Numerical calculations are performed to investigate the effect of the component of a single transducer pulse on the ejection of a drop for a drop-on-demand ink-jet printhead with a piezoelectric actuator. The flow field is governed by continuity and Navier-Stokes equations. A volume-of-fluid method with a piecewise-linear interface construction is used to track the complicated topological variation of the liquid-gas interface. The computer code is validated with experimental results present in the literature. The volume of the primary drop is closely related to the maximum displacement of chamber wall induced by the piezoelectric actuator in the forward stoke; the velocity of the primary drop depends on the ratio of to the time period of the forward stoke . Moreover, the fact that the formation of the primary drop depends weakly on the conditions of the backward stroke is considered. A decreased interval between forward and backward strokes might serve to suppress the formation of satellite drops owing to reducing the liquid thread length at pinching off to a value less than the upper limit . The breaking up of the freely flying liquid thread from nozzle outlet has two modes—multiple breaking up and end pinching—and depends on the thread length at pinching off.