comprising: a head cleaning step of performing a head cleaning operation after maintaining for a predetermined time or longer a state where there is no flow of fluid into and from the cavity through the liquid supply port and the liquid discharge port; and a detecting step of detecting presence or absence of the liquid by applying a drive signal to the piezoelectric device of the liquid sensor after the head cleaning operation.