Crosfield Electronics Limited

Phillip R Kellner

Alan R Gamson

Nicolette Gamson

Anthony W Rigg

Elzbeita Chudy

Mohammed A Sahi

Method of making a planographic printing member with aluminium silicate

A print member has a print surface of an epoxy novolac resin. It is particularly suitable for use as an intaglio print member that is to be laser engraved. It is best made by powder coating a powdered epoxy novolac composition onto the substrate fusing and curing it, polishing it to give non-print characteristics and then further curing it, either before or after engraving.

Printing members

The positive correction of a gravure printing surface is conducted by depositing into the cells of the surface a heat activatable composition that is inert at the temperature of deposition but which, upon heating the surface, causes etching of the cells. When the desired correction has been achieved the etching is terminated, for instance by washing. The compositions are preferably in the form of pastes and include novel compositions comprising alkali metal bisulphate.

Correction of gravure printing members

A print surface is formed by photoexposure of a photocurable resin layer through a photomask comprising an image-wise distribution of opaque material on its image surface, and sticking of the image surface to the resin layer during photoexposure is prevented by providing over the image surface a clear thin film of a natural gum or other material that is impermeable to softeners such as alcohols that are liberated from the resin layer. A coated photomask may be made by image-wise laser scanning of a transparent sheet to which opaque material such as graphite is bonded by a binder such as an alkyl cellulose, followed by application of the film over the resultant image-wise distribution of opaque material.

Formation of print surfaces

A printing member has a print surface formed of a blend of urethane and acetal polymers and is particularly suitable when it is to be engraved by laser engraving to form an intaglio print surface.

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London, United Kingdom

Phillip R Kellner