Patent ID: 8038264

Claim:
A liquid droplet jetting head which jets droplets of a liquid, comprising: a channel unit having: a plurality of nozzles which are formed in the channel unit and which form a nozzle group arranged in a row in a first direction at a first interval; a plurality of pressure chambers which are formed in the channel unit, each of which communicates with one of the nozzles and which form a first pressure chamber group and a second pressure chamber group, the first pressure chamber group including a first pressure chamber which is positioned nearest to the second pressure chamber group, the second pressure chamber group including a second pressure chamber which is positioned nearest to the first pressure chamber group, and the plurality of pressure chambers being arranged in a row in the first direction such that a gap between the first pressure chamber and the second pressure chamber is larger than the first interval; a common liquid chamber which is formed in the channel unit, which communicates with the plurality of pressure chambers, and which is extended in the first direction corresponding to the plurality of pressure chambers arranged in the row; a liquid supply passage which supplies the liquid to the common liquid chamber from outside of the channel unit; and an auxiliary supply passage which supplies the liquid to the common liquid chamber through the gap, and a pressure applying mechanism which applies a jetting pressure to the liquid in the plurality of pressure chambers; wherein the pressure applying mechanism is a piezoelectric actuator which changes a volume of each of the pressure chambers independently, and which is joined to a surface of the channel unit; and wherein the piezoelectric actuator is arranged to overlap with the first and second pressure chamber groups so that the piezoelectric actuator straddles the first and second pressure chamber groups; and wherein the auxiliary supply passage is a sub supply passage which penetrates through the piezoelectric actuator to reach the common liquid chamber.