GB1015609A - Photoprinting apparatus for contact-printing sheet originals - Google Patents

Abstract

1,015,609. Photocopying apparatus. CHEMISCHE FABRIEK L. VAN DER GRINTEN N. V. March 26, 1964 [April 10, 1963], No. 12780/64. Heading G2A. Contact-printing apparatus comprises means for separating the original and copy sheets after exposure and conveying them along different paths, and also includes a member mounted in the path taken by the original which is responsive to the presence or absence of an original in said path to control blocking means in the other path to unblock or block that path accordingly. In the form shown, the superimposed original and copy sheets are carried together, by means of a porous belt 4, round an exposure cylinder 1 within which is a light source 2. After exposure, the sheets pass between a suction bbx 8 and a blowing box 9. The air in box 9 blows through a slit in its wall to impinge against a screen 10. This screen forms a narrow aperture at either end with the box 9, thus forming nozzles for jets of air, as shown by the arrows. One of these jets blows the sheets free of the cylinder 1 as they approach it. The upper sheet (copy sheet) is retained against belt 4 by suction from box 8 and is conveyed round roller 5 to pass between guides 11 and 12 to the developing section. The lower sheet (original) is detached from the upper sheet by the suction action of the other jet under screen 10 directed downwards against the wall of box 9. It is gripped by rollers 13, 14, which convey it to a delivery table 15. A plate 18, connected through a lever 19 to the core of an electromagnet 20, lies adjacent the path of the copy sheet, and can be pivoted either into the path of this sheet, so blocking its passage, or out of its path. As the original moves between rollers 13, 14, its leading edge trips the lever of a switch 16, so energizing the electromagnet and pivoting plate 18 out of the path of the copy sheet, and allowing the latter to proceed towards the developing section. If no original is passing between rollers 13, 14 (e.g. if it has remained adhering to the copy sheet and not been separated therefrom) the electromagnet is not energized. Thus the plate 18 remains in its blocking position, and prevents the sheets from being carried round roller 5 to the developing section.