Lithographic printing press for processless plate

Abstract

An imaged plate with an oleophilic resin coating non-ionically adhered on a hydrophilic substrate can be directly processed on-press by the application of disruptive mechanical tension forces to remove the unimaged areas as undissolved particles, using the tack of the ink on-press.

Description

RELATED APPLICATIONS[0001]This application is a divisional of U.S. application Ser. No. 12 / 586,764 filed Sep. 28, 2009 for “Non-Chemical Development of Printing Plates”, which is a continuation-in-part of U.S. application Ser. No. 11 / 493,183 filed Jul. 26, 2006 for “Imagable Printing Plate for On-Press Development”, which claims priority under 35 U.S.C. §119(e) from U.S. Provisional Application No. 60 / 704,140 filed Jul. 29, 2005, for “Imagable Printing Plate for On-Press Development”, and benefit under 35 U.S.C. §120 is also claimed from U.S. application Ser. No. 11 / 821,721 filed Jun. 25, 2007 for “Water Spray Development of Planographic Plates” and U.S. application Ser. No. 12 / 215,124 filed Jun. 25, 2008 for “Heated Water Spray Processor”. The complete disclosures of these applications are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]The present invention relates to imagable lithographic plates for printing.[0003]Plates of interest have a solvent-soluble, radia...

AI Technical Summary

Benefits of technology

The present invention relates to a method for producing a planographic lithographic printing plate using a radiation-sensitive coating on a hydrophilic substrate. The coating is applied by laying down a film of radiation-sensitive organic coating on the substrate and then imaging it with actinic UV, violet, or IR radiation to highly polymerize the image areas and non-image areas. The non-image areas are then removed by mechanically disturbing the coating with high-pressure water spray or brushes. The invention has the advantage of not requiring a separate developing equipment or step between the imager and the press, and there is little or no chemical treatment required of the waste stream associated with developing the plate. The method also allows for the use of higher molecular weight resins in the coating, resulting in more durable oleophilic areas and longer plate life on press.

Problems solved by technology

During start-up, when the blanket compresses against the inked-imaged plate surfaces, the high-tack adhesion of the ink to the blanket exceed the adhesion of the unimaged areas of the plate, and the cohesion of the unimaged areas of the plate also exceed the adhesion to the plate, so the fractured non-image particles are deposited on the paper web by the blanket and eventually end up in the initial start-up paper waste.

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