Kodak Polychrome Graphics, Gmbh

Kodak Polcyhrome Graphics LLC

Robert M Organ

Harjit Singh Bhambra

Barry Jolliffe

Kelvin Dickinson

Elvyn R Tolley

A method for correcting mistakes and other imperfections in printing members is disclosed. Ink accepting areas of the printing member are rendered non-ink accepting by treatment with a deletion fluid. Deletion fluids include, for example, acids, alkalis, and oxidizing formulations. A preferred deletion fluid is concentrated sulfuric acid.

Method for making corrections on planographic printing plates

A method for preparing a substrate for a planographic printing member is disclosed. A liquid that contains water; a soluble alkali metal silicate, preferably sodium silicate; and a dispersed particulate material is coated on a support, to produce a hydrophilic layer on the support. A layer of image material may be coated over the hydrophilic layer to produce a planographic printing member. In one embodiment the liquid contains a mixture of two particulate materials, preferably alumina and titanium dioxide. The substrate has a surface roughness of about 0.1 &mgr;m to 2 &mgr;m. The substrate is suitable for preparing a planographic printing member processable to a resolution of 10 &mgr;m or less and in which the dots having a roundness of less than 2 are formed.

Substrate for planographic printing

A method for forming a planographic printing member is disclosed. A hydrophilic layer is formed on a support by contacting the support with a silicate solution that contains a silicate and a particulate material. An image layer is provided over the hydrophilic layer. The hydrophilic layer is treated to ensure that the image layer is able to change color on exposure. The hydrophilic layer may be treated with an acid, with a buffer formulation, with a colloidal suspension, or with a salt. Preferably the hydrophilic layer is treated with aluminum sulphate.

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Wantage, United Kingdom

Robert M Organ