This very interesting approach to adding capabilities to a cheap 3d printer came into our inbox this week.
Aad Van Der Geest has been experimenting with a dual extruder setup that could bring full color printing to cheap filament based printers. His system utilizes 2 i3 style 3d printers merged into one. One extruder is a modified inkjet printer head.
As each layer is completed on the normal extruder, it then moves over and has a pass under the inkjet head, laying down the colors in CMYK for that layer. As you can see, this prototype is functional, but has a long way to go for the kinds of results people might expect.
Van Der Geest acknowledged that the current colors are lacking contrast, but points out that the proof of concept is functional. Now all that is left is refining the materials and process to get some really good results!