Can a printer print without using ink?

I was thinking about thermo-printers and I had a zen-moment: how about a printer that simply burns small dots in the paper, using only light (lasers?) and no ink?
Could it work?

The result would be a potentially very small b/w printer, that never runs out of ink and can print on normal paper...

Here is another guy that thought the same thought (before me of course! :D ).

And remarkably enough Polaroid and Zink are making an ink-less color printer (but they cheat, because the paper is special and has chemicals already in it!). Check it out: here, here and here.

Bye.