Patent ID: 6523923
Filing Date: 2003-02-25
Classification: B41J

Abstract:
An ink ejection apparatus, comprising:a nozzle from which ink is ejected; an ink chamber provided on a back of the nozzle where the ink is stored; an actuator that changes a volume of the ink chamber; and a drive device that drives the actuator by applying a drive signal including a plurality of pulses to the actuator to cause the actuator to generate a pressure wave vibration in the ink chamber, thereby ejecting three or more separate ink droplets from the nozzle, wherein the drive device generates positive and negative pressure waves in the ink chamber through application of each drive pulse to the actuator; and, when the three or more ink droplets are ejected for one printing command and when a crest value of a voltage applied to drive pulses P1, P2 and P3 is substantially fixed, the drive signal satisfies following expressions: 0.8T&lE;T1&lE;1.2T, 0.4T&lE;T2&lE;1.2T, 0.4T&lE;T3&lE;0.8T, W1>W2, and W1>2T, T1 is an effective pulse width of a drive pulse P1 to eject a first ink droplet, T2 is an effective pulse width of a drive pulse P2 to eject a second ink droplet, T3 is an effective pulse width of a drive pulse P3 to eject a third ink droplet, W1 is an interval between a start of the drive pulses P1 and P2, W2 is an interval between a start of the drive pulses P2 and P3, and T is a one-way propagation speed where a pressure wave is propagated in the ink chamber once.