Xerox’s process uses ink containing silver metal that can be used to wire up processing circuitry. It works on surfaces such as plastic that earlier have shown an inconvenient tendency to melt under the high temperature of liquid silver; Xerox’s process works with an ink compound with a much lower temperature, the company said.
The technology uses conventional inkjet printing methods, and though Xerox has used it with conventional desktop printers, the company expects that it would use continuous-feed printers that print on rolls rather than sheets of material. It doesn’t require the super-clean environments needed for conventional silicon chip manufacturing. The Xerox process actually requires printing three layers on a substrate: a semiconductor, a conductor and a dielectric. The silver ink is the layer that conducts electricity.
Xerox develops conductive ink for printable circuits - [Link]