Multi-color printing using dye?

Has this ever been attempted? I was recently thinking about different methods of multi-head printing, but what if you can just some how integrate an inkjet nozzle to the very very end of the extrusion nozzle so that it will mix with a white plastic that is being extruded? I have no idea what type of ink would be best to use at these temperatures or how the ink will be managed, but hey maybe in a couple of years inkjet repraps will be a common option.

I recall someone mentioning the application of a Sharpie permanent marker to the filament as it entered the extruder. Perhaps a similar method, using multiple felt tips that can be automatically (or even manually, for simplicity) swapped at the print progresses would work. I do not remember how effective this method was at actually giving an even colour, but it is something that could be explored.

In case you haven't seen this experiment: [blog.reprap.org]

It's not what you are suggesting but similar. You could adapt this to inject dye to be mixed instead, though it does present a lot of problems no doubt.

Some time ago I did a crude experiment with a glass pipette with ink in it, when I touched the side of the pipette with a hot soldering iron a small amount of ink ejected.
The hot end could be the soldering iron and a solenoid could bring the pipette ( or equivilent devise) into contact, a crude sort of bubblejet, ?????????

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Random Precision