Patent ID: 6464336
Filing Date: 2002-10-15
Classification: B41J

Abstract:
A drop-on-demand ink jet printing system for delivering droplets of selectable-color ink to a receiver; the system comprising:a print head having at least one mixing chamber; a nozzle opening associated with each of the at least one mixing chamber through which nozzle opening ink droplets are delivered from the associated mixing chamber to the receiver; a plurality of sources of color liquid ink, each source (1) containing liquid ink of a different color and (2) communicating with the at least one mixing chamber; a source of bleach communicating with the at least one mixing chamber, and a flow controller adapted to selectably meter ink from said sources to the at least one mixing chamber, whereby ink droplets of selectable color are prepared in the least one mixing chamber for delivery from the nozzle opening to the receiver, the flow controller being further adapted to meter bleach into the mixing chamber after a droplet is delivered from the nozzle opening to thereby neutralize color ink remaining in the mixing chamber sufficiently such that a next desired color can be attained by adding ink of appropriate color to the mixing chamber.