Precision ejection ink-jet printing apparatus

摘要

A precision ejection ink-jet printing apparatus to prevent self-ejection. Self-ejection is an ejection of coloring agent particles from an ink-ejection opening without an application of ejection voltage to an ejection electrode. The precision ejection ink-jet printing apparatus includes an ink chamber filled with a pigment type ink, an electrophoretic electrode for causing coloring agent particles in the pigment type ink to concentrate at ink ejection openings, a plurality of ejection electrodes for causing ejection of the coloring agent particles concentrated at the ink ejection openings toward a printing medium, and voltage controller for controlling a voltage to be applied to the electrophoretic electrode. The voltage controller gradually increases the applied voltage up to a predetermined target voltage. The gradual increase in voltage moderates the electrophoretic motion of the coloring agent particles, preventing self-ejection.