Negative-Tone Plate Laminate for Durable Printing and Smooth Feeding
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Solution Overview
Problem
Lithographic printing plate precursors face issues with reduced printing durability over time and difficulty in smooth feeding from stacked laminates due to infrared absorber decomposition and inappropriate outermost layer surface roughness.
Innovation Solution
The laminate is composed of negative tone lithographic printing plate precursors with an infrared absorber having a HOMO of -5.47 eV or less and outermost layer surfaces with an arithmetic mean height of 0.3 µm to 20 µm, utilizing a hydrophilic support with an anodized aluminum surface featuring controlled micropores to inhibit absorber decomposition and facilitate smooth feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithographic printing plate precursors are stored for long time, then printing durability deteriorates due to infrared absorber decomposition, but using conventional infrared absorbers with higher HOMO levels leads to faster decomposition
Solution Approach 1:
The patent changes the energy level parameter of the infrared absorber by selecting compounds with HOMO of -5.47 eV or less (such as cyanine dyes, squarylium dyes, or pyrylium salts), which fundamentally alters the decomposition behavior and extends storage stability while maintaining printing durability
Solution Approach 2:
The patent creates a composite system combining the infrared absorber with a specific polymerizable compound (having carboxyl or sulfonic acid groups) and polymerization initiator, where the polymerization process forms a crosslinked network that stabilizes the infrared absorber and prevents decomposition during storage
2Productivity
If lithographic printing plate precursors are stacked in laminates for storage and transport, then handling efficiency improves, but feeding difficulty increases due to vacuum adhesion between stacked plates
Solution Approach 1:
The patent introduces a porous polymeric layer with specific pore structure on the outermost surface of the laminate, which allows vacuum permeation and reduces vacuum adhesion between stacked plates, enabling smooth feeding while maintaining stacking capability for efficient handling
Solution Approach 2:
The patent applies different surface properties to different regions: the polymeric layer containing infrared absorber provides local infrared absorption functionality, while the porous polymeric layer on the outermost surface provides local vacuum release functionality, with each region optimized for its specific purpose
3Ease of operation
If outermost layer surface is made smoother for better feeding, then vacuum adhesion reduces and feeding improves, but surface roughness becomes too low affecting printing quality
Solution Approach 1:
The patent creates a porous polymeric layer with controlled pore size and distribution that provides optimal surface roughness (arithmetic mean height Sa of 0.3 µm to 20 µm) - smooth enough for vacuum release and feeding, but with sufficient micro-irregularities to maintain printing quality and ink reception
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 enhances printing durability and enables smooth feeding of lithographic printing plate precursors by preventing absorber degradation and reducing vacuum adhesion, minimizing scratches and improving handling in setters.
Implementation Method 1
the image-recording layer contains a polymerization initiator, an infrared absorber, a polymerizable compound, and an acid color developing agent, and the infrared absorber contains a specific compound
Implementation Method 2
utilizing a hydrophilic support with an anodized aluminum surface featuring controlled micropores
Implementation Method 3
a hydrophilic support with an anodized aluminum surface featuring controlled micropores to inhibit absorber decomposition and facilitate smooth feeding
Implementation Method 4
the image-recording layer contains a polymerization initiator, an infrared absorber, a polymerizable compound
Data Source
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AI summary
The present invention provides a laminate of negative tone lithographic printing plate precursors each having at least one layer containing an infrared absorber with a HOMO of -5.43 eV or less on a hydrophilic support, in which in each of the negative tone lithographic printing plate precursors, at least one of an outermost layer surface on a side of the at least one layer containing an infrared absorber with reference to the support or an outermost layer surface on a side opposite to the side of the at least one layer containing an infrared absorber has an arithmetic mean height Sa of 0.3 µm or more and 20 µm or less. The present invention also provides a method of preparing a negative tone lithographic printing plate.