Extremely flexible and nearly transparent circuits can be made using conductive fabrics. Here are some of the experiments I've done with conductive fabrics. They can be painted or drawn on with resist and then etched like a standard circuit board. Conductive glue or conductive thread is then used to attach the components to the fabric circuit board.
To make this clear, the inkjet printer is not used to directly print resist onto the fabric. Instead, it is only used to print the circuit design onto the conductive fabric. You will then have to hand paint a clear resist over the inkjet image before the circuit can be etched.
See step 1 for details on a printer that may work to directly print the resist onto conductive fabric.
Alternately--an inkjet printer is not necessary--you can just freehand paint or draw on the resist where you want the conductive traces to be.
Pic 1 shows a simple circuit that that lights 3 LEDs. I made some of the traces circular to find out if they would conduct well at angles to the warp and weft of the fabric.Materials
Performix (tm) liquid tape, black-Available at Wal-Mart or http://www.thetapeworks.com/liquid-tape.htm
Carbon Graphite, fine powder- Available in larger quantities at http://www.elementalscientific.net/
Available in smaller quantities at your local hardware store. It's called lubricating graphite and comes in small tubes or bottles.
Conductive thread-Available in small spools at: http://members.shaw.ca/ubik/thread/order.html
or at: http://www.sparkfun.com/commerce/categories.php?cPath=2_135
Conductive fabrics available from: http://www.lessemf.com/fabric.html
Clear Nail Polish
Ferric Chloride etchant available at: http://www.allelectronics.com/cgi-bin/item/ER-3/445/DRY_CONCENTRATED_ETCHANT_.html
or at: http://www.circuitspecialists.com/search.itml?icQuery=ferric+chloride
toluol solvent-available at hardware stores
Pic 2 shows the three conductive fabrics that were used in this instructable.
1-VeilShield-A mesh polyester plated with a blackened copper. Very light and 70% transparent.
2-FlecTron-copper plated nylon ripstop.
3-Nickel Mesh-Semi-transparent copper and nickel coated polyester.
pic 3 shows the back of the circuit and the glued components.