Patent ID: 7908996

Claim:
A liquid coating apparatus for use with a liquid in which plural particles are dispersed, comprising: a head which comprises: plural nozzles; plural pressuring chambers; plural piezo elements with electrodes; and a common liquid chamber; wherein the plural nozzles eject the liquid, and a diameter of each nozzle is 5-8 times of the diameter of the plural particles; each pressuring chamber communicates to each nozzle; each piezo element is provided on each pressuring chamber to change a volume of the pressuring chamber, and the common liquid chamber communicates to each of the plural pressuring chambers; a sub-tank which stores the liquid and has an acceleration device to accelerate the plural particles to disperse in the liquid; a first flow channel which connects the common liquid chamber with the sub-tank; a second flow channel which connects the common liquid chamber with the sub-tank; a circulation device which circulates the liquid through a circulation flow channel which includes the common liquid chamber, the first flow channel, the sub-tank and the second flow channel; and a control section including a driving signal generating section which has circuits to generate ejection pulses and the control section is configured to sweep the driving frequencies of the micro-vibration pulses; wherein the driving frequencies of the micro-vibration pulses are swept between 1000 Hz to 1/(AL) Hz; wherein AL represents an acoustic length being one half of an acoustic resonance frequency of the plural pressuring chambers; wherein the driving signal generating section is connected with the electrodes and the control section controls the circulation device and the driving signal generating section so that the micro-vibration pulses are applied to the electrodes for applying a vibration to the circulating liquid in the common liquid chamber.