Patent ID: 8596758

Claim:
A liquid ejection head comprising: a base plate member; and an actuator configured to apply liquid ejection energy to liquid in the base plate member; wherein the base plate member has (a) a plurality of ejection holes formed in a thickness direction of the base plate member and (b) an ejection face having a plurality of ejection openings opened therein, wherein liquid droplets are ejected through the plurality of ejection holes and the plurality of ejection openings; wherein the ejection face has a plurality of first recessed portions and a plurality of second recessed portions each of which extends in one direction and which are formed in the ejection face so as to be arranged in parallel with one another in a recessed-portions arranged direction that is perpendicular to the one direction, wherein the plurality of ejection openings are formed in bottom portions of the respective first recessed portions and each of the plurality of second recessed portions is a dummy groove having a bottom portion in which the plurality of ejection openings are not formed; and wherein each of the plurality of second recessed portions and a corresponding one of the plurality of first recessed portions are arranged side by side such that a separation distance therebetween in the recessed-portions arranged direction is equal to or greater than a separation distance in the recessed-portions arranged direction between two first recessed portions located side by side at the shortest distance among the plurality of first recessed portions and is shorter than a separation distance in the recessed-portions arranged direction between two first recessed portions located side by side at the greatest distance among the plurality of first recessed portions, wherein the corresponding one of the plurality of first recessed portions is nearest to said each of the plurality of second recessed portions among the plurality of first recessed portions.