Some of you might find this interesting:
http://www.newscientisttech.com/channel/tech/dn11632-modified-ink-printer-churns-out-electronic-circuits.html
It's an article about inkjet printers being used to print conductive
traces, directly, onto many different types of materials, using a
silver nitrate solution, followed a few minutes later by a reducing
agent (they mentioned using a Vitamin C solution), and then washed with
water to leave only the metal traces.
I haven't investigated it any further than that. I just thought some
of the people here might like to know about it.
- Tom Gootee
http://www.fullnet.com/~tomg/index.html-