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US 8,807,029 B2Granted
Plateless lithographic printing
OwnerThomas E. Lewis, Nanda Nathaninventors
Life of this patent
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Abstract
Embodiments of the present invention dispense with the need for lithographic printing plates, instead facilitating direct transfer of ink from a permanent cylinder to a recording medium. Accordingly, instead of being permanently modified to exhibit oleophilic and oleophobic (or hydrophilic) regions, the cylinder is effectively “programmed” with the image prior to each transfer of ink.
Claims13
A method of printing comprising the steps of:
- a. providing a hydrophilic, ink-receptive lithographic surface having a printing area;
- b. applying ink to the printing area, the ink being adsorbed thereon;
- c. exposing the ink-bearing printing area to laser output in an imagewise fashion, a portion of the energy of the laser output (i) being transmitted without absorption through the ink and (ii) being absorbed, at least in part, by the lithographic surface, the energy absorbed by the lithographic surface temporarily fixing the adsorbed ink on the printing surface;
- d. applying a polar liquid to the printing area, the polar liquid removing ink from portions of the printing area that have not received laser exposure;
- and
- e. transferring the temporarily fixed ink to a recording medium via contact therewith.
3 more elements
Dependencies are inferred from the claim text.