Homebrew PCBs

A subject dear to my heart!

I have spent the last six months experimenting with direct laser 
printing of PCBs, and I am now able to (fairly) reliably produce 
boards using this method. If anyone is interested I can share a LOT 
of details, but the Brother is NOT the way to go. I spent a month or 
so working with the HL-2170, as well as a few other false starts 
before settling on the Lexmark E260 as the printer of choice. The 
"straightness" of the path is relative, and all of the laser printers 
have to be modified to pass pcbs, although you can run the thin, 
somewhat flexible (eg 8 mil) boards through some of them. You cannot 
use the internal fuser.

When I described some of my earlier efforts at direct laser pcb, 
there was some concern that the drum is too easily damaged. In the 
past months I have made several hundred "runs" through my modified 
printer, many of which were experimental, without proper smoothing 
and protecting of edges, and I am still using the same drum. I am 
still not sure of the limits of the process, but I have produced 5 
mil traces without problems.

The steps are:
1 - Produce the artwork - I use Eagle.
2 - Print the pcb.
3 - Place board in oven to "fuse".
4 - Etch.

One real advantage of direct laser pcb is that you can see the 
results instantly, and if the "image" is not perfect, you can just 
brush the toner off, wipe the board with acetone, and do another run!

I was waiting till I had the process perfected before "publishing" on 
this forum, but if anyone is interested, I can provide details. You will need:

1 - A Laser Printer - I strongly recommend the Lexmark E260, on sale 
at Staples for $169 (?) with an additional $50 off if you bring in 
any dead printer for "recycling".
2 - A high voltage power supply to provide a variable Transfer 
Voltage. A 3KV (variable) at 100 microamps will do - Ebay is your friend.
3 - A high voltage relay to switch between the internal transfer 
voltage and the external supply is useful but not strictly necessary.
4 - A simple microprocessor board to spoof the sensors that need to 
be emulated and control the printer solenoids and such.

Mark