GB701465A - Apparatus for treating body surfaces, especially for the photo-mechanical productionof printing formes, and more particularly impression cylinders - Google Patents

Abstract

<PICT:0701465/III/1> Apparatus for the photo-mechanical production of printing formes, more particularly impression cylinders, by moving the surface of the printing forme over an open channel filled with a composition intended for coating the forme and which comes into contact with the surface of the forme, is characterized in that the channel has a narrow exit gap approachable to the surface to be coated, and behind the gap the channel has an enlarged cross-section over the whole length of the gap in order to ensure a uniform flow of the composition over the whole length of the gap. A cylinder 11 is rotatably and removably supported on a frame horizontally above a tie-bar 15 supported at either end by two screwed spindles 14 allowing the bar 15 to be moved toward and away from the cylinder and inclined by uneven actuation of the spindles 14. Bar 15 carries a channel 17 surrounded by a container 16 to provide a jacket space 21, through which liquid at a suitable temperature is passed to warm the channel 16; the liquid is also passed through the cylinder. The channel 16 is cleansed by warm water and filled, while the walls are still wet, by a water-soluble liquid light-sensitive composition which overflows through a narrow gap at the top removing air bubbles. The bar 15 is raised until the channel 17 lies horizontally immediately below the cylinder 11 and the surface of the composition contacts the cylinder, which is rotated slowly to be coated with a thin film of the composition. The cylinder may then be cooled by passing liquid through it, after lowering the bar 15, a reproduction copy laid on it; the cylinder may then be exposed to light while being rotated, and it may subsequently be etched by rotating in an etching basin beneath the cylinder.