Patent ID: 7108348

Claim:
A droplet ejecting apparatus comprising: a droplet ejecting head including: a vibration plate; an actuator for displacing the vibration plate; a cavity filled with a liquid and having an interior pressure to be increased and decreased by a displacement of the vibration plate; and a nozzle communicating with the cavity and for ejecting the liquid as a droplet depending upon an increase and decrease of the pressure within the cavity; a drive circuit for driving the actuator; and an ejection abnormality detecting device having a residual vibration detecting device for detecting residual vibration of the vibration plate displaced by the actuator after the actuator is driven by the drive circuit, to detect an abnormality of droplet ejection depending upon a vibration pattern of the residual vibration of the vibration plate detected by the residual vibration detecting device, the ejection abnormality detecting device including a determining device for determining a presence or absence of a droplet ejection abnormality of the droplet ejection head depending upon the vibration pattern of residual vibration of the vibration plate; wherein the determining device determines a cause of the ejection abnormality when the presence of a droplet ejection abnormality is determined; wherein the vibration pattern of the residual vibration of the vibration plate includes a period of the residual vibration; and wherein, when the period of the residual vibration of the vibration plate is shorter than a predetermined first period, the determining device determines that the cause of the droplet ejection abnormality is that there is an air bubble mixed in the cavity.