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Offset Lithographic Printing Plate Maker

IP.com Disclosure Number: IPCOM000044433D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Pennington, KS: AUTHOR [+2]

Abstract

This article describes a method and apparatus for making an offset lithographic printing master in which the electrographic sheet is comprised of a flexible film substrate 1, such as a conductive film polycarbonate loaded with graphite, a thin aluminum layer film 2 on a bottom face thereof, and a hydrophobic layer 3, such as a thermal plastic, wax or ink, on the opposite face of the aluminum layer. The electrographic sheet is brought in contact with an offset plate 4, which consists of a zinc- or aluminum-coated support or the like. A stylus 5 is placed in contact with an area on the top surface of the flexible film substrate where it is desired to write. A voltage source 6 is connected between the stylus and a broad base electrode 7 contacting the surface of the flexible film substrate.

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Offset Lithographic Printing Plate Maker

This article describes a method and apparatus for making an offset lithographic printing master in which the electrographic sheet is comprised of a flexible film substrate 1, such as a conductive film polycarbonate loaded with graphite, a thin aluminum layer film 2 on a bottom face thereof, and a hydrophobic layer 3, such as a thermal plastic, wax or ink, on the opposite face of the aluminum layer. The electrographic sheet is brought in contact with an offset plate 4, which consists of a zinc- or aluminum-coated support or the like. A stylus 5 is placed in contact with an area on the top surface of the flexible film substrate where it is desired to write. A voltage source 6 is connected between the stylus and a broad base electrode 7 contacting the surface of the flexible film substrate. In response to voltage applied to the stylus, intense local heating takes place in the flexible film substrate, and the portion of the hydrophobic layer thereunder is transferred to the offset plate to form a master. The stylus may be controlled by a computer for effecting complex pattern generation.

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