Patent ID: 7232199

Claim:
A droplet ejection apparatus comprising: a plurality of droplet ejection heads, each of the droplet ejection heads including: a diaphragm; an actuator which displaces the diaphragm; a cavity filled with a liquid, an internal pressure of the cavity being increased and decreased in response to displacement of the diaphragm; and a nozzle communicated with the cavity, through which the liquid in the cavity is ejected in the form of droplets in response to the increase and decrease of the internal pressure of the cavity; a driving circuit which drives the actuator of each droplet ejection head; ejection selecting means for selecting the nozzle of the droplet ejection head in the plurality of droplet ejection heads from which a droplet is to be ejected; detection determining means that determines for which nozzle of the droplet ejection head an ejection failure of the droplets is to be detected; ejection failure detecting means for detecting a residual vibration of the diaphragm in the droplet ejection head determined by the detection determining means and detecting the ejection failure of the droplets on the basis of a vibration pattern of the detected residual vibration of the diaphragm; and a plurality of switching means respectively corresponding to the plurality of droplet ejection heads, wherein, after carrying out a droplet ejection operation by driving the actuator corresponding to the nozzle of the droplet ejection head determined by the detection determining means, the switching means corresponding to the determined droplet ejection head switches a connection of the driven actuator in the determined droplet ejection head from the driving circuit to the ejection failure detecting means, wherein the detection determining means repeatedly carries out a scanning operation in which any one of the plurality of switching means is sequentially scanned in a predetermined order, determines the droplet ejection head as a droplet ejection head for which the detection of the ejection failure of the droplets is to be carried out when the timing of the droplet ejection operation of the droplet ejection head coincides with the timing of the scanning of the switching means.