Question about a motor from a printer

[Wildmine]

Hi!
I have a couple of motors i got from a printer and i don't understand what the top black cap is there for. Is it to measure speed or what?
This is the motor itself: Motor

I am thinking of making a CNC machine and therefor i am also wondering if i need any motor controllers/drivers to spin it both ways?

Thanks in advance!

 

[pwdixon]

Could be a stepper motor with that many wires if so you will need a stepper motor driver.

 

[ajofscott]

This is a commutated motor aka "brushed". The structure at the end is a daisy wheel for speed and position detection.