Power supplies, maybe, but you're going to need something around 30 - 50v at 10A+ and i doubt you'll find that in a printer or photocopier. Motors are harder, most printers/copiers use steppers but they are usually manufactured for the job and tend to be low torque motors. After all, moving a bit of paper or a scan head isnt a very arduous task compared to smashing a cutting head through a lump of hardwood...