FAULT DETECTION IN A MICRO MECHANICAL DEVICE

摘要

A method of detecting a fault within a micro electro-mechanical device in the form of an ink ejection nozzle having an actuating arm that moves an ink displacing paddle when heat inducing electric current is passed through the actuating arm and having a movement sensor associated with the actuating arm. The method comprises the steps of passing a series of pulses having varying duration through the actuating arm and detecting for contact of a moving contact element on the actuating arm with a fixed contact element. Normal operation of the device is indicated by no contact between the fixed and moving contact elements below a predetermined pulse duration and contact between the fixed and moving contact elements above the predetermined pulse duration.