Drying concentration of photographic emulsion coating by microwave irradiation

摘要

A photographic emulsion coating on a travelling web 1 is irradiated by microwave energy propogated through a slotted, undulating waveguide 5 to condense or concentrate the coating by evaporating a significant percentage of its water content, thereby shortening the overall drying time for a given coating rate. A forced flow of air and/or other gases is established through apertures 9 in the waveguide under controlled temperature and humidity conditions, and the internal heating effected by the microwaves prevents the formation of a surface film which might impede subsequent drying.