| 摘要 |
PURPOSE:To prevent effectively the decrease in jet speed following the increase in volume, by generating the pressure pulse having sharp top and rear parts and the inclination part the amplitude of which increases as time elapses between those both end parts in ink. CONSTITUTION:The sharp fall part of a voltage pulse P immediately appears in a lead wire 21 via a capacitor 32. If the electrostatic capacity value of the capacitor 32 is made approx. the same as the electrostatic capacity value of a piezoelement 20, the voltage pulse P sharply falls to the amplitude of approx. one half thereof. When the sharp fall following the charge of the capacitor 32 has ended, the voltage value of the voltage pulse P increases as time elapses at the time constant determined by the product of the electrostatic capacity value of the piezoelement 20 and the resistance value of a variable resistor 33. Thereafter, when the voltage pulse rises (returns), the capacitor 32 and the piezoelement 20 are suddenly discharged via a diode 34 and the voltage pulse P sharply returns. Therefore, the voltage pulse P shows the waveform having sharp rise and fall parts and the inclination part the amplitude of which increases as time elapses in its midway. Thereby, the decrease in jet speed following the increase in volume comes not to be generated. |
