The droplet ejection apparatus of the invention includes a plurality of
droplet ejection heads 100 each having a diaphragm, an actuator that
displaces the diaphragm, and a nozzle through which a liquid in a cavity
is ejected in the form of droplets in response to the increase and
decrease of the internal pressure of the cavity, ejection selecting means
182 for selecting the nozzle of the ink jet head 100 in the plurality of
ink jet heads 100 through which a ink droplet is to be ejected, ejection
failure detecting means 10 for detecting a residual vibration of the
diaphragm and detecting an ejection failure of the droplets on the basis
of a vibration pattern of the detected residual vibration, and switching
means 23 for switching a connection of the actuator from a driving
circuit to the ejection failure detecting means 10 after carrying out a
droplet ejection operation by driving the actuator.