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Positive lithographic printing plate precursor

A lithographic printing plate and precursor technology, which is applied in the field of positive lithographic printing plate precursors, can solve the problems of limited shelf life of coatings, etc.

Inactive Publication Date: 2005-04-27
AGFA NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] A particular problem associated with thermal plate precursors is the limited shelf life of the coating

Method used

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  • Positive lithographic printing plate precursor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0030] Preparation of Lithographic Support 1 (Comparative Example)

[0031] Immerse a 0.30mm thick aluminum sheet in an aqueous solution containing 40g / l sodium hydroxide at 60°C for 8 seconds to remove oil stains, and then rinse it with demineralized water for 2 seconds. Then at a temperature of 33°C, 130A / dm 2 Under the current density of 1, use alternating current to roughen the surface of the sheet electrochemically in an aqueous solution containing 12g / l of hydrochloric acid and 38g / l of aluminum sulfate (18 hydrate) to form an average center line roughness Ra of 0.5μm Surface topography. After rinsing with demineralized water for 2 seconds, the aluminum flakes were etched with an aqueous solution containing 155 g / l sulfuric acid at 70° C. for 4 seconds, and then cleaned with demineralized water at 25° C. for 2 seconds. Then at 45°C temperature and 22A / dm 2 Anodization of flakes in an aqueous solution containing 155 g / l sulfuric acid at a current density to form 2.90 g...

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Abstract

The present invention is printing plate precursor for positive planography. The printing plate precursor includes surface roughened and anode oxidized aluminum carrier with hydrophilic surface and thermosensitive lipophilic coating on the hydrophilic surface. Inside water-containing alkali developing liquid, the coating has its area exposed in heat or infrared ray with even higher dissolving rate than un-exposed area. The printing plate precursor features that the hydrophilic surface has surface roughness expressed with Ra less than 0.45 micron and contains alumina more than 3.0 g / sq m. The smooth surface results in longer storage period.

Description

technical field [0001] The present invention relates to a heat sensitive positive working lithographic printing plate precursor requiring treatment with an aqueous base. Background technique [0002] Lithographic printing presses use a so-called printing master, such as a printing plate mounted on the cylinder of the printing press. A lithographic image is carried on the surface of the master, and a print is obtained by applying ink to the image and then transferring the ink from the master to a receiver material, usually paper. In common lithographic printing, ink and an aqueous fountain solution (also known as dampening solution) are supplied to a lithographic image consisting of oleophilic (or hydrophobic, i.e., ink-accepting, water-repelling) areas and Hydrophilic (or oleophobic, that is, water-accepting, ink-repelling) regions. In so-called waterless offset printing, the lithographic image consists of ink-accepting areas and ink-non-stick (ink-repelling) areas, and in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B41N3/03
Inventor M·范丹姆J·费梅尔斯
Owner AGFA NV