There is a active thread at the moment entitled:
"Interesting article (direct laser printing, well... kind of)"
Referencing
http://www.smtnet.com/adsystem/redir.cfm?adid=1611I feel there would be interest by some with mixing this idea with
direct inkjet printing.
I don't recall this being discussed previously. Apologies if so.
What you end up with is direct inkjet printing onto 'Positive'
photosensitive PCB, the regular stuff you use currently with a
transparency photomask. There is very little cost (thrift) advantage
but it could very well solve a set of issues with being experienced
by the direct inkjet enthusists or those attempting small geometries
with photomask.
The idea is based on the premise that more ink varieties will adhere
to the photoresist as opposed to plain pure copper PCB material.
If the ink has problems sticking to the photoresist: it's game over!
I see the following advantages.
1. You do not have to bake the ink to make it etch resistant. After
printing, expose and develop the pcb as you would for the normal
photo process.
2. No need to sandwich a transparency and PCB between glass sheets
hence removing the problems when your sandwich fails to keep the mask
in intimate contact with the photolaminate.
There are a couple of points that need to be worked through.
1. Do most pigment inks adhere well to the photoresist?
2. Can dye inks adhere and provide sufficient UV opacity. This would
be a differentiator permitting other than epsons to be used.
3. The ink does not need to survive the developer stage but needs not
to intefere with it.
4. Will the ink adversely impact the longevity of the etchant
chemistry? (assuming that it dissolves during the etch process. Note
that if the ink disolves, the photoresist under the ink remains to
resist the etchant.) If the ink desolved in the developer stage - no
problem.
This idea does not bring cost savings to those wishing to aviod the
costs of Photo Laminate PCB material or the aging issues when there
is a long period between creating a PCB. It does expose pricey PCB
material (as opposed to a cheap transparency or tracing paper) to
your printer but may offer directinkjet developers an intermediatory
step when they are having troubles obtaining a tough ink after laying
down a good pattern.