Patent ID: 7661781

Claim:
A liquid ejection head, comprising: a liquid flow channel of which at least one wall is constituted by an elastic member; a nozzle which is provided at an end of the liquid flow channel; and a pressure generating device which generates a pressure pulse wave in liquid inside the liquid flow channel, wherein the liquid flow channel and the pressure generating device are composed in such a manner that the pressure pulse wave propagates as a soliton through the liquid in the liquid flow channel, and wherein: the liquid flow channel is formed in a substantially cylindrical shape; and the pressure generating device includes a controller which controls a full-width at half-maximum of the pressure wave propogating through the liquid in the liquid flow channel and a maximum amplitude of the pressure wave in such a manner that the following relationships are satisfied: w = a ⁢ h ⁢ ⁢ ρ R r 0 ⁢ ρ 0 , ⁢ v = Eh 2 ⁢ ρ 0 ⁢ a ⁢ ( 1 + r 0 a ) , ⁢ V ≅ π ⁡ ( a + r 0 ) 2 ⁢ w , ⁢ and V ≅ π 6 ⁢ w 3 , where w is the full-width at half-maximum of the pressure pulse wave propagating through the liquid in the liquid flow channel, v is a speed of the pressure pulse wave, a is a radius of the liquid flow channel, h is a thickness of the wall of the liquid flow channel, r 0 is the maximum amplitude of the pressure pulse wave, ρ R is a density of the wall of the liquid flow channel, ρ 0 is a density of the liquid in the liquid flow channel, and E is a Young's modulus of the wall of the liquid flow channel.