Flexographic Printing Plate Roughened Edges Dot Gain Control
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Solution Overview
Problem
Flexographic printing faces challenges with dot gain due to the compression of relief patterns, leading to unreliable print quality, as existing methods lack accurate control over pressure variations and result in arbitrary adjustments.
Innovation Solution
A method for producing a printing plate with a photopolymer and carbon layer, where the carbon layer is patterned with roughened edges to enhance irradiation coverage, resulting in shallower, longer shoulders that are more sensitive to pressure changes, and a process for detecting dot gain using cameras and image processing to adjust the printing process accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a relief pattern is used for flexographic printing, then the printing process can be fast and suitable for automated packaging systems, but the compression of the relief pattern causes dot gain leading to unreliable print quality
Solution Approach 1:
The patent applies local quality by creating zones with different shoulder characteristics within the relief pattern. Specifically, it uses a combination of steep shoulders (for minimal dot gain) and shallow shoulders (for pressure sensitivity) in different areas of the printing plate, allowing each zone to serve its specific function while maintaining overall print quality and speed
2Manufacturing precision
If the relief pattern has steep shoulders to minimize dot gain, then print quality is improved, but the pattern becomes less sensitive to pressure variations making it difficult to control
Solution Approach 1:
The patent implements feedback by using shallow shoulder zones as indicators that provide visual or measurable feedback about pressure conditions. These zones show dot gain at lower pressure levels, giving operators feedback about the current pressure state and allowing them to adjust settings to achieve optimal printing conditions
3Ease of operation
If the relief pattern has shallow shoulders to increase sensitivity to pressure changes, then pressure control is improved, but excessive dot gain occurs leading to poor print quality
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatial differentiation of shoulder characteristics. Shallow shoulders are placed in specific locations where pressure sensitivity is needed for control feedback, while steep shoulders are used in areas where minimal dot gain is critical for final print quality, thus combining both benefits locally
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
This approach provides improved print quality control by making dot gain more controllable and detectable, ensuring a balanced and clear printed pattern by minimizing excessive dot gain and allowing for precise pressure adjustments.
Implementation Method 1
exposing said carbon layer and underlying photopolymer layer to irradiation in order to harden said photopolymer layer in said pattern
Implementation Method 2
The at least one rough edge of said pattern causes the irradiation to reach a larger area on the photopolymer layer during the hardening process
Implementation Method 3
When pressing the relief against the material that is to be printed, the relief will be slightly compressed and the shoulders will start to touch the material to be printed
Data Source
Figure 1a~1f
Figure 2a~3b
AI summary
The invention relates to a method for producing a printing plate for flexographic printing from a raw printing plate (1), which raw printing plate (1) comprises a photopolymer layer (2) and a carbon layer (3). The method comprises the steps of creating a pattern (4) in said raw printing plate (1) by partly removing said carbon layer (3), exposing said carbon layer (3) with irradiation to harden said photopolymer layer (2) in said pattern (4), and removing said carbon layer (3) and portions of said photopolymer layer (2) not exposed to irradiation. The method is characterised in that said pattern (4) has at least one roughened edge (38). The invention also relates to a raw printing plate (1) for flexographic printing, a printing process to enable better print quality control for flexographic printing, and a printed substrate printed using such a printing process.