Oleds are not printed, at least not in a classical sense. They are made through wafer technology, just that a wafer is not silicone but some flexible conducting film (polymer). On top of it come few other slices of films and at the end a porous/transparent cathode. The "pixels" are made with vacuum depositioning, photolitography and etching. Just like a normal chip is made, in a (very) clean roomby joskk - Polymer Working Group
Was reading this thread with great interest. After some googling about cable drives i came across this patent i'd like to share. I don't own a 3d printer, though it's one big goal for the future. BRby joskk - Reprappers