Lithographic printing forms
AssigneeKodak Polychrome Graphics LLC
InventorsGeoffrey Horne, Kevin Barry Ray, Alan Stanley Victor Monk, Stuart Bayes
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Abstract
The invention provides a lithographic printing for precursor having an imagable coating on an aluminum support, wherein the imagable coating comprises a polymeric substance comprising colorant groups, and wherein the aluminum support on which the coating is provided is anodized but not subsequently modified by means of a post-anodic treatment compound, and the coating does not comprise a colorant dye. The polymeric substance may also comprise pendent infra-red or developer dissolution inhibiting groups, and these groups may also be the colorant groups themselves.
Claims22
A lithographic printing form precursor having an imagable coating on a aluminum support, wherein the imagable coating comprises a polymeric substance comprising colorant groups, wherein the aluminum support on which the coating is provided is anodized but not subsequently modified by means of a post-anodic treatment compound, and wherein the coating does not comprise a free colorant dye.
15 A precursor as claimed in claim 1, wherein the composition comprises a pigment.
A precursor as claimed in claim 15, wherein the pigment is carbon black, lamp black, furnace black, channel black, iron (III) oxide, manganese oxide, Milori Blue, Paris Blue, Prussian Blue, Heliogen Green or Nigrosine Base NG1.
A method of preparing a lithographic printing form precursor having an imagable coating on an aluminum support, the method comprising the steps of:
- a) anodising an aluminum sheet (which is to serve as the support);
- and
- b) without having effected a chemical treatment step after the anodising step, applying a composition comprising a polymeric substance to the anodised surface of the aluminum sheet and drying the composition to form the imagable coating thereon, wherein the polymeric substance comprises pendent colorant groups, and wherein the composition does not contain a free colorant dye.
A method of making a printing form from a printing form precursor, the precursor comprising an imagable coating on an aluminum support, wherein the imagable coating comprises a polymeric substance comprising colorant groups, the aluminum support on which the coating is provided is anodized but not subsequently modified by means of a post-anodic treatment, and wherein the coating does not comprise a colorant dye, the method comprising the steps of:
- a) exposing the coating imagewise;
- and
- b) removing the exposed regions of the coating using a developer liquid.
21 A method as claimed in claim 18, wherein imagewise exposure of the coating is effected using electromagnetic radiation having a wavelength between 600 and 1400 nm, the coating containing means for absorbing radiation of such wavelength and producing heat.
Dependencies are inferred from the claim text.