Using stepper motors with integrated controllers
Many of the motors that look like stepper motors in laser printers are actually three-phase brush-less DC motors.  These look like stepper motors, but are intended to be used differently, controlled differently, and serve a different function.  Like stepper motors, they have a permanent magnet rotor surrounded by coils of wire.

They typically are used in applications that require a definite rotation speed, rather than a definite position -- velocity rather than location. They create feedback to their controlling board via an encoder.

Differences include having a smaller number of poles, and possibly having three coils rather than two.  I suspect that the magnetic field profiles of the poles may also be different, since the primary design purpose is not to sharply define the restoring torque curve for a small deviation of the rotor from a rotational position.

If these are the type of motors you have in hand, you won't find them very useful for a 3D printer motion control system.  They are great for any form of continuous movement where position isn't critical -- maybe wheel motors for robots or for peristaltic pumps on your automated drink mixer.

You may ask on what experience I speak.  I have done tear-down analysis of several laser printers by different manufacturers.