His name is Karol (it’s Charles in English) has said “A ploter described here writes on dark plastic things with a DVD-RW laser diode. I did not made the mechanism with stepper motors which you can see on the photos below, I got it whole as it is and I don’t know where it comes from. With a complete and working moving table I had to build a driver for it. There was two solutions: make a simple transistor buffer to connect motors coils directly to LPT port and write a control program for my own, or make more complicated motor drivers with step/dir inputs and use one of commercial control programs, for example Mach2. I choosed the first solution, it was faster for me to write a simple program than to build complex motor drivers 
Electronic part of this project isn’t even worth drawing a schematic, becouse it’s only nine NPN transistors: eight to drive the motors and one for turning laser on and off.”
