Digital Image Analysis for Flexographic Mask Layer Quality
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Solution Overview
Problem
Current methods for assessing the imaging quality of flexographic printing plates rely heavily on human observation, which is subjective and limited in detecting deviations in microscreen patterns, especially with the increasing complexity of multibeam imagers.
Innovation Solution
A system and method for objectively assessing imaging quality by analyzing microscreen patterns using a digital image analysis system. This involves generating a data array of inspection parameters from the digital image of the mask layer and comparing them to reference parameters to detect deviations and calculate correction factors for beam balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If human operators assess imaging quality by visual inspection or microscope observation, then the assessment process is simple and requires minimal equipment, but the measurement precision and objectivity are limited and subjective
Solution Approach 1:
The patent replaces the mechanical/visual inspection system (human operators using microscopes) with an automated digital image analysis system using computers and software algorithms. This substitution enables objective, precise measurement of microscreen patterns and mask openings, eliminating human subjectivity while maintaining operational simplicity through automated processing.
Solution Approach 2:
The patent creates digital copies (images) of the mask layer and microscreen patterns, then analyzes these copies using computer-based image processing. This allows multiple measurements and analyses of the same physical structure without physical contact or distortion, improving measurement precision while keeping the physical inspection process simple.
2Measurement precision
If digital image analysis system is implemented for objective assessment, then measurement precision and objectivity improve, but device complexity and implementation cost increase
Solution Approach 1:
The patent designs the digital image analysis system to perform multiple functions: assessing focus position, evaluating beam balancing, analyzing microscreen patterns, and measuring mask opening dimensions. This multi-functionality consolidates what would otherwise require multiple separate measurement devices, making the system more economical to implement while providing comprehensive imaging quality assessment.
Solution Approach 2:
The system uses the imager's own output (the imaged mask layer) as the test object, eliminating the need for separate test artifacts or calibration standards. The microscreen patterns are imaged directly onto the mask layer using the same imager being assessed, allowing the system to self-diagnose and evaluate its own performance.
3Productivity
If multibeam imagers with 64 or more beams are used, then productivity and imaging speed improve, but the difficulty of detecting and measuring imaging quality deviations increases
Solution Approach 1:
The patent divides the assessment of multibeam imager performance into separate measurable parameters: individual beam positions, individual beam powers, microscreen pattern fidelity, and mask opening dimensions. By segmenting the complex multibeam system assessment into these discrete components, the system can detect and measure deviations in each beam independently, making the evaluation of 64+ beams manageable and precise.
Solution Approach 2:
The patent uses microscreen patterns as an intermediary test object that translates complex multibeam interactions into observable mask opening patterns. The microscreen pattern acts as a mediator that converts individual beam parameters into a visible pattern that can be captured and analyzed, enabling indirect measurement of beam balancing and positioning accuracy without directly measuring each beam.
4Manufacturing precision
If microscreen patterns with varying dot sizes are imaged, then surface structure control for ink transfer optimization improves, but the complexity of assessing imaging quality across different patterns increases
Solution Approach 1:
The patent systematically varies parameters of the microscreen patterns (dot size, spacing, frequency) and uses the digital image analysis system to measure how these parameter changes affect the resulting mask openings and surface structures. This allows precise control and optimization of surface structures for different ink transfer requirements while the automated system handles the complexity of assessing multiple pattern variations.
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 proposed solution enables more precise and objective assessment of imaging quality, improving the printing properties of flexographic printing plates by optimizing beam balancing and surface structures, thereby enhancing ink transfer and print quality.
Implementation Method 1
corresponding portions of the mask from the polymer plate corresponding to all solid printed regions of the image are completely removed by means of a laser beam
Implementation Method 2
the laser power for each individual beam is selected in a way that the size of the mask opening just slightly overlaps with the mask openings cut by neighboring beams. The beams are switched 'on' continuously in solid rendition areas, according to the image information of the image to be printed
Implementation Method 3
the photopolymer is selectively cured by UV light that penetrates the portions of the plate where the LAMs layer was removed
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Method and system for performing quality analysis of an imaged printing plate precursor mask layer includes a detector and computer memory media programmed with machine-readable instructions. The mask layer has a plurality of openings created by a first imager corresponding to information including micro-screen information. The printing plate precursor includes a photopolymer to be cured by exposure to actinic radiation. The detector acquires a digital image of at least a sample portion of the openings formed in the mask layer corresponding to the micro-screen information for inspection. The first set of machine-readable instructions causes a processor to generate, based on the digital image, a first data array comprising a plurality of inspection parameters. The second set of machine-readable instructions causes a process to compare the plurality of inspection parameters from the first data array and a plurality of reference parameters from a second data array.