Patent ID: 7334878
Filing Date: 2008-02-26
Classification: B41J

Abstract:
1. A liquid ejection head comprising a plurality of liquid ejection elements arrayed in a flat area on a substrate, each liquid ejection element including: a liquid chamber for holding a liquid to be ejected; a heating element disposed in the liquid chamber, for generating a bubble in the liquid in the liquid chamber by heating the liquid; and a nozzle for ejecting the liquid in the liquid chamber when the bubble is generated by the heating element, wherein, of the plurality of heating elements, heating elements at M-th positions as measured from an end of the array of heating elements are disposed such that the center of each of these heating elements is located exactly on or close to a first line extending in the same direction as the direction in which the heating elements are arrayed, while heating elements at N-th positions as measured from the end of the array of heating elements are disposed such that the center of each of these heating elements is located exactly on or close to a second line extending in the same direction as the direction in which the heating elements are arrayed, the first and second lines being parallel with each other and being spaced from each other by δ (real number greater than 0), Ms being odd or even numbers, Ns being even numbers if Ms are odd numbers or odd numbers if Ns are even numbers; each liquid chamber is formed to have a U-like shape in horizontal cross section such that a wall thereof surrounds three sides of a heating element disposed in the liquid chamber; the heating elements are arrayed such that the heating elements disposed on or close to the first and second lines are located, as a whole of heating elements, at regular intervals of P; the liquid chambers are disposed such that an open side of each liquid chamber whose wall surrounds three sides of one of heating elements located exactly on or close to the first line faces in a direction opposite to a direction in which an open side of each liquid chamber whose wall surrounds three sides of one of heating elements located exactly on or close to the second line faces; a gap Wx (real number greater than 0) is formed at least between each adjacent liquid chambers disposed at intervals of 2P on or close to the first line or between each adjacent liquid chambers disposed at intervals of 2P on or close to the second line such that adjacent liquid chambers are spaced from each other by the gap Wx in the direction in which the liquid chambers are arrayed; a gap Wy (real number greater than 0) is formed between the liquid chambers disposed on or close to the first line and the liquid chambers disposed on or close to the second line such that the liquid chambers disposed on or close to the first line are spaced by the gap Wy from the liquid chambers disposed on or close to the second line in a direction perpendicular to the direction in which the liquid chambers are arrayed; and flow channels each having a width equal to Wx are formed by the gaps Wx, and a flow channel having a width equal to Wy is formed by the gap Wy.