Patent ID: 7600317

Claim:
A manufacturing method of an ink-jet head, comprising the steps of: layering with an adhesive a first plate having a nozzle hole that ejects an ink droplet and a second plate having a communication hole so that, on an interface between the first plate and the second plate, an opening of the nozzle hole is included within an opening of the communication hole; and applying pressure to the first and second plates in their layered direction so that the pressure is applied to only a region outside of the opening of the communication hole with respect to a plane parallel to planes of the first and second plates, wherein the step of applying pressure occurs after the step of layering and in the absence of any pressure causing the adhesive to enter into the nozzle hole having been previously applied; wherein, in the step of applying pressure, pressure is applied to the first and second plates so that the pressure is applied to a part of a region sandwiched between the outer edge of the opening of the communication hole and a first circle that is concentric with the opening of the nozzle hole and has a radius of twice larger than an average distance from a center of the opening of the nozzle hole to a line of intersection of the interface and a sidewall of the communication hole; wherein: the opening of the communication hole has a circular shape; and in the step of applying pressure, pressure is applied to the first and second plates so that the pressure is applied to a part of a region sandwiched between the first circle and a second circle that defines the opening of the communication hole; and wherein: the first plate has an ink ejection face, from which an ink droplet is ejected, opposite to the interface; the step of layering further comprises the step of preparing for pressure application in which a third plate having any one of a recess and a relief hole is layered on the ink ejection face of the first plate so that the first plate is intervened between the second and third plates and so that a centerline of any one of the recess and the relief hole aligns with the centerline of the nozzle hole, an opening of any one of the recess and the relief hole having a radius equal to or larger than the radius of the second circle and equal to or smaller than the radius of the first circle; and in the step of applying pressure, pressure is applied via the third plate to the first and second plates.