| 摘要 |
PURPOSE:To achieve stabilization of injection of an ink drop by preventing air from mixing into a nozzle operation by a method wherein an electric field crossing a passage is generated to a nozzle by using electroviscous ink, and pulse voltage having delay time synchronized with a piezo driving pulse of a piezoelectric element is applied. CONSTITUTION:Though electroviscous liquid ink has fluidity like water under a state of no electric field, it has viscosity like gelatin under presence of the electric field. When a piezoelectric pulse is applied to a piezoelectric element 16, an inside 12 of an ink chamber becomes firstly under a negative pressure state, and a meniscus is displaced to '-' side. However, since the piezoelectric element becomes again in a projected state to the ink chamber 12 side, the meniscus transfers quickly to '+' side. At this time, ink jets out from a nozzle 14, and is separated as an ink drop. Besides, pulse voltage is impressed to a pair of electrodes 18, 18 being delayed slightly from the piezo driving pulse. Though sucking ink into the nozzle 14 occurs successively after injection of the ink drop from the nozzle 14, the sucked ink becomes high viscous like a gelatin state due to electric field viscosity effect at that time. Consequently, air is never mixed in the ink by being introduced. |
