Patent ID: 8087760
Filing Date: 2012-01-03
Classification: B41J

Abstract:
1. A liquid ejection head comprising: a passage unit comprising a nozzle, which ejects liquid, a common liquid chamber, and an individual liquid passage, the individual liquid passage comprising a first passage, which has one end connected to the nozzle, a pressure chamber, which has one end connected to the other end of the first passage, a second passage, which has one end connected to the other end of the pressure chamber, and a restricted passage, which has one end connected to the other end of the second passage and the other end of which is connected to the common liquid chamber, the restricted passage being smaller than the second passage in the area of the passage(s) perpendicular to the direction of the flow of the liquid; and an actuator that can selectively take a first state in which the volume of the pressure chamber is V1 and a second state in which the volume of the pressure chamber is V2 larger than V1, the actuator changing from the first state into the second state and then returning to the first state to eject the liquid from the nozzle, Tc1 and Tc2 defined by the following Expressions 1 and 2 satisfying a condition that Tc1/Tc2 is substantially not less than 4.7 and not more than 5.5: where M′n, M′r, Mc2, and Cc2 are defined by the following Expressions 3 to 6, respectively: where Md, Ms, Ma, Mn, Mr, and Mc represent the inertances of the first passage, the second passage, the actuator, the nozzle, the restricted passage, and the pressure chamber, respectively; and Ca, Cc, Cd, and Cs represent the compliances of the actuator, the pressure chamber, the first passage, and the second passage, respectively.