Lithographic Printing Plate Precursor Edge Stain Prevention
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Solution Overview
Problem
Lithographic printing plate precursors face issues with edge stains during printing on larger paper sizes, leading to commercial value loss, and existing methods for preventing stains result in setter or vendor contamination due to processing liquid residue.
Innovation Solution
A lithographic printing plate precursor with a hydrophilic agent applied to the end portions of a quadrilateral-shaped hydrophilic aluminum support, where the agent is distributed within 1 cm of the edges, preventing ink adhesion and avoiding rear surface attachment, featuring a layer arrangement with the hydrophilic agent between or on specific layers, including a phosphoric acid compound, surfactant, or water-soluble resin, and an infrared absorber like cyanine dye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the end portion is processed using a desensitizing liquid containing hydrophilic organic polymer compounds, then edge stains are prevented, but the processing liquid wraps around the rear surface causing setter contaminations or vendor contaminations
Solution Approach 1:
The patent applies the desensitizing liquid only to specific regions within 1 cm from the end portions of the support, rather than processing the entire end portion. This localized application prevents the liquid from wrapping around to the rear surface while still preventing edge stains in the critical printing areas.
Solution Approach 2:
The support is divided into different treatment zones: regions within 1 cm from end portions receive the desensitizing liquid treatment, while other areas remain untreated. This segmentation allows selective application of the processing liquid to prevent contamination spread.
2Object-affected harmful factors
If the end portion is processed after the support is cut, then edge stains are prevented, but the processing liquid wraps around the rear surface causing contamination
Solution Approach 1:
The desensitizing liquid is applied to the support before the support is cut into final size. This preliminary treatment ensures that when the support is later cut and used, the end portions are already protected against edge stains, eliminating the need for post-cutting processing.
Solution Approach 2:
The desensitizing liquid is applied only to specific regions within 1 cm from the end portions of the support, rather than processing the entire end portion. This localized application prevents the liquid from wrapping around to the rear surface while still preventing edge stains in the critical printing areas.
3Productivity
If a lithographic printing plate precursor is used for printing on paper larger than the plate, then printing is performed, but ink on the end portion creates linear stains impairing commercial value
Solution Approach 1:
The desensitizing liquid is applied only to specific regions within 1 cm from the end portions of the support, creating a localized hydrophilic zone that prevents ink adhesion at the edges while leaving the main printing surface unchanged for normal ink reception.
Solution Approach 2:
The desensitizing liquid is applied in advance to the end portions of the support to create a hydrophilic barrier that prevents ink from adhering to the edge portions during the printing process, thereby preventing linear stains before they can form.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents edge stains during printing on larger paper sizes without contaminating setters or vendors, ensuring simple manufacturing and maintaining printing quality while reducing waste.
Implementation Method 1
a hydrophilic agent is distributed on each region within 1 cm from end portions of two sides, which face each other, of the support
Implementation Method 2
the image recording layer comprises an infrared absorber and the infrared absorber comprises a cyanine dye
Data Source
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AI summary
An object of the present invention is to provide a lithographic printing plate precursor which can be manufactured by a simplified method while maintaining the performance of preventing edge stains and in which there are neither setter contaminations nor vendor contaminations. The manufacturing method for a lithographic printing plate precursor of the present invention includes: an image recording layer forming step of forming an image recording layer as an a step; a coating step of coating a partial region of the image recording layer, which is formed in the a step, with a coating liquid containing a hydrophilic agent, as a b step; and a cutting step of cutting the lithographic printing plate precursor such that the region coated with the above-described coating liquid is in a range within 1 cm from the end portion of the lithographic printing plate precursor after being cut, as a c step, in which the c step is performed after performing either the a step and b step in this order or the b step and the a step in this order, on a hydrophilic aluminum support.