Toner chemistry
Any paint that I know of that you put into a 500°F oven is a phenolic. Remember those old kitchen parts that you used to put in the oven and they stunk and tasted weird. Or the old radio sets with internal parts that smelled.
There is a phenolic paint that when cooked off at 500°F will turn rock hard. California does not allow this paint however because the VOCs are off the chart. I used this paint on my heads of an old 6.9 liter Ford diesel. It effectively stopped the rust from doing anymore damage. I had to cook them on a BBQ because the heads were so big.
In color toner, I am sure the little color bits and pieces come from polyester resin parts. Polyester is a great thermoplastic and also is the source of the styrene, a cancer causing monomer. I have a polyester sprayer from Binks that is quite something. The plastic industry in California wants to cut the spraying out because again the huge amounts of VOC's that are sprayed out but the finish is a gel coat with granite like effect. The granite effect that was done with either an acrylic or a polyester with bits of color from bits of precast colored resin. It is quite the art and only a couple of companies makes those bits and pieces. If anyone is interested in a slightly used polyester granite effect sprayer and does not live in California I will sell it. I paid $6500 about 8 years ago, it has seen only about 20 hours of use. I will let it go for far less. If you heat a .100" thick layer of this polyester up, it has two distinct properties:
- It forms to any 3 dimensional object. That means you can wrap it around a pole and it will keep that shape when it cools. Its temperature is about 285°F at that "plastic point".
- It sticks to things.
I am sure it is not too much trouble to make the grain sizes even smaller for use in the toner. The FeO2 is rust in color and I cannot imagine why they use this other than its magnetic effects but at the temp the drum runs the magnetic effect is all but gone.
What you are talking about is that toner is a multi-blended structure. The waxes are obviously there to keep the stuff from sticking to the drum. Those waxes could be a hinder to having the foils stick. That seems to be the problem I see with the green foil like some little bits of something in the toner is not letting the foil adhere. I get superb coverage so that is not the issue. Another thing I am thinking about is that the silicon oil that the drum in the laser printer uses to keep the last film of toner from sticking could be getting little globs into the face of the toner as the oil would tend to float up. I think it may be worth to lightly wash the face of the printed image right after the print to get any waxes and any silicon off of the print.
I once painted a Porsche with a catalyzed paint. Right at the drivers side on the hood was a dimple where the paint did not stick. It, whatever it was, pooled around the paint and created onion ring effect. I had to sand down the whole hood again and prime it with an expensive alcohol based primer. That did the trick but was a puzzle why anything was in the hood preventing the paint from adhering.
I think the same thing happens here with the toner. Something that has no "sticktion" and is suspended on the top layers of the print. When the foil goes on, at the microscopic level, there is pin point of non adherence. The white foil seems to deal with this better than the green foil. It is your foils that create the chemical wall. If there are microscopic points where non adherence occurs this will create the bumpiness of the etch that I do not see in the PTS because the light is a little forgiving.
I would advocate that Puslar invest in an R&D department that creates it's own toner for it's favorite laser printer. Toner free of oils and waxes. The drum can be coated with some of the new techniques we have today that nothing will ever stick so maybe no need for the release waxes and oils. That also leads to modifying laser printers. I am sure if you prefect this, HP or some other manufacturer would be very willing to build these special laser printers for you at a licensed level. This assumes patents. Additionally, this of course assumes no one wants to build boards with the photo based system.
With the PTS, what I have done is to get light blocking negatives out of my laser printer. That is significant.