Keeping flat would be easy for the Epson 3000, but I don't know if you could keep the temp up to 110 while it flies through the air before it hits the paper. You might have to build a heat box so that the air temperature is up at 90-110 or hotter, and there could be some problems with the heads at this temp, but it's kind of unlikely to be a problem. You may want to pre-heat the paper too, but that might be easy with some of the electric heaters on the market. Just run it over a heater bar as it unspools from the roll before it goes into the heater box.
What solvents are used in this process? Is it just water or something more volitile?
I wonder what it would take to get a chilled bar on the output of the printer to rapidcure the paper?
The required silver per unit area may be much harder to obtain with the very thin viscosity needed to spray this. The viscosity of modern pigment inkjet inks for Epson printers is only slightly thicker than water, and I do mean slightly. Wish I remembered the actual value but probably only .05 thicker, safe to say the same as water.
Would it be easier to make an automated blade coating machine that would take roll paper or large sheets? Seems like it should work similar to the way ink is transferred from the well to the press rollers on a printing press. Maybe a hybrid where the thicker goop is pumped through spray nozzels in a constant stream, then a blade to smooth the goop into a uniform layer. Then a rapid dry section near the output of the machine. You could precisely regulate the amount of sprayed goop so that there was minimal waste coming off the sides of the blade. If you heated the spray nozzels, and the rollers, and maybe the paper, this seems like it would be a better design. And yes I know I am probably reinventing the paper coating machines that (may) still be used today. I think this is a more viable machine for this task.
Is this an all dark process, or can it be in light until the goop cures/dries? What about IR and near IR light? A radiant heater might speed up the process so that it is a dry to dry process, else you might need to use the contact heaters to rapid dry the paper.