Patent GB-687369-A (GB)
Title: Improvements in or relating to apparatus for photographic contact-printing
IPC: G03B27/02
Filed: 1950-07-20
Abstract: 687,369. Photographic contact printing apparatus. GRINTEN, L. P. F. VAN DER, GRINTEN, P. A. W. VAN DER, and GRINTEN, K. J. J. VAN DER, [trading as CHEMISCHE FABRIEK L. VAN DER GRINTEN]. July 20, 1950 [July 21, 1949], No. 18146/50. Class 98 (ii). The apparatus comprises a cylindrical or part-cylindrical member of light-transmitting material adapted to be illuminated from its concave side, a flexible apron adapted to be laid close to the convex side and to follow the contour of the cylindrical member and sandwich between itself and said member a sheet of lightsensitive material and an original to be copied, means for effecting relative motion between the apron and said member to and fro between a rest position, in which the apron extends in a plane tangential to said member and terminates in a thin, flat edge parallel to the generators of said member, and a working position in which the apron lies close to the member with the terminal edge against it, and means engaging the apron for holding it under tension in a direction perpendicular to the generators of the cylindrical member without obstructing the terminal edge of the apron. As shown, an apron 3 has two pairs of tapes 5, 7 attached to bars 4, 6 carried by the apron beyond the margins thereof, tapes 7 being looped about a transparent stationary contact printing cylinder 2 having a central lamp 1, the two pairs of tapes passing about pulleys 8, 9 and being connected by springs 10. A book to be copied is supported on a carriage 13 running on rails 15 and the book and carriage lie between the tapes 5 so that the page 11 to be copied and the light-sensitive sheet 12 may be placed over the apron which ends in a flat plate with a thin edge 4 adapted to pass close up to the spine of the book. On moving the carriage to the right, the page of the book and the light-sensitive sheet are sandwiched between the cylinder and the apron and a reflex contact print is made. Alternatively, the tapes 5 may be dispensed with and the apron 3 may be secured at 4 to the tapered edge of a plate 22, the tapes 7 passing over pulleys 24 carried by the plate to which the tapes are attached by springs 10, the book being supported so that the page to be copied overlies the apron and the book and plate being mounted so as to be displaceable beneath the cylinder 2. In a further embodiment, the apron passes from the edge of the plate partially round the cylinder from which it is led over external tensioning rollers to a pulley 24 and the cylinder is recessed to accommodate the bulge near the spine of the book formed by the part of the book not containing the page to be copied. A modification shown in Fig. 3 employs only an arcuate support 2 against which is moved a book which is carried in a hinged holder 13 with the page to be copied overlying an apron 3 which is tensioned by springs 10 connected beyond the margins of the apron to its terminal edge 4. A further embodiment employs a stationary plate with an upwardly sloping tapered end to which is secured without sag one end of a fixed apron, so that by moving an arcuate support downwardly against it the apron is tensioned. In another embodiment the apparatus is identical with that shown in Fig. 3 of Specification 687,368. Specification 650,097 also is referred to.