Patent ID: 7198360

Claim:
An inkjet printing head comprising: a flow path unit including: a manifold as a common ink chamber; a plurality of individual ink flow paths, each individual ink flow path extending from the manifold and including a pressure chamber connected to a nozzle; an opening communicating with the manifold and being opened to outside the flow path unit; a plurality of thin plate members laminated through an adhesive agent, the plurality of thin plate members including at least one thin plate member having a plurality of first holes and a second hole formed therein, each first hole being a part of an individual ink flow path, and the second hole being a part of the opening or a part of the manifold; a hole group encircling groove that encircles a hole group including at least part of the plurality of first holes, wherein the hole group encircling groove includes: curved portions formed along a shape of all the first holes located in an outermost circumference of a corresponding hole group, and the second hole being located outside a region encircled by the hole group encircling groove; and an inner groove that encircles at least one first hole of the hole group formed on the thin plate member, the inner groove being formed in the region encircled by the hole group encircling groove and including a curved portion formed along a shape of the first hole that is encircled by the inner groove.