Patent ID: 8684495

Claim:
A liquid ejection head comprising: a plate base material; and an actuator configured to apply a liquid-droplet ejection energy to liquid in the plate base material; wherein the plate base material has: a plurality of ejection holes formed therein in a thickness direction thereof for ejecting liquid droplets; and an ejection face having a plurality of ejection openings opened therein, wherein the liquid droplets are ejected through the plurality of ejection holes and the plurality of ejection openings; wherein the ejection face has a plurality of recessed portions arranged in a first direction formed therein, and at least one of the plurality of recessed portions has a bottom portion in which the plurality of ejection openings are opened; wherein the plurality of recessed portions include a plurality of pairs thereof, each pair being constituted by two recessed portions located side by side in the first direction and respectively having bottom portions in at least one of which the plurality of ejection openings are formed; wherein, the shorter that line segments are along the first direction, each connecting between outlines of respective two recessed portions of a corresponding one of the plurality of pairs of the recessed portions, the less that average values of lengths are in the first direction, each corresponding to an average value of lengths in the first direction of the respective two recessed portions of the corresponding one of the plurality of pairs of the recessed portions, each of the plurality of ejection openings of the corresponding one of the plurality of pairs having the same diameter.