| 摘要 |
To enable fine droplets each having a diameter of 15 mum or less to be ejected without causing increase of device cost and a device size, and decrease reliability and a manufacturing yield. A driving waveform driving a piezoelectric actuator comprises a first voltage changing process 31 for inflating a pressure generating chamber in a falling time t1, a second voltage changing process 32 for rapidly deflating the pressure generating chamber in a rising time t3 after keeping the fallen voltage during a time t2, a third voltage changing process 33 for rapidly inflating the pressure generating chamber just after the preceding process, 21Q and a fourth voltage changing process 34 for compressing the pressure generating chamber just after the preceding process. Hereat, t1 and t2 are set so as to satisfy the following expression:t2=t0-t1 <math-cwu id="MATH-US-00001"> <number>1</number> <math> <mtable> <mtr> <mtd> <mrow> <msub> <mi>t</mi> <mn>0</mn> </msub> <mo>=</mo> <mrow> <mfrac> <msub> <mi>T</mi> <mi>c</mi> </msub> <mrow> <mn>2</mn> <mo>⁢</mo> <mi>pi</mi> </mrow> </mfrac> <mo>⁢</mo> <mrow> <mrow> <msup> <mi>tan</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mo>⁡</mo> <mrow> <mo>[</mo> <mfrac> <mrow> <mi>sin</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mrow> <mfrac> <mrow> <mn>2</mn> <mo>⁢</mo> <mi>pi</mi> </mrow> <msub> <mi>T</mi> <mi>c</mi> </msub> </mfrac> <mo>·</mo> <msub> <mi>t</mi> <mn>1</mn> </msub> </mrow> <mo>)</mo> </mrow> </mrow> <mrow> <mrow> <mi>cos</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mrow> <mfrac> <mrow> <mn>2</mn> <mo>⁢</mo> <mi>pi</mi> </mrow> <msub> <mi>T</mi> <mi>c</mi> </msub> </mfrac> <mo>·</mo> <msub> <mi>t</mi> <mn>1</mn> </msub> </mrow> <mo>)</mo> </mrow>
|
