Patent GB-1251266-A (GB)
IPC: G03B27/02
Filed: 1969-05-01
Abstract: 1,251,266. Step and repeat printers. R. H. NAMEPLATES Ltd [trading as REPRO PRECISION EQUIPMENT], Feb.5, 1970 [May 1, 1969], No.22392/69. Heading G2A. In a step and repeat contact printer an original (e.g. a negative) is supported in a carriage C which is mounted by means of runners on rails so that it can move in two mutually perpendicular directions, the runners having means for locking them to the rails in any desired position. Movement of the runners along the rails is facilitated by anti-friction bearings. As shown, a base board 1, on which the photo-receptive sheet is laid, has four posts S 1  - S 4  at its corners which support parallel rails CTR1 and CTR2. Along these slide respective pairs of runners TR1, TR2 and TR1', TR2', which between them support a further pair of parallel rails CR1 and CR2 which are perpendicular to the first pair of rails. The carriage C comprises a rectangular frame 4 which is mounted on rails CR1, CR2 by means of R1 R1 and R2, R2'. Thus the carriage C can be moved to any part of the photo-receptive sheet on the board 1. The runners R1', R2' each carry a pair of brake blocks 10, 10' Fig.4. The blocks are drawn together, so as to clamp round the rail, by springs 11, 11', and have spacers 12, 13 between them. Spacer 13 has a flattened section, and is formed at the end of a rod 14. When oriented in the position shown in Fig.4, the brake blocks are clamped to the rail. When rod 14 is turned through an angle, the movement of the flattened end 13 forces the blocks 10, 10' apart, against the springs, so that the runner is free to move along the rail. The brakes for both runners R1', R2' can be operated by raising or lowering a single centrally placed control member 20. The frame 4 carries a support 6 which holds a rigid transparent sheet 7, on whose lower surface 8 the negative is secured. Flanges 30 on support 6 have holes which fit on to pins 29 on carriage C, in order to locate the support accurately. Frame 6 can be pressed downwards by spring-loaded feet 31, so that plate 7 is brought firmly into contact with base 1 Fig. 3, (not shown). When control member 20 is operated to release the brake blocks, at the same time it operates cranked plates 23 to lift the support 6 and so move plate 7 slightly away from baseboard 1 position of Fig. 2, so as to permit free movement of the carriage. Above the carriage a lamp hood 34 is mounted. A scale beam 36 is secured to the runners TR1, TR2, and along this beam slides a cursor 37 which can be locked in any position along the beam by a levered screw. A stop member 38 can likewise slide along the rail CRT1 and be locked in any position. As shown in Fig.1 the cursor 37 is moved along scale 36 to a predetermined distance from runner TR2, this being the distance through which it is desired to index the carriage C, and locked in that position. Stop 38 is then moved along track CRT1 until it abuts against the cursor, and also locked. The carriage is now slid along tracks CTR1, CTR2 until runner TR2 comes up against the stop 38. The carriage has thus been moved through the predetermined distance. Meanwhile, cursor 37 has been moved on by the same distance, so that the indexing step can now be repeated. A similar arrangement can be used for indexing the carriage along the other pair of tracks CR1, CR2. Figs.6-9 (not shown) illustrate this indexing movement in more detail.