I did not get constant results with the gel backing printing method. I think the main reason was that humidity would change between when we had our etchent bath running or not. What I eventually ended up doing was: Use a conductive carrier. Ground it with finger stock from the bottom. Connect the copper of the PCB material to the carrier electrically by taping on a few fine wires. Using this technique I was able to get really good prints consistently, it does not seem to very with humidity, and we don't have to worry about applying a messy gel to the board.
Message
Method for direct laser printing.
2011-12-28 by michaelnoelme90