A MEMS inkjet chip contains a large number of units. Each unit contains a piezo actuator, a pressure channel and a nozzle for ejecting the droplets.
All units are independently electrically actuated by an applied voltage. The electrostatic field causes a deformation of the piezoelectric material which in turn results in pressure waves and flow in the underlying unit filled with ink. The free surface at the nozzle end moves and a droplet leaves the nozzle.
Infinite has a long term experience with analyses in this field in cooperation with a major printer manufacturer.