PURPOSE: To stably form ink particles having different particle diameters, by a method wherein, in a charge deflection control type ink jet recorder, a voltage, applied to an electrostriction vibrator providing pressurized ink with vibration, changes at every cycle.

CONSTITUTION: Pressurized ink fed to a nozzle cylinder 1 is surged by an electrostriction vibrator 2 of the nozzle cylinder 1 applied with an exciting voltage and is separated into ink particles through a nozzle 1a. In this case, the surge of voltage applied to the electrostriction vibrator 2 is caused to change its amplitude at every cycle, and thereby ink particles having a large diameter and ink particles in a small diameter are formed alternately. In the same manner, when the amplitude of the exciting voltage is varied sequentially with every cycle with more than 2 cycles as a unit, particles having classifications in particle diameters of more than two different kinds are formed at every cycle. Further, by adjusting the height of the overall levels of the exciting voltage, adjustment of particle diameter ratio of the larger particles and the smaller particles can be made possible.