GB733641A - Improvements in or relating to photographic contact printing machines - Google Patents

Abstract

733,641. Photographic contact-printing apparatus. WENDT, O. June 20, 1952, No. 15594/52. Class 98 (2). In a photographic contact printing machine having at least two interchangeable pressure members each having a glass presser plate, one of the presser members is so constructed that the glass holds the negatives or the like in contact with the printing plate on a supporting table by the application of external pressure, and another pressure member is constructed for the production of a vacuum between the glass presser plate and the printing plate, means being provided at fixed positions on the machine for guiding and supporting either pressure member. As shown in Fig. 1, the pressure member 1 carrying the glass presser plate 13 for transmitting external pressure is located by guides 2 in a fixed frame 3. The member 1 is preferably square with the guides 2 at the mid-points of its sides. A spring frame 8, bearing by rollers 11 against blocks 12 on the frame 3, carries springs 7, adjustable by nuts 9 on spindles 10 and pressing member 1 and plate 13 against a negative 18 and a light-sensitive plate 5 on a fixed support. This arrangement is useful for smaller negatives; for larger negatives the member 1 is replaced by a member 1a, Fig. 2, carrying a glass plate 14 surrounded by sponge rubber sealing strips 15. The member has channels 17b connected to a suction pipe 17 and registering with apertures 15a in strips 15, to create a vacuum between glass plate 14 and the light-sensitive plate 5.