A method and apparatus for monitoring and regulating the ink droplet velocity in the ink supply system of an ink jet printer is proposed which essentially comprises an ink jet propulsion member, a charging electrode, a charge detector, a deflection electrode and an ink droplet catch gutter. In the method,...http://www.google.com.au/patents/US4612553?utm_source=gb-gplus-sharePatent US4612553 - Method for operational status checks of an ink jet printer
