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US 4,231,659 AGranted
Method of making an overlay mask and a printing plate therefrom
AssigneeThe Gerber Scientific Instrument Company
InventorDavid J. Logan
Life of this patent
Estimating the term…
Abstract
A method of making overlay masks for photoetching of printing plates with printing matter utilizes a photoplotter having an optical exposure head to precisely expose a photosensitive film in a predetermined mask pattern. The pattern may include symbols, "knock out" windows for cropping pictures in both grey and color halftones, and line work such as framing for pictures and other printing matter.
Claims16
A method of producing a printing plate with an overlay mask comprising:
- placing a film having a photosensitive surface in an automatic precisely controlled photoplotter having an optical exposure head with the photosensitive surface of the film disposed for exposure by the head;
- controllably moving the exposure head relative to the photosensitive surface of the film with accurate, predetermined motions, and simultaneously exposing the film surface with the exposure head to precisely expose the film in accordance with the pattern of a desired printing plate overlay mask with sharply separated transparent and opaque areas in linear, rectangular or other shapes that divide a plate into prescribed areas for receiving and not receiving printed matter through the mask;
- developing the exposed film and producing the precisely exposed overlay mask with a mask pattern in contrasting transparent and opaque areas corresponding to the film exposure;
- and
- photoengraving a printing plate directly by means of the precisely exposed overlay mask for accurate disposition of printing information on the printing plate.
2 more elements
A method of making an overlay mask for photographic engraving of a printing plate comprising:
- mounting a photosensitive film in a programmable photoplotter having an exposure head for movement of the head and film relative to each other;
- programming the photoplotter with a mask program having data defining the precise dimensions and positioning of the graphic images desired in an overlay mask as applied to a printing plate;
- directing a beam of light from the exposure head of the plotter onto the photosensitive film to expose a spot on the film;
- moving the exposure head and film relative to one another in the photoplotter under program control to cause the spot of light to move over the film and expose the film in accordance with the precise dimensions and positioning defined in the mask program;
- and
- producing an overlay mask with the desired graphic images from the film exposed in the programmed photoplotter by developing the exposed film without supplemental reduction or enlargement of the image dimensions.
3 more elements
Dependencies are inferred from the claim text.