Patent GB-881029-A (GB)
Title: Photographic printing apparatus
IPC: G03B27/02
Filed: 1960-01-29
Abstract: 881,029. Contact printing and developing apparatus. TECNIFAX CORPORATION. Jan. 29, 1960 [March 3; 1959], No. 3229/60. Class 98(2). A contact printing apparatus comprises an exposure chamber having an illumination source .therein, a slot allowing communication with the interior, a transparent plate and a further plate which can be detachably secured together and between which are placed the light-sensitive film and the original, the plates and the sheets enclosed therebetween all being in registered relationship, and removably insertable as a unit through the slot into the chamber, with means inside the chamber for engaging with the transparent plate and so pressing the film and original together in readiness for exposure. The chamber is in the form of a box 10 of light-weight material, and lined with highly reflective panels 82, 83. The box stands on a rubber pad 24, separated from the base-plate 28 by a cork filler 26, it being intended that the whole apparatus is light enough to be readily transportable. The light source is a flood lamp 25, preferably having a high proportion of ultra-violet, and is switched on for a pre-set time, together with a cooling fan 86, by a timer 21. The so-called "compression assembly" is shown in exploded form in Fig. 4. It is built up on a base board 42 carrying three registration pins 54 at one end. On this is mounted an adapter tray 44 having holes 62 corresponding to registration pins 54. The upturned edges 64 of this tray locate a foam rubber pad 46. On this is mounted a white interleaf card acting as a reflecting backing for the light-sensitive film 74 which is superimposed on it. On the film is laid the master sheet 58 carrying the drawing or design to be photoprinted. A glass plate 49 completes the assembly. Each component except the final glass plate has three registration holes corresponding to the pins 54. When they have all been assembled, with the glass plate uppermost, the assembly is ready for printing, and is slid through slot 20 into the exposure box, as shown in Fig. 3, suitably placed guides holding it in the correct position. Rollers 78, two at each side of the box, engage against the upper surface of the glass plate, and are so positioned that the assembly is slightly compressed thereby. Thus the master sheet 58 and the sensitive film 74 are pressed into close surface-to-surface contact, while the exposure is made. A number of different masters, carrying separate images eventually to be seen in superimposition, may be prepared, making use of the registration board 42. The final prints of these separate images can afterwards be combined as desired, to give the effect of superimposition, by mounting the prints on the same registration board 42, and then securing them together so that the images they carry will always be in register. The prints may be hinged together so that any combination of images may be used as a slide in a projector (see Specification 884,692). When not in use, the board 42, tray 44, and glass plates 49 can be accommodated in brackets on the outside of the box 12. Developing. The print 74 is developed in a transparent jar 96 containing ammonia gas. This is provided by a sponge 94 soaked in liquid ammonia. The print stands on this sponge, as shown, but is separated from direct contact therewith by a rubber sheet 98.