Patent ID: 8015939

Claim:
An imprintable medium dispenser, comprising: a chamber; a nozzle; an actuator connected to the chamber and configured to be actuated and thereby generate a pressure wave within the chamber such that imprintable medium is dispensed from the nozzle; and a control circuit including a monitoring apparatus configured to receive a transient oscillation signal representing an oscillation of a structural part of the dispenser generated when the actuator is actuated and to monitor the operation of the imprintable medium dispenser by monitoring the transient oscillation signal, the monitoring apparatus comprising a computer configured to store a transient oscillation signal, configured to compare a plurality of parts of a waveform of the stored transient oscillation signal with a plurality of parts of a waveform of the received transient oscillation signal, and configured to initiate remedial action if one or more of the plurality of parts of the waveform of the received transient oscillation signal deviates from one or more of the plurality of parts of the waveform of the stored transient oscillation signal by more than a predetermined amount.