Improved Ink Shut Off Valve for Ink Jet Printers
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14
In ink jet printers it is mandatory that when the system calls for a shut-off, the ink supply being fed from the nozzle be quickly terminated so that no dribbling of the ink occurs onto the adjacent machine parts. Moreover the valving of the ink jet stream is a difficult problem because of hydraulic pressure surges (both positive and negative) in the drop generator occurring during valve action. A positive pulse or slow pressure decay on shut-down results in an ink puddle on the nozzle face while a negative pulse draws air into the fluid horn volume, resulting in unstable drop break-off on the next stream start-up.