Stitos,
Having tried with a portable oscilloscope, it is obvious that a much more fancy digital, recording piece of equipment will be necessary here.
All I have been able to confirm, so far, is that the pulse width is indeed 40uS and the Pulse Repetition Frequency at white is 0% increasing with shade to approx 90% at black but I have been unable to accurately measure the gap (pause) between the edges (join) of each pixel in the image but this does vary with feedrate.
Not much help really but I will try with another scope when time permits.
Tweakie.