Patent GB-109482-A (GB)
IPC: G03B27/06
Abstract: 109,482. Ogden, A. G. Sept. 13, 1916. Printing-apparatus.-In a contact printing apparatus of the type in which the sensitized surface is moved relatively to the negative between successive printings so as to obtain a number of similar prints on the surface, the sensitized Surface is carried by a frame which may be raised about hinges and also perpendicularly to the negative, and means are provided for quickly and accurately shifting the sensitized surface to the various printing positions. Fig. 2 shows a front elevation, and Fig. 4 a sectional side elevation of the apparatus. The apparatus comprises a table 1 having a central circular opening 3 over a printing lamp 68<a>, and either of two negative holders 5 may be moved along run-ways 4 into position over the opening 3. Each of the negative holders comprises a. circular plate 6 rotatable in a hole in the plate 5, and carrying a glass plate 7 above a rectangular.aperture 8. The negative 9 is placed on the glass plate and held by slidable clamps 10. The sensitized plate 36 is mounted in a frame 29 which is mounted on cams on shafts 28, Fig. 2, carried by the upper frame 14 of two cross-travelling frames 14, 13. The shafts 28 are connected by a link 31 extending between a crank 32 and a handle 30, and, when the handle is turned, in the direction of the arrow, the cams lift the sensitized plate vertically off the negative. The cams on the shaft 28 shown on the right of Fig. 2 form hinges about which the frame 29 may be lifted by means of cords 65 extending over pulleys 66 to drums on a shaft turned by a hand-wheel 62. The upper crosstravelling frame 14 has V -shaped recesses at each end which engage V-shaped guides 13y on the lower frame and is moved by means of pinions 14 engaging racks 21 on the lower frame, the pinions being operated by a worm-wheel 22 and a worm on a shaft turned by a handle 25. The position of the frame 14 on the frame 13 is indicated by . means of a pointer travelling over a scale and by the position of the handle 25 on a dial 26. The frame 13 also has V-shaped guide members 13<x> engaging recesses in rails 12 on the table 1 and is moved by pinions which engage racks 15 and are operated by a worm-wheel 16, worm 17, and handle 19, the direction of its movements being at right-angles to that of the frame 14, and its position being indicated by a pointer 72 on a scale 71 and by the position of the handle 19 on a dial 20. The sensitized plate is pressed on to the negative during printing by a pressure head 59 having a resilient covering 61 and adjustable by a screw 58 in a plunger 56. The plunger 56 may be raised or lowered by a cam 53 operated through cranks 49, 51, and a link 50, by a handle 57, the handle being secured to a shaft 48 carried by a cross-head 45. The cross-head is hinged by a pin 46 to an upright 44 and is also secured by a removable pin 47 to a second upright. When the sensitized plate is a metal one, one edge of it is clamped between an horizontal flange on the frame 29 and a bar, or between two bars, one of which, 34, has holes which are placed over pins 33 on the frame 29, and the opposite edge is clamped between two bars 38, 39, the bar 38 having brackets 40 carrying screws 41 passing through the frame 29. By tightening nuts 43 on the screws 41, the plate 36 may be stretched. When the sensitized plate is a glass one, it is carried by wedges in an aperture in a frame which is secured to the frame 29. When using the apparatus, the pin 47 is removed, the crosshead 45 is raised by a chain 76, the sensitized plate is secured to the frame 29, a negative is placed in a holder 5, and the holder is slid over the opening 3. The cross-head is then lowered, the pressure head is adjusted by the screw 58 and forced on to the plate bv operating the handle 57, and the lamp 68a is lighted to make a. print. After printing, the pressure head is raised by the handle 57, the sensitized plate is lifted by operating the handle 30, and adjusted in position for the next print by operating the handles 25, 29. The sensitized plate and pressure head are again lowered and another print made. The surface of the plate may be inspected by lifting the cross-head by the chain 76 and turning the hand-wheel 62 to raise the frame 29.