Patent GB-595749-A (GB)
Title: Improvements in and relating to processes and apparatus for the reproduction of documents
IPC: G03B27/06
Filed: 1944-04-28
Abstract: 595,749. Photographic copying apparatus. BLOCK & ANDERSON, Ltd., SHAND, S. G., and BLOCK, A. E. April 28, 1944, No. 8044. [Class 98 (ii)] Composite documentary copies of information are produced by the successive exposure of photo-sensitive stock to appropriate masters and masks at a plurality of printing stations, the stock being attached to conveyer means Which is arrested in appropriate registration and the masters and masks being carried by adjustable supporting means which permit ready variation of the composition of the information on the printed copies. Two printing stations G, H are provided for printing on sensitive material which is cut by the webfeeding mechanism D and engaged by clips on the conveyer 37 and fed in a direction parallel to the guillotined edge. The lights in the lightheads J and the driving motor are controlled from switches on the casing which are linked electrically. The adjustable masks and the printing masters at the printing stations are controlled by knobs m, q, and the handle j and observed for position through windows s, h. After exposure, the sensitive material passes through the developing unit K and is delivered at the shoot r. As shown in Figs. 4, 5, the motor 1 drives the conveyer 37 through a clutch 5 in which planetary gear is effectively driven when the sun-wheels are prevented from rotating by a sprag 8 controlled from the pedal t, but released by a toggle 10 actuated by a trip member 48 which is controlled by the passage of the sensitive material at the printing stations. Clamps each comprising a rigid bed 56 with a thick cushion layer 57 convex towards the transparent plate 60 of the printing plate are moved away from the clamping position by a toggle 61 coupled to the treadle t. It is released for clamping when the trip member 48 is actuated, breaking the toggle and allowing the springs 55 to move the plates into engagement with the master, the masks, the sensitive material and the transparent plate 60 for printing purposes. The master is secured on two spools 64 connected by a chain 65 for simultaneous rotation, one spool being rotated by the knob j. A semi-flexible opaque sheet comprises an adjustable mask which is driven by a rack and pinion controlled by the knob l. A fixed mask may also be positioned in the guides. Flexible metal tapes carry a smaller master at the printing station H which is similarly masked. The paper grips on the conveyer belt (Fig. 11) comprise a bar 13 with a portion 40 extending at right angles connected by a spring 45 to a bar 50. The whole is located in a recess in the conveyer and in the receiving position, a rod 44 carrying a roller at its end engages the arm 40 so that the bar 13 can receive the sensitive sheets. The rod 44 is controlled from the treadle t. Perforations in the sheet are retained by projections 46 on the bar 13. Similar rods 44 are provided at the rear drum 38 to release the sensitive sheet for delivery to the developer unit. An alternative paper grip comprises a forwardly inclined pin which pass through perforations in the edge of the sensitive sheet. The exposed sheet passes down a shoot 52 to the developing roller 83 dipping in a bath 85. The printing stock may comprise a continuous web, a guillotine being provided at a point beyond the developing apparatus, the separate sheets being delivered to the shoots.