GB280281A - Improvements in or relating to press-frames for duplicating or printing apparatus - Google Patents

Abstract

280,281. Harris. R., and Pictorial machinery, Ltd. Aug. 11, 1926. Printing-surfaces.-A press frame for duplicating or printing apparatus, particularly photographic step-and-repeat contact apparatus, comprises a negative or unit holder adjustably carried on a supporting member which is itself so mounted on a base member as always to occupy the same position thereon and to be readily slid on and off so that when replaced whilst carrying the negative it takes up automatically its desired setting. The frame as shown in Figs. 1 and 2 is constituted by a negative holder 10, a support 11, and base 12, the base being usually uppermost and adapted to transmit pressure to a negative 13 carried on a sheet of glass 114. The holder 10' is provided with four symmetrically disposed T- section slots 14 parallel with its ends in which work the heads of corresponding bolts 16 each having a clamp 17, 18 for engaging the holder and an inwardly directed lip 15 on the support 11. The negative can be adjusted in any position by sliding the bolts in the slots and when set according to registering marks can be secured by the nuts 19. To position the support accurately on the base 12 each end of the support is provided with a tongue 20, Fig. 3, that co-operates with a corresponding groove 21 in the base 12, and centre line grooves 22, 23, Fig. 1, on these members engage tongues 24, 25. The grooves 22, 23 may be formed in one and the same member; as shown however the groove 22 is on the support 11, Fig. 4, and the groove 23 on the base 12. The support is held in set position on the base 12 by a clamping device 30, and stops 26, 27 are providedto limit the forward sliding movement of the support.