Ink-jet head, ink jet printer, and its driving method

摘要

An ink-jet head ejects an ink droplet from an ink nozzle by the charging and discharging between a counter electrode and vibrating plates. The counter electrode comprises a main electrode and an auxiliary electrode, which is provided on the ink-nozzle's side in common with the vibrating plates. Auxiliary charging between the auxiliary electrode and the vibrating plates is effected to vibrate a meniscus in the ink nozzle without ejecting a useless droplet. Consequently, the ink is prevented from forming a film on the meniscus, and an increase of the viscosity of the ink due to evaporation of the ink solvent is prevented by diffusing the ink in the ink passage.