Patent ID: 6568799
Filing Date: 2003-05-27
Classification: B41J

Abstract:
A drop on demand ink jet printing system for controlling delivery of inks to a receiver; said system comprising:an ink flow chamber having (1) a nozzle opening in a wall of said flow chamber through which ink droplets are ejected when ink in said flow chamber, at the nozzle opening, is at or above a predetermined positive pressure, (2) an inlet channel opening into said flow chamber and adapted to transport ink into said flow chamber at or above said predetermined pressure, and (3) an outlet channel communicating said flow chamber with a low pressure ink reservoir, said outlet channel being adapted to normally transport the ink from said flow chamber at a flow velocity sufficient to maintain ink in said flow chamber, at the nozzle opening, at a pressure less than said predetermined positive pressure; and a valve associated with said outlet channel and adapted to selectively restrict the flow of ink through the outlet channel sufficiently to cause an increase in ink pressure in said flow chamber, at the nozzle opening, to at least the predetermined positive pressure, whereby an ink droplet is ejected through the nozzle opening.