GB686990A - Improvements in or relating to apparatus for developing photographic images - Google Patents

Abstract

686,990. Photographic vapour-developing apparatus. OZALID CO., Ltd. Oct. 12, 1950 [Aug. 11, 1949], No. 20949/49. Class 98 (ii). Vapour producing means are controlled electrically by a detector device responsive to the passage of sensitive material to a development zone so that vapour production is active only when such material is passing. Spring contacts, so responsive, in an electrical circuit, may control an electro-magnetic regulating valve in the means. As shown in Fig. 1, ammonia solution from reservoir 32 passes by way of unit 33 comprising the valve to a distributer tube 23 where it is vaporized by electrical heating element 25, the tube and element being inside a chamber having a perforated wall 13 outside of which exposed material is traversed by rubber conveyer belt 15. In introduction into the nip between the conveyer belt 15 and the lower part of the perforated wall 13 the exposed material is caused to pass between two support members carrying electrically insulated spring contacts 42, 43, which are arranged in pairs, and are opened by the material; and when the contacts are open the valve in unit 33 is open to permit passage of the ammonia solution. Fig. 3 (not shown), indicates the circuit arrangements. A by-pass for unit 33 may provide a small uninterrupted supply of ammonia to maintain concentration in the chamber. A thermostatic switch may be included in the circuit to prevent opening of the electromagnetic valve until the chamber attains a particular temperature. Specifications 495,392 and 686,991, are referred to.