| 摘要 |
PURPOSE:To perform gradation recording by making the size of an ink liquid droplet injected variable without changing the concn. of an ink, by driving a piezoelectric element by an electrical driving wave form constituted of the first pulse changing in polarity and amplitude or polarity and a pulse width corresponding to the size of the ink liquid droplet and the second pulse controlling the jet speed of the ink liquid droplet. CONSTITUTION:When the size of an ink liquid droplet injected is made large using ink having relatively high viscosity, an ink chamber 2 is contracted from such a state that the liquid surface at the end part of a nozzle is stationary by the first pulse 9 and subsequently restored to obtain a size larger than the diameter of the nozzle. When an injection size is made small, the ink chamber 2 is expanded by the first pulse 9 and subsequently contracted by the second pulse 10 to inject the ink. By this driving, the effective cross-sectional area of the nozzle becomes small to form the small ink liquid droplet. Therefore, when a piezoelectric element is operated by the drive wave form consisting of two pulses mentioned above, the size of the ink liquid droplet being injected also changes. |
