GB1311194A - Copying machine and method - Google Patents

Abstract

1311194 Photographic copying machines MINNESOTA MINING & MFG CO 8 April 1970 [9 April 1969] 16754/70 Heading G2A In a copying machine an intermediate sheet and an original are exposed to a light source in contact, then the intermediate is placed in contact with a copy sheet and the two heated, after which the copy sheet is stripped away from the intermediate and heated again to complete the development. As shown, the photo-sensitive intermediate sheet 29 winds off a supply drum 28, is guided round a print drum 30, and is taken up on a drum 35. An original is introduced on chute 14 and passes round drum 30 in contact with intermediate 29 and an exposure made by a light source 31. The drum 30 is perforated, and a positive pressure is applied to its interior. A stripper bar 39 bears against the drum, and after exposure it removes the original and guides it into a recovery chute 17. A copy sheet from a supply tray 50 is fed into the system by a roller 51, and is held in contact against the intermediate 29 by a belt 42. A heated platen 33 is brought into contact with the intermediate, so that an image transfer takes place as the sheets pass the platen. A stripper bar 54 then separates the copy sheet from the intermediate, the copy sheet being carried by the belt 42 round a drum 45 which applies further heat to complete the development of the image. The copy sheet is then finally delivered into a chute 21. As the copy sheet is stripped away from the intermediate by bar 54, the platen 33 is retracted and the direction of travel of the intermediate reversed so as to prepare it for a subsequent exposure. The various operations are controlled automatically by a system of micro-switches. If multiple copies of a single original are required, the stripper bar 39 does not bear against the print drum 30, and this has a negative pressure induced within it, so that the original is retained and is carried round on drum 30 for repeated exposures, the sequence reverting to that described above for final copy. The number of copies required can be set by a count switch (25), Fig.1 (not shown).