I had a thought to take a device such as this:

And replace the continuous flow ink containers with a jug of warmed emulsion. I have heard of biologists modifying printers to print biological material to glass, paper, etc (I am unsure what models they used). From what I have read this material they printed seems to have the consistency of emulsion. If possible this could create an easy to use system that makes perfect coatings on a variety of papers. I would think the emulsion would settle on the paper as well removing any trace of a dot pattern and papers could be run through for double coatings etc. This could be one possible future where we buy jugs of our favorite emulsions then simply use inkjet based technology to coat the paper. The ease of use would be the main attraction by making coating almost effortless with a high degree of quality control. Anyone care to give this a try? I'd have a play but don't have the time to research and modify a machine..