Gelatin based emulsions harden as they cool, so it might work for a minute or so before the heads and feed tubes get clogged up, presuming the emulsion isn't too viscous to get through the print heads in the first place. I suppose the heads may stay hot enough to keep the gelatin liquid, but I think the feed tubes would clog before you could coat a large sheet evenly.
Sounds like a roadblock but not a show stopper. The containers, tubing and heads will have to be maintained at a certain temp. Might be best to have the container and the head in one piece that is kept warm. Also custom heads may need to be developed. Now who has a few million for R&D?