Drop Velocity Servo In An Ink Jet Printer
Original Publication Date: 1979-May-01
Included in the Prior Art Database: 2005-Feb-20
In ink jet printers wherein a continuous ink stream is ejected from a nozzle, selectively charged in a charge electrode and then the ink drops are deflected due to the field caused by deflection electrodes, it is mandatory that pump pressure and, therefore, that of the ink stream itself be calibrated correctly so that drop deflection height and therefore character height on the ink drop receiving medium (paper) is correct for printing characters. For example, if an ink drop with a predetermined charge thereon is travelling too slowly, its residence time intermediate the deflection electrodes will be longer, increasing the effect of the deflection electrodes on the drop and, thereby, increasing its deflection height.