METHOD AND APPARATUS FOR EVACUATING AQUEOUS AMMONIA VAPOR FROM FILM DEVELOPING CHAMBERS

A diazo film developer which has a developing chamber that is kept at a temperature above the dew point for the film. Feed rollers disposed adjacent an intake opening of the chamber are maintained at a temperature above the dew point and advance film to be developed to the chamber. Exit rollers at an outlet opening for the chamber withdraw developed film from the chamber. The rollers are sealed with respect to the chamber to prevent the escape of aqueous ammonia vapors. The portion of the exit rollers disposed outside the chamber is subjected to relatively low temperature airstream to cool the rollers below the dew point for the aqueous ammonia vapor. The exit rollers are continuously rotated so that aqueous ammonia vapor can condense on surface portions of the rollers disposed interiorly of the chamber. The condensate is then transported by the rotating rollers to the exterior of the chamber and the cooled airflow removes, e.g. evaporate the condensate before it is re-introduced into the chamber.