Patent ID: 7204579

Claim:
A droplet discharging head, comprising: a nozzle plate formed with a first nozzle and a second nozzle which eject liquid; a first pressure chamber which is connected to the first nozzle and is filled with the liquid to be discharged from the first nozzle; a first piezoelectric element which generates pressure for causing pressure change in the liquid inside the first pressure chamber, and thereby causes a droplet to be discharged from the first nozzle; a second pressure chamber which is connected to the second nozzle and is filled with the liquid to be discharged from the second nozzle; and a second piezoelectric element which generates pressure for causing pressure change in the liquid inside the second pressure chamber, and thereby causes a droplet to be discharged from the second nozzle, wherein: if an ejection direction of the liquid which is ejected from the first nozzle and the second nozzle is regarded as a downward direction, the first piezoelectric element is disposed on an upper surface of the first pressure chamber and the second piezoelectric element is disposed on an upper surface of the second pressure chamber, the first pressure chamber is arranged below the second pressure chamber and the first pressure chamber and the second pressure chamber have different distances to the nozzle plate, a flow passage distance of a first nozzle supply passage between the first pressure chamber and the first nozzle differs from a flow passage distance of a second nozzle supply passage between the second pressure chamber and the second nozzle, the second pressure chamber is farther away from the nozzle plate than the first pressure chamber, a common flow passage which supplies the liquid to the first pressure chamber and the second pressure chamber is provided in a layer located above the second piezoelectric element, a first supply side supply passage which leads the liquid from the common flow passage to the first pressure chamber and a second supply side supply passage which leads the liquid from the common flow passage to the second pressure chamber are straight extended directly below from a bottom surface of the common flow passage, a flow passage distance of the first supply side supply passage between the common flow passage and the first pressure chamber differs from a flow passage distance of the second supply side supply passage between the common flow passage and the second pressure chamber, the first nozzle supply passage and the second nozzle supply passage are formed to have flow passage shapes whereby acoustic resistances and acoustic inertances of the first nozzle supply passage and the second nozzle supply passage are approximately same, and the first supply side supply passage and the second supply side supply passage are formed to have flow passage shapes whereby acoustic resistances and acoustic inertances of the first supply side supply passage and the second supply side supply passage are approximately same.