i got my hands on two Seiko STP411 heat printing modules.
here is a picture of one
the printer where they came of is already gone.
there are no unsefull numbers or texts on these stepper motors, they only got 6 wires
i tried to use google etc to find some info about these stepper motors with no luck, i think dough they operate at around 5v amps unknown
is there a way to detect what type of stepper motor they are ?
Six wires would suggest that they are unipolar motors. That can be verified by measuring the resistances - each winding has a center tap. Resistance from each end to the center wire will be one half the total resistance of that winding. measure the resistance from each end to the center and from end to end.
Unipolar and Bipolar each have their advantages. I like bipolar because the wiring of a driver is simpler - just needs 4 transistors vs. an H-Bridge.
"I like bipolar" - surely that post only makes sense if you like unipolar?
Yes, I think its very likely to be 6-wire unipolar motor - the actual resistance will give a hint as to the voltage (the heat dissipated in the windings should be similar to other similarly sized motors for instance).
Some older stepper motors can be permanently damaged (demagnetized, remagnetized) if too high a current is used, so I'd err on a lower drive voltage (if it can't move the carriage then its clearly too low though !). I'd try 5V, if thats clearly not enough try 12V...