some printers have what is called a continual inking system ( a large tank with tubes to feed the printer, instead of the cartridges )
i wonder if this might be adapted for such a system to hold liquid emulsion, instead of the tiny 1.5ml tanks.

Yes it could, but insulated jackets would be needed to keep the emulsion hot, and the large reservoirs must also be kept hot. This is how it is done in production. The hopper on a coating machine is the 1.5 ml tank and the feed is coming from stainless tanks that are jacketed and heated. The lines going to the hopper are kept at the same temperature otherwise the gelatin will set up in the lines or the viscosity will go out of control.

PE