GB977976A - Improvements in or relating to exposure devices for use in the production of contact copies by light and/or heat radiation - Google Patents

Abstract

977, 976. Exposure devices for photographic contact printing apparatus. W. ZINDLER, [trading as LUMOPRINT ZINDLER KOMM.-GES]. April 11,1961 [April 28, 1960], No. 13033/61. Heading G2A. An exposure device for use in the production of contact prints comprises a rotatable cylinder which transmits heat and light radiation, two different radiation sources located in the cylinder one being primarily a heat radiator and the other primarily a light source and an electrical control circuit which is operable to energize the light source only or both sources, the circuit including a main switch for the light source and a further switch for the heat operable only after closure of the main switch. This exposure device is preferably in a contact-printing apparatus which can use either light or heat-sensitive copy sheets. There may be a further light source in the cylinder and the heat radiator may be a filament lamp. As shown, the contact printing apparatus has a transparent cylinder 3 suspended in a moving endless belt 4 driven by roller 6. In the cylinder are two light sources 10 and 11, 10 emitting ultra-violet and 11 green light and a heat radiator 12 with a reflector 13. The original and copy sheet are fed in between plates 19 and 20 pivoting actuating element 22 which closes micro-switch 21 causing the heat-radiator to be switched on when the main switch 34 is closed. The light sources 10 and 11 are switched on and the belt 4 driven by depressing switch 34. When a heat-sensitive copy sheet is used, it and the original are guided by plate 14 on to the cylinder 3 and exposed by heat using radiator 12 and fed out through slot 17. When a lightsensitive copy sheet is used, it is fed with the original through slot 18 (see Fig. 6) or above plate 20 so that microswitch 21 is not energized and heatradiator 12 is not switched on. The assembly is exposed at 10 and fed out through slot 17. The exposed copy sheet is developed by a silver salt diffusion transfer device 27. This device 27 comprises a bath 28 with guide members 29 and a replenishment container 30 which maintains the liquid lead by hole 31. The bottom of container 30 also acts as the upper guide element. Specifications 922,595 and 935,428 are referred to.