We considered doing this too. The difficult part is getting even coverage of toner dust on the board so that you get uniform results. I'd be concerned that anything less than great coverage is probably going to yield lousy results. The other problem is that the ventilation in the laser cutter is going to want to blow around the toner, so you probably need some type of light adhesive to hold down the toner, and doesn't impede the toner setting process.
One method I just saw on the web was a guy that prints standard inkjet ink with a converted (to) flat-bed inkjet printer onto COTS copper clad, then dusts the board with toner, using the fresh wet ink as an adhesive for the toner. The board is then baked in a panini press (or any reasonable substitute) to set the toner. His results looked quite good, and gets your fixed costs down to a few hundred dollars, at the expense of higher marginal costs and more hands-on time & effort.
-e
Eric B. Wertz
> Could you maybe do an addictive process?
>
> I wonder what would happen if you spread a film of loose toner over
> the board and then used the laser to melt it where you wanted traces.
> Then dust the board off and etch. Might want a second heating with a high
> intensity lamp or some such to more firmly fuse the toner to the copper.
>
> I suspect this type of process would require a lot less energy than vaporizing
> something. It would also get away from possible problems of the copper reflecting
> the laser beam back into the laser and damaging it. IIRC copper is a really
> great reflector of infrared energy.
> Keith Bowers WB4LSJ- Thomasville, NC
>