Patent GB-687368-A (GB)
Title: Improvements in or relating to photographic contact-printing apparatus
IPC: G03B27/02
Filed: 1950-07-20
Abstract: 687,368. 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. 18145/50. Class 98 (ii). The apparatus comprises a cylinder or partcylindrical 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 light-sensitive material and an original sheet to be copied, means for rolling the cylindrical member to and fro between a resting position where it and the apron are apart with the apron lying tangentially to it and a working position in which the apron follows the contour of the said member, and means for holding the apron under tension in a direction perpendicular to the generating lines of the cylindrical member. As shown, an apron 4 is fixed at 15 to a table 5 and at 7 to a lamp housing 2 closed by an arcuate transparent printing support 3, and tapes 8 secured to the housing at 27 are tensioned across the support 3 and fixed to the table at 28. An original and a light-sensitive sheet are placed on the apron and by rocking the housing to the left the sheets are sandwiched between the printing support and the apron which is tensioned round the curved face of the housing. The movement of the housing is limited by a pin 18 thereon engaging in a slot in a strap 16 pivoted to the table at 17. In an alternative form, the support 3 is replaced by a transparent printing cylinder with an internal lamp and about which pass a pair of tapes secured at one end to the table and at the other to a bar attached to one end of an apron beyond the margins thereof, the other end of the apron being secured to the table, so that an original and light-sensitive sheet placed on the apron are wound on to the cylinder beneath the apron by rolling the cylinder along the table. For copying from books by reflex printing, the moving housing 2 is arranged to roll along a plate 10 which is supported above the table 5À on which the book lies, the plate having a tapered end 6 to enable it to pass beneath the page 12 to be copied close up to the spine of the book and to which tapered end one end of the apron is fastened. The other end of the apron is fastened to the housing at 7 while the tapes 8 pass from around the housing over a pulley 30 fixed to the plate and are in turn attached by springs 31 to the plate. If desired, the light-sensitive material 13 may be screened from the printing lamp except during printing, either by employing a stationary light source and providing the support 3 with a fixed screen which only when the support is in the printing position is clear of the printing light, or by disposing a reflector rotatably about the lamp within the support housing and connected by a linkage to a fixed point on the table so that movement of the housing rotates the reflector to permit illumination of the support in the printing position and to shroud the lamp from the support in the loading position towards which the housing is urged by tension springs. Specifications 650,097 and 687,369 are referred to.