Patent ID: 7708388

Claim:
A liquid ejection head, comprising: a liquid chamber, which stores liquid therein; a nozzle orifice, adapted to eject a liquid droplet therefrom; a pressure generating portion, provided in a liquid channel communicating with the liquid chamber and the nozzle orifice; and a liquid supply port, arranged between the liquid chamber and the pressure generating portion, wherein an inertance of the nozzle orifice Mn and an inertance of the liquid supply port Ms are greater than an inertance of the pressure generating portion Mc; and wherein the inertance of the nozzle orifice Mn, the inertance of the liquid supply port Ms and the inertance of the pressure generating portion Mc are expressed as the following equations: Mn=ρLn/Sn Ms=ρLs/Ss ; and Mc=ρLc/Sc; where ρ denotes a density of liquid, Ln denotes a length of the nozzle orifice, Sn denotes a cross-section of the nozzle, Ls denotes a length of the liquid supply port, Ss denotes a cross-section of the liquid supply port, Lc denotes a length of the pressure generating portion and Sc denotes the cross-section of the pressure generating portion.