| 摘要 |
PURPOSE:To enable ink droplets to be discharged stably by providing a means to apply a magnetic field to ink in a head after discharging ink droplets. CONSTITUTION:If a pulse voltage is applied to a piezoelectric element 2, the element 2 contracts to increase pressure in a pressure chamber 1 and discharge ink droplets from a nozzle 3. If a drive current is applied to coils 6a, 6b after driving the element by a voltage pulse, a flux generated by the current passes through a yoke 5 to generate a magnetic field which pierces a head body 4. For this reason, magnetic particles of magnetic ink in the pressure chamber 1 are caught by the flux, so that their position is restricted. This causes a relative speed difference to a solvent and the magnetic particles, thus dispersing oscillation energy by the viscosity of the solvent and allowing the residual oscillation of pressure to reduce rapidly. When the residual oscillation of pressure has diminished, a drive current is switched OFF to cut off a magnetic field applied to the head body 4. After this process, the stable discharge of ink droplets is allowed at arbitrary timing. |
