Purdue researchers have developed a method of recognizing unique patterns specific to each printer regardless of print cartridge used. Edward J. Delp, Jan Allebach, and George Chiu developed software to recognize intrinsic signatures revealing the subtle differences from one printer to another. A second step involved extrinsic signatures from specially designed printers for purposes of identification. (via Engadget) Counterfeiters could be traced back to their printers but you would need to have the equipment on hand to compare. I doubt we will ever have to register our printers upon purchase but unless you are paying cash your new printer is already tracked.