Method and composition for removing residual ink image from offset printing blanket

Abstract

A thickened aqueous cleaning solution for removing residual ink images from the surface of a blanket used in offset lithographic printing which has been subjected to printing using radiation-curable ink. The cleaning solution comprises an alkaline builder, a thickener, a co-solvent, a surfactant and water. A method for removing the residual ink images from the blanket comprises removing the blanket from the offset lithographic printing press, applying a layer of the thickened aqueous cleaning solution to the blanket, rubbing the surface of the blanket, for example with rags or a scouring pad, and removing the soiled cleaning solution.

Description

technical field [0001] The present invention relates to the field of offset printing and in particular to the restoration of blankets used with radiation curable printing inks in such printing. Background technique [0002] Offset printing is a printing method well known in the industry. In this method, the image is transferred from an inked lithographic master to a rubber or elastomeric surface and then onto a substrate rather than directly to the substrate as in a letterpress printing press. The most common offset printing technique uses water and ink. [0003] The offset printing process starts with a blank unimaged lithographic precursor in the form of a printing plate coated with a radiation sensitive medium. The lithographic precursor is converted into a lithographic master by a process whereby more hydrophilic regions and more hydrophobic regions are created on the surface of the printing plate, typically by imaging. This can be done by photographic methods, or dir...

AI Technical Summary

Problems solved by technology

In the subsequent printing process, the residual image appears on the printed matter in various printed colors as a blurred ghost image of the previously printed image, thus affecting the quality of the printed product, especially for high-definition works

[0010] Frequent blanket changes add significantly to press operating costs