| 摘要 |
PURPOSE:To effectively control the discharge amount of ink by providing ink discharge means using focusing operation of an ultrasonic wave, a vibrator for forming a curved shape to focus the wave, and discharge amount control means using a pulse modulation. CONSTITUTION:When a vibrator 1 is vibrated in a thickness direction at a high period, an ultrasonic wave radiated into an ink reservoir 11 is propagated toward an ink discharge port. Since the vibrator 1 is formed in a spherical shape, the wave is concentrated at the center F of the curvature of the vibrator 1. The wave concentrated at the center F generates a strong pressure at the port to raise the ink, thereby discharging an ink droplet 9. The discharged droplet 9 reaches a recording hair 8 to be fixed and printed. In this case, the wave modulated in a pulse width output from a low frequency oscillator 14 is radiated into the ink by the vibrator 1 by the oscillator 14 and a high frequency oscillator 15, and the discharging amount of the droplet 9 becomes proportional to the pulse width T of a pulse signal output from the oscillator 14. Accordingly, the discharge amount of the ink can be controlled by controlling the pulse width. |
