Flexographic Relief Plate Imaging with Tunable UV LED Exposure
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Solution Overview
Problem
Existing UV LED systems for flexographic printing plates lack the ability to individually adjust and control power intensity and wavelength outputs, limiting the ability to optimize geometric characteristics of relief printing features such as planarity, shoulder angle, and edge sharpness, necessitating changes in photocurable layer composition for improved imaging.
Innovation Solution
Employing an arrangement of UV LED lights with adjustable power intensity and different wavelength outputs, and/or collimation, to selectively cross-link and cure photocurable layers, allowing independent control of geometric characteristics without altering the photocurable layer composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If UV LED systems are used for exposing photocurable layers, then the printing process can be automated and reproduced consistently, but the ability to individually adjust power intensity and wavelength outputs is limited, preventing optimization of geometric characteristics
Solution Approach 1:
The UV LED system is divided into multiple independently controllable LED elements arranged in arrays. Each LED or group of LEDs can be individually controlled in terms of power intensity and wavelength output, allowing separate optimization of different regions of the photocurable layer exposure. This segmentation enables the system to maintain automation while gaining the versatility to adjust geometric characteristics of relief features.
Solution Approach 2:
The system incorporates dynamically adjustable power intensity and wavelength outputs for each LED element. Rather than fixed parameters, the LED controls can be modified during operation to optimize imaging characteristics for different printing jobs. This dynamic adjustment capability resolves the contradiction by allowing automated operation with adaptable parameters.
2Manufacturing precision
If the photocurable layer composition is changed to improve imaging characteristics, then geometric characteristics like planarity and edge sharpness can be optimized, but the complexity of determining optimal composition for different jobs increases
Solution Approach 1:
Instead of changing the chemical composition of the photocurable layer, the invention optimizes imaging characteristics by changing the exposure parameters - specifically the power intensity and wavelength outputs of individual UV LED elements. This parameter change approach maintains manufacturing precision while avoiding the complexity of formulating different photocurable compositions for different jobs.
Solution Approach 2:
The system uses multiple UV LED elements with different wavelength outputs to selectively expose different regions of the photocurable layer, effectively creating a digital copy of the desired imaging characteristics through controlled radiation patterns rather than physical changes to the photocurable material composition.
3Manufacturing precision
If multiple photocurable layers with different compositions are used to achieve desired imaging characteristics, then geometric precision can be improved, but the time and cost for determining optimal compositions for each job increases
Solution Approach 1:
A single photocurable layer composition is designed to be universally applicable to multiple printing jobs by using multiple UV LED elements with different wavelength outputs and adjustable power intensities. This multi-functional exposure system eliminates the need to determine optimal compositions for each specific job, saving time while maintaining geometric precision through parameter adjustment rather than material formulation.
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 enables efficient optimization of imaging characteristics like planarity, shoulder angle, and edge sharpness of relief features, reducing costs and time in determining optimal printing settings for specific jobs.
Implementation Method 1
The photocurable layer(s) can include any of the known photopolymers, monomers, initiators, reactive or non-reactive diluents, fillers, and dyes. As used herein, the term 'photocurable' refers to a composition which undergoes polymerization, cross-linking, or any other curing or hardening reaction in response to actinic radiation
Implementation Method 2
the source of actinic radiation comprises an arrangement of UV LED lights, wherein the arrangement of UV LED lights comprises one or more sets of UV LED lights, UV LED tubes, or a combination thereof that operate at different wavelength outputs
Data Source
AI summary
A method of controlling imaging characteristics of at least one relief printing feature created in a photosensitive printing blank during a platemaking process is provided. The photosensitive printing blank has a photocurable layer disposed on a backing layer. The photocurable layer is selectively exposed to a source of actinic radiation to selectively cross link and cure portions of the photocurable layer. The source of actinic radiation comprises one or more sets of UV LED lights that operate at different wavelength outputs and/or that are collimated to achieve different angles of UV light, and a power intensity of each individual UV LED light is individually adjusted and controlled. A relief image is revealed when the exposed photocurable layer is developed comprising at least one relief printing feature exhibiting geometric characteristics that provide for optimal printing performance.