Patent ID: 7578567

Claim:
A liquid container comprising: a container body having a liquid delivery opening for delivering the liquid reserved inside to the outside; and a liquid sensor mounted on the container body, wherein the liquid sensor including: a vibration cavity forming base portion having a first surface and a second surface facing each other, a cavity for receiving a medium to be sensed being formed to be opened toward the first surface so that the bottom surface of the cavity can be vibrated; a piezoelectric element having a first electrode that is formed on the 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 flow path forming base portion laminated the first surface of the vibration cavity forming base portion, the flow path forming base portion being formed with a liquid supply path for supplying liquid to be sensed to the cavity and having a first cross sectional area, and a liquid discharge path for discharging liquid to be sensed from the cavity and having a second cross sectional area, wherein the liquid container further comprises: a supply side buffer chamber communicating with the liquid supply path and having a third cross sectional area larger than the first cross sectional area; an inflow opening communicating with the supply side buffer chamber and having a fourth cross sectional area smaller than the third cross sectional area; and a discharge side buffer chamber communicating with the liquid discharge path, and having a fifth cross sectional area larger than the second cross sectional area; and a discharge opening communicating with the discharge side buffer chamber and having a sixth cross sectional area smaller than the fifth cross sectional area, and wherein the liquid inside the container body is supplied to the cavity through the inflow opening, the supply side buffer chamber and the liquid supply path and is discharged from the cavity through the liquid discharge path, the discharge side buffer chamber and the discharge opening.