Patent GB-500432-A (GB)
Title: Improvements in or relating to apparatus for photographic composition on printing cylinders having sensitized surfaces
IPC: G03F7/24
Filed: 1937-08-09
Abstract: 500,432. Photographic contact-printing apparatus. HUEBNER, W. C. Aug. 9. 1937. No. 21856. [Class 98 (ii)] An apparatus for photographic composition on printing cylinders having sensitized surfaces comprises the cylinder rotatably supported in a framework, a negative holder which is conformable under pressure to the surface of the cylinder and having an air sealing gasket enclosing the working area thereof and an airexhausting opening, and a carriage for the holder mounted in said framework to move parallel to the axis of the cylinder. In the form shown, the axle portions 57 of the sensitized cylinder 58 rest on pairs of rollers 60 carried in members 59 at either end of the machine. These members are simultaneously vertically adjustable by screws 48 operated by skew gearing from the shaft 53 with handle 56. The cylinder is held in place from above by pairs of rollers 64 adjustably mounted on rods 61. Longitudinal movement is prevented by centring points 72 threated in blocks 69 and screwed into centre-bores in the cylinder- The length of the machine is adjustable to receive cylinders of different lengths. The end plate 32 moves on the base on rollers 44 and may be clamped by screws 42. It is moved by the handle 38. This turns the shaft 36 and. by a chain 40 on sprockets 39, the shaft 37. These shafts carry pinions engaging racks on the undersides of the rods 33. Clamping screws 41 engage the rods 33. The carriage 109 sliding on the bar 389 carries the negative and printing lamp holders. To position the carriage longitudinally a screw clamp 112 may engage one of the teeth 101 of a rack attached to a bar 97. slidable relative to the bar 389, for fine adjustment, by the micrometer device 106. The individual teeth 101 of the rack may be adjusted by set-screws 104, Fig. 15, acting on wedges 102, 103. The negative holder, Fig. 17, comprises a flexible transparent sheet 127 to the underside of which the negative 134 is attached by adhesive tape for example. The sheet is surrounded by an air sealing gasket 128 and is kept in contact with the cylinder by atmospheric pressure, air being exhausted by a pump 139 from the nozzle 135. The negative holder is attached by screws 129, 130 to an adaptor bar secured by screws 132 to the flange 116 of the subcarriage 114 of the carriage 109. The subcarriage 114. is adjustable by the screw 113 to accommodate cylinders of different diameters. It also carries the hood 115 containing the printing lamps. The hood is flexible and its curvature may be varied to suit the cylinder. It may be fixed in any position by wing nuts 124. Figs. 8 and 10 show the arrangement for locating the negative circumferentially on the cylinder. Two bands 76 and 77 are clamped side -by-side round the cylinder, near one end, by bolts 78, 80 with nuts 79, 81. They are located relatively to one another by a spring- pressed latch 84 on the band 76 engaging one of a series of notches 82 in the band 77 which also carries a rack 85. The latter engages a rack 87 vertically adjustable by a micrometer device 91. The cylinder is positioned roughly by loosening the band 77 and engaging the latch 84 with a suitable notch 82. The fine adjustment is made by the micrometer 91. The micrometer is mounted on a carriage 89 adjustable by a screw 189 to suit different cylinder diameters.