Ever taken apart a standard bubble-jet printer? You will find gears, and tons of other little grooving things. Almost all of them can be "printed" but where it gets a hell of a lot more complicated is when it comes to electrics, as in motors and switches, and electronic components, as in the motherboard and printing head(s). While the motors and switches might be feasible in the near future I suspect that a motherboard full of integrated circuits, capacitors and resistors, a lot of them micro sized is well beyond reach for the moment. The only solution I can see is having the plans to print the printable parts but the motherboard and electricals and the printing head(s) would have to be part of a kit that one could order. But a completely self replicating 3D printer? For the moment I call it bull.