InkJet & Toner Hybrid

This method of producting PCB's uses Etching to remove the unwanted copper from a pre-clab board, and a resist to prevent the removal where traces and pads should remain, just like all the other common Resist / Etch methods. The difference is that the resist is composed of melted toner, which has been dusted onto the board while the ink is still wet after the board has been run through an inkjet printer. The tonor sticks only to the areas where wet ink has been deposited by the inkjets.

The advantage over the toner transfer method is that the PCB is directly printed in the inkjet printer, resulting in higher resolution and quicker processing; no need to laminate, smear and peel. Traces/spaces as fine as 7 mil have been achieved. Toner transfer normally bottoms out at 10 mil.
The advantage over the direct inkjet method is that we do not need special pigment baised inks so any inkjet printer will do, assuming it can feed the PCB stock. Epson 200 series printers can be made to feed small PCBs without ANY modification by sending them though in the CD/DVDs printing tray.
The disadvantage of this method is that toner and paint dust are hazardous materials that may cause health issues. Update: Instead, use powdered rosin.^ Rosin is purified pine tree sap, and is generally non-toxic. Powdered version can be found online for ~$7 a lb.^

Epson 200 series printers can be made to feed PCBs, when the print head hight is adjusted all the way up, and the media is set to CD/DVD. In fact, with the thinner PCB materials, which are no thicker than a CD/DVD anyway, no modification is really needed.

Keeping the toner from sticking to the PCB where there is no ink:

Heat the board to make sure it is completely dry. Any humidity will increase the chance of stray toner dust sticking on the board.
Blow or Tap the board to remove extra toner.

rdheiliger says:

As to the ink drying before you can dust it with toner. On one of my test boards I left it on the bench overnight and it was still tacky the next morning. The photo papers they recommend for dye based inks has a top absorbent layer, designed specifically to hold the ink, and likely to help set it in a reasonable time. Since copper doesn't absorb the ink, you likely have a day to dust it.

Myc says: With a little dremel work on the CD tray to square off the circle, I was able to run an EAGLE sized (3" x4") 0.040" pcb. You an make a slightly smaller board with no modfication to the CD tray.

Myc says: Try electrostatic paint powder (availible at SEARS for about $6) instead of toner for a heavier and colored coating. {ed, this may allow soldermask and "silkscreen" component layout printing}

Jim KI6MZ says:

The usual way to harden the [toner] is to use heat (up to 400 degrees F). Here is a method that uses NO heat.

The toner consists of finely ground poly-ester resin. Acetone will dissolve this resin. In fact, Acetone solvent is the perfect way to remove the toner after etching. To FIX the toner to the PCB, without heat, in preparation to etch the board, take a table spoon of acetone and put it in a glass dish that can be covered and sealed. Put something in the bottom of the dish to place the PCB on face up. I use stainless steel bolts. Seal the dish with a glass pane or an acetone resistant plastic cover. Leave the PCB in the VAPOR of the acetone for at least 2 minutes. Remove the PCB and allow the acetone vapors to dissipate from the PCB (30 seconds). You can now touch the toner traces without damaging them and the PCB is ready to etch.

Questions: