A method of detecting a leak in an ink delivery system comprises providing an ink delivery system having a plurality of pipes, wherein the ink delivery system could potentially have an ink leak producing an audible signal. The method further comprises providing an ultrasonic detector operable to detect the audible signal and actuating the ultrasonic detector to detect when the ink leak is present by detecting the presence of the audible signal. Finally, the method comprises outputting a signal when the audible signal is detected to alert a user.