Flexographic Printing Form Microcell Patterns Ink Transfer
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Solution Overview
Problem
Flexographic printing forms using digital workflows often experience a dot-sharpening effect that reduces the size of microcell patterns, leading to inadequate ink transfer and print defects, particularly in solid areas, due to the presence of atmospheric oxygen during exposure, which results in reduced ink density and quality issues.
Innovation Solution
The introduction of microcell patterns with specific features and dimensions on the raised-image surface of flexographic printing forms, designed to work with high anilox volume ink delivery systems, which enhance ink transfer and density by creating a surface structure that improves ink laydown and uniformity, specifically patterns A, B, C, D, and E as shown in FIGS. 1-5, allowing for improved printing of solid areas and detailed features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital workflow is used for flexographic printing, then ease of operation and productivity are improved, but the dot-sharpening effect reduces manufacturing precision of microcell patterns
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the dot-sharpening effect through modified exposure parameters and oxygen barrier implementation. The in-situ mask is designed with adjusted dimensions and the exposure process uses controlled oxygen levels to counteract the anticipated pattern reduction, ensuring final pattern accuracy despite digital workflow inherent effects.
2Ease of manufacture
If atmospheric oxygen is present during exposure, then ease of manufacture is improved, but ink transfer quality deteriorates due to reduced ink density
Solution Approach 1:
The patent implements an inert atmosphere approach by introducing an oxygen barrier layer between the photopolymerizable composition and atmospheric oxygen during exposure. This oxygen barrier creates a localized inert environment that prevents oxygen inhibition of polymerization, ensuring complete curing and optimal ink transfer properties while maintaining overall process simplicity.
3Manufacturing precision
If microcell patterns are reduced in size due to dot-sharpening, then relief structure definition is improved, but ink transfer area is reduced leading to print defects
Solution Approach 1:
The patent applies parameter changes by adjusting the photopolymerizable composition formulation, exposure irradiance, and exposure time parameters to compensate for dot-sharpening effects. These parameter modifications ensure that microcell patterns maintain adequate surface area for proper ink transfer while preserving the sharpness and definition of the relief structure.
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 microcell patterns significantly enhance ink density and uniformity, as evidenced by increased opacity and reduced visual spatial non-uniformities like graininess and mottle, especially at higher anilox volumes, resulting in smoother and more solid printed ink films with improved print quality.
Implementation Method 1
Photopolymerizable elements are characterized by their ability to crosslink or cure upon exposure to actinic radiation. The actinic radiation enters the photosensitive element through the clear areas and is blocked from entering the black or opaque areas of the transparency or in-situ mask. The areas of the photopolymerizable layer that were exposed to the actinic radiation crosslink and harden
Data Source
AI summary
The present invention relates to a printing form for flexographic printing. The printing form contains microcell patterns on its relief printing surface. The presence of these microcell patterns allows for printing with a higher anilox roll volume. Also disclosed are five specific microcell patterns.