Patent ID: 7234789
Filing Date: 2007-06-26
Classification: B41J,H05K

Abstract:
1. An apparatus for ejecting droplets comprising: a plurality of nozzles through which droplets are ejected; a plurality of liquid containing chambers each connected at one longitudinal end thereof with a corresponding nozzle; an actuator that changes a volume of each of the liquid containing chambers; and an actuator controller that controls driving of the actuator, wherein: the actuator controller applies, in accordance with a one-dot printing instruction, to the actuator an ejection pulse signal that increases the volume of the liquid containing chamber to cause ejection of a droplet, and subsequently only one additional pulse signal that increases the volume of the liquid containing chamber to pull back a part of the droplet about to be ejected; and a pulse width of the ejection pulse signal is A times a time T required for a pressure wave to propagate in one way longitudinally through the liquid containing chamber, where A is a positive constant less than 1, wherein the ejection pulse and the only one additional pulse signal generates a stable ejection of minute droplets.