Patent ID: 6568795
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 channel having a nozzle orifice in a wall of said ink channel through which ink droplets are ejected when ink in said ink channel is subjected to a momentary positive pressure wave; an ink feed passage opening into said ink channel and adapted to transport ink into said ink channel from an ink reservoir, wherein: said ink feed passage comprises an microfluidic channel; a selectively-actuated valve associated with said ink feed passage and adapted to restrict the flow of ink through said ink feed passage when actuated, said selectively-actuated valve comprises a heater in thermal contact with at least a portion of the associated microfluidic channel, whereby thermally-responsive ink in said ink feed passage can selectively be heated by said heater such that the thermally-responsive ink will be caused to increase in viscosity to thereby restrict ink flow through the ink feed passage; and a controller adapted to actuate the valve in timed association with the momentary pressure wave, whereby flow of ink past the valve from the ink channel towards the reservoir is inhibited.