Automated Engraving of Gravure Cylinders

Abstract

A computer-based system for automated engraving of gravure cylinders has been developed and is now used in a normal production environment. Either fully composed pages or individual page components are scanned and stored on a large disk. In the case of fully composed pages, an operator uses a TV display to segment the page image into line and tone areas. The image is then coded by a software process and is ready for subsequent engraving. Prior to the scanning of page components, the operator uses a tablet in order to demark both cropping locations and to specify the location of the components on the final page image. The scanned components are then assembled and coded by a single software process. The encoding process reduces the data storage requirement by a factor of two without any apparent loss of quality. Data are retrieved from disk storage, buffered, decoded, transmitted to a special formatter, and used to drive a Helio Klischograph,® which engraves the cylinder in approximately one hour. Completely arbitrary imposition (the arrangement of pages on the gravure cylinder) is accomplished at the time of engraving. Provision is made for the arbitrary intermixture of computer-processed pages and conventional engraving by means of Cronapaquesgi mounted on the companion scanning machine. The motivation for this development was to reduce the cost and time required for the production of gravure cylinders.