Homebrew PCBs

I've read they're great for making fpc's ... my previous employer had one and I can certify only that they're 100 no good for traditional toner transfer because the wax soaks straight into the paper when heated - perfect absorbtion

PG

---- Sent on an old timey phone. 'Scuse the typos etc.

-original message-
Subject: [Homebrew_PCBs] Phaser solid ink printersparently must come from the
 lower tray
From: "Mark Lerman" <mlerman@...>
Date: 25/03/2011 08:48

A couple of people on the list have mentioned using Xerox solid ink 
printers to make pcbs, so I thought I'd take a look. These machines 
print by depositing melted wax on a large rotating aluminum drum then 
rolling heated paper over the drum to transfer the image. This would 
seem ideal because the wax is an excellent etch resist so that you 
should be able to just print and etch. I bought a used Xerox Phaser 
8400 for $100 on ebay. My preliminary thoughts/observations:

1 - These are big, heavy machines, 65# (30Kg). They take up a lot of space.
2 - They take 20 minute or so to warm up and use (waste) a lot of ink 
when they start up.
3 - There is an incredible amount of system and component checking 
during the warm up period.
4 - There are a LOT of sensors, making it hard to force this machine 
to do things it wasn't designed to do.

That said, one simple way to use them is to print on thin pcb board. 
I ran a piece of ss .009 mil board through and got an excellent print 
right off the bat. I could simply glue this to a thicker piece of FR4 
and I would have a very simple method of making pcbs. I haven't 
etched a board yet, but others have said this is no problem. Since I 
don't have a lot of this thin pcb material, I don't want to etch 
right now, but I'll let you know.

After taking the paper path apart, I *think* I can straighten the 
path enough to run .062 board through, but I'm not 100% sure. There 
would certainly have to be a microprocessor to simulate a number of 
the sensors because there are quite a few paper sensors. In fact, the 
paper trays even have sensors that tell the printer how wide and how 
long the paper is as well as when the tray is empty! Another problem 
is that when the printer is first powered up it prints this very full 
page that must come from tray 2. Since the paper stops for awhile in 
the paper preheater before moving onward, the preheater (which has 
both entrance and exit sensors) has to be emulated in software.

Other problems are that every 50 pages the transfer roller is oiled, 
and every time there is an error the printer prints 'Chase" pages to 
clean off the drum.

Finally, there is the problem of preheating the board. A .062  pcb 
can fit through the preheater, but I have no idea whether it can heat 
the copper fast enough for the wax ink to transfer properly.

Lots of engineering challenges. I have put a data logger on the 
relevant sensors and will now try to make the printer print with 
emulated sensors. If that works, I can then see if full thickness 
boards can pass. I'll let you know!

Mark