PURPOSE: To reduce residual vibrations, which inhibit the frequency stability of both the jet speed of ink droplets and the amount of ink droplets, make an ink jet head smaller in size and moreover accelerate the speed of droplets with respect to the same amount of droplets as compared with a conventional ink jet head by a method wherein the pulse width of an electric pulse is increased by specific function times, which function is related to the length of a pressure chamber and the rate of pressure wave.
CONSTITUTION: In this case, the pulse width of an electric pulse is set natural number times larger than 2L/Cs (provided that the length of a pressure chamber 2 is denoted by L and the rate of a pressure wave by Cs). On the wall surface of the pressure chamber 2 is provided an electromechanical conversion means 3 constituted of piezoelectric elements and the like, which vary the volume of the pressure chamber 2 by electric pulses (voltage pulses) applied to the electromechanical conversion means, and the pressure chamber 2 communicates to an ink chamber 4 to receive the supply of ink from the ink chamber. In an ink jet head having such a constitution, the volume of the pressure chamber 2 is rapidly decreased by the electric pulses applied to the electromechanical conversion means 3, and a positive pressure is thereby generated. This positive pressure is transmitted toward a nozzle 1 and the ink chamber 4.
KOMAI HIROMICHI
HIRATA TOSHITAKA
NAKANO TOMOAKI
KADONAGA MASAFUMI
IZUMI KOJI
