Patent ID: 7611231

Claim:
An inkjet printhead including a cavity unit comprising: a plurality of nozzles arranged in at least one row in a first surface of the cavity unit; at least one common ink chamber extending along the row of the nozzles so as to distribute therefrom ink to the nozzles; an ink introducing passage having an entrance on a second surface of the cavity unit which is opposite to the first surface, and extending toward the first surface to be connected to a first one of two opposite longitudinal end portions of the common ink chamber so as to introduce ink into the common ink chamber; and an uppermost stream point, in terms of ink flow, in a bottom surface of the common ink chamber being located, as seen in a direction perpendicular to a direction in which the ink introducing passage extends as well as a longitudinal direction of the common ink chamber, on a side of a second longitudinal end portion of the common ink chamber, with respect to an end point of the entrance of the ink introducing passage, which end point is on the side remote from the second longitudinal end portion; wherein the cavity unit comprises a plurality of plates as stacked, wherein the common ink chamber is constituted by a through-hole formed through a first one of the plates, wherein the ink introducing passage is constituted by the entrance that is formed through a second one of the plates which is an outermost plate on the side of the second surface, and a connection opening formed through at least one third plate interposed between the first plate and the second plate, and wherein an inner surface of the ink introducing passage is stepped with at least two shoulders on the side remote from the second longitudinal end portion, by superposing the entrance and the connection opening over the first longitudinal end portion of the common ink chamber.