GB224657A - Improvements in photographic printing apparatus - Google Patents

Abstract

224,657. Soullier, E. J. B. W. Sept. 25,1923. Printing-apparatus. - Relates to apparatus for step-and-repeat printing of the kind comprising a main frame movable successively through adjustable distances in one direction, and a second frame, carrying the sensitive sheet, supported on the first frame, and movable successively thereupon through adjustable distances in a direction at right angles to the first, and consists mainly in pedal controlled means for producing a step-by-step movement of the second frame. The movements of the first frame are hand-controlled. The controlling pedal may also actuate the exposure-making device, and a spring- controlled pressure platen. A box 1, Fig. 2, containing the light source and a ruby lamp, is closed at the top by a glass plate supporting an apertured card 11, Fig. 3, in which the negative 8 is held by a wedge device 9. Supported on the box 1 and slidable horizontally thereupon are (1) a frame 30 carrying a, fixed stop 38, and (2) a bar 34, actuated by a weight 39 and carrying a fixed stop 35 and an adjustable stop 36. The frame 30 and bar 34 are held in any position by a handcontrolled gripping-device 41, 42. Mounted at one end of the frame 30, and at right angles to the bar 34 is a frame 44, shown in plan in Figs. 3 and 8, having parallel guideways in which slide (1) a holder 46 for the sensitive sheet, carrying a fixed stop 56, and (2) a bar 45 carrying a fixed stop 54 and an adjustable stop 59. The holder 46 and bar 45 are connected by detachable belts running over pulleys to spring drums in a housing mounted on the left of the frame 44, and are held in any position by a gripping device 70, 71. The sensitive sheet is gripped at one edge between clamping-bars 28, 29, Figs. 3 and 9, on the holder 46 and is supported by parallel elastic cords held taut by weights, and spaced apart on the top of the box 1. In operation, with the frame 30 and bar 34 as shown in Fig. 2, and with the holder 46 and bar 45 drawn, fully to the right, against a marginal stop 62, Fig. 3, the first exposure is made by depressing a pedal 21, which causes, through rods 19, the pressure platen 13 to press the sensitive sheet against the negative, and operates a switch controlling the printing-light. This switch may be time-controlled. At the same time, the pedal, through linkage connected to a Bowdeti or like cable 73, actuates the gripping- device 70, 71 and releases the bar 45, which moves to the left under the action of its spring drum until ths stop 59 engages the stop 56. The stop 59 is previously adjusted so that this movement corresponds to the width of the image. When the pedal is released, the gripping device 70, 71 holds the bar 45 and releases the holder 46, which moves to the left under the action of its spring drum until the stop 56 re-engages the stop 54. The apparatus is now ready for the second exposure, and the cycle of operations is repeated at each actuation of the pedal. When a row of images has been completed on the sheet, the gripping device 41 is hand-operated to release the frame 30 which is then pushed by hand until the stop 38 engages the stop 36, which has previously been adjusted so that this movement corresponds to the length of the image. The holder 46 and bar 45 are then drawn again fully to the right after releasing the gripping device 70, 71, and printing of the second row of images may proceed. When this row has been completed, the gripping device 42 is hand-operated to release the bar 34, which moves under the action of the weight 39 until the stop 35 re-engages the stop 38, and printing of the third row may proceed. These operations are repeated for succeeding rows. An adjustable stop 40 determines the margin of the sheet.