Patent ID: 7703877

Claim:
A liquid ejection apparatus, comprising: a nozzle which ejects liquid; a pressure chamber which is connected to the nozzle; an actuator which generates pressure applied to the liquid inside the pressure chamber, the actuator driving liquid ejection for ejecting the liquid from the nozzle, the actuator driving vibrating action to the liquid for causing a free surface of the liquid in the nozzle to vibrate to an extent that does not eject the liquid from the nozzle; a viscosity state judgment device which judges viscosity states of the liquid in a vicinity of the free surface of the liquid in the nozzle, the viscosity states including a first state in which the liquid ejection from the nozzle is possible and the vibrating action is not required for the nozzle, a second state in which the liquid ejection from the nozzle is possible and the vibrating action is required for the nozzle, and a third state in which the liquid ejection from the nozzle is not possible and restoration to the first state is possible if the vibrating action is performed for the nozzle; and a control device which, in a case where the liquid ejection from the nozzle is to be performed, controls in the first state so as to perform the liquid ejection from the nozzle without performing the vibrating action for the nozzle, and controls in either one of the second state and the third state so as to perform the liquid ejection from the nozzle after performing the vibrating action for the nozzle, and which, in a case where the liquid ejection from the nozzle is not to be performed, controls in either one of the first state and the second state so as not to perform the vibrating action for the nozzle, and controls in the third state so as to perform the vibrating action for the nozzle, wherein the viscosity state judgment device judges at least one of an evaporation volume and a solvent concentration of the liquid at the free surface in the nozzle in order to judge the viscosity states of the liquid in a vicinity of the free surface of the liquid in the nozzle.