MITSUMI M35SP-9P Unipolar, Bipolar or just Plain Depressed?

I have a MITSUMI M35SP-9P stepper motor which I salvaged from a printer. It has 4 wires so I assumed it was a bipolar motor. I connected it to the arduino using a SN754410 driver board, loaded up a bit of code to run it and all I got was a few jitters. So off to Google where I found a datasheet for it at http://www.mitsumi.co.jp/latest/Catalog/compo/motor/m35sp9_e.html. This describes the Excitation Method as a 2-2 Phase excitation (Unipolar driving) but no pinout. I have been searching all over Google but cannot find any clues at all. So does anybody have any idea on how to connect this motor up?

loaded up a bit of code to run it and all I got was a few jitters.

There are normally two reasons for this:- 1) You are trying to step it too fast - try slowing it down. 2) You have the coils connected in the wrong phase. Try swapping the winding of one coil.