Abstract: An improved developing apparatus for diazo-type photocopy machines, which is adapted to prevent external leakage of gaseous ammonia developing medium to the surrounding environment is provided. The apparatus comprises a developing chamber having transport means for advancing exposed diazo-type sensitized paper therethrough, means for introducing and circulating gaseous ammonia within the chamber to develop an image on the sensitized paper; and a vacuum pump for evacuating said ammonia from the developing chamber. As an additional feature of the invention, vacuum surge means are provided to maintain the below atmospheric pressure within the developing chamber at a relatively constant level to ensure uniform development of the sensitized paper.

Abstract: In a diazo-type copying apparatus, an improvement to prevent external leakage of gaseous ammonia to the atmosphere. The apparatus comprises a developing chamber, transport means within the chamber, means for introducing ammonia gas to the chamber, a first enclosure enclosing the chamber for sealing it from the atmosphere, a second enclosure containing the first enclosure as well as a perforated vacuum tube for collecting ammonia gases escaping from the first enclosure as well as for scrubbing ammonia gases from developed copies and exhausting the gases either to a liquid ammonia absorbing solution, a filter containing an ammonia absorbing solution, a cartridge containing ammonia absorbing pellets or a catalytic converter thereby preventing the ammonia gases from contaminating the atmosphere.