A piezo-electric transducer type pressure sensor such as a silicon pressure sensor or the like is provided in a low path of fluid located in the midway between a valve section and a nozzle ejection port in a fluid ejection gun. When foreign matters in the fluid block the nozzle and hence the ejection...http://www.google.es/patents/US4556815?utm_source=gb-gplus-sharePatente US4556815 - Piezoelectric device for detecting stoppage of a nozzle
Piezoelectric device for detecting stoppage of a nozzle
