Re: Re: Test Peice for 3D finishing

Ian,

The polygon mirror is a front-surface(means the shiny stuff is on the
front surface to eliminate refraction errors)reflector used to
provide "scanning" of the laser beam.

The mirror is rotated at a fixed speed and the laser beam is pointed
at it. The beam is deflected by the rotating mirror in a precise
linear manner. At each vertex(of the mirror) the beam "resets" to the
beginning of the "scan" line. So the effect is the same as shining a
flashlight from side to side repeatedly.

In a laser printer, this "scanning" beam charges(or discharges) the
surface of the "drum"(the photosensitive cylinder upon which the image
(later transferred to paper)is "developed"). Since the drum is also
rotating at a constant speed, the net effect is that "lines of info
(the laser is modulated i.e.,turned on and off)are placed onto the
drum in the form of electric charges.

These charges are used to attract the toner(which makes the pattern
of the original image) to the drum; then the toner image is
transferred to the paper and "fused" with heat and/or presseure.

Hope this helps.

Ballendo

P.S. This answer could have been shorter. Do you(on the list) want
the additional info, or just the facts, mam?

<snip>I had just dismantled the laser assembly and in it is an

>accurate hexagonal mirror. Seeing this his eyes lit up...

<snip>as 'a polygon' and was muttering about 'collimating light

>beams' and such like. Perhaps this could be a source of an accurate
>set-up tool - maybe used with one of the 'pocket laser pointers'? Or
>is this all just rubbish??? ;o)
>Ian W. Wright