Modulated UV LED Flood Exposure for Flexographic Printing Plates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-intensity UV LED exposure in flexographic printing can cause surface contraction and 'cupping' due to excessive heat generation, leading to increased print gain and potential image degradation.
Innovation Solution
Modulating high-intensity UV LED light sources to lower intensities for flood exposure of photocurable printing blanks, using reflective mirrors to distribute light evenly and control the angle of mirrors to shape relief printing dots, while maintaining the photocurable printing blank and UV LED light source in a fixed position during exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-intensity UV LED light sources are used for flood exposure, then exposure speed and productivity are improved, but heat generation increases causing surface contraction and cupping
Solution Approach 1:
The patent applies periodic action by using intermittent or pulsed UV LED exposure instead of continuous high-intensity exposure. The system controls the UV LEDs to expose the photocurable printing blank in cycles, allowing heat to dissipate between pulses while still achieving complete curing over time. This resolves the contradiction by maintaining productivity through repeated exposure cycles while preventing excessive heat accumulation that causes surface contraction and cupping.
Solution Approach 2:
The patent applies dynamics by making the UV LED intensity adjustable and controllable during the exposure process. The system can dynamically adjust the intensity levels, exposure duration, and timing based on the specific requirements of the photocurable material and desired print quality. This dynamic control allows optimization between exposure speed and heat generation, preventing surface deformation while maintaining efficient curing.
2Productivity
If high-intensity UV LED exposure is used, then curing efficiency is improved, but surface contraction and image degradation occur
Solution Approach 1:
By using periodic or pulsed exposure cycles, the system achieves thorough curing of the photocurable material while allowing the substrate to return to ambient temperature between pulses. This prevents thermal deformation and surface contraction that would otherwise cause image degradation, thereby maintaining both curing efficiency and image integrity.
Solution Approach 2:
The patent applies parameter changes by adjusting multiple exposure parameters including intensity, duration, wavelength, and pulse frequency to optimize the curing process. By carefully controlling these parameters, the system achieves complete curing without excessive heat input that would cause surface contraction and image degradation, thus resolving the contradiction between curing efficiency and image integrity.
3Loss of time
If UV LED intensity is increased to reduce exposure time, then productivity improves, but heat generation causes surface contraction
Solution Approach 1:
The system uses periodic exposure with controlled pulse durations and intervals. Each pulse provides sufficient energy for curing while the intervals allow heat dissipation, preventing cumulative thermal effects that cause surface contraction. This approach maintains short total exposure time while avoiding the surface deformation associated with continuous high-intensity exposure.
Solution Approach 2:
The patent applies dynamics by enabling real-time adjustment of UV LED intensity and exposure timing. The system can dynamically optimize the balance between exposure duration and heat generation based on material properties and environmental conditions, achieving fast curing without surface contraction through adaptive control rather than fixed high-intensity exposure.
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
Reduces heat generation and surface contraction, achieving a printing plate with reduced print gain and improved image integrity by ensuring uniform and controlled actinic radiation exposure.
Implementation Method 1
Photocurable materials generally cross-link (cure) and harden through radical polymerization in at least some actinic wavelength region
Implementation Method 2
exposing the printing element to actinic light from a UV LED light source
Data Source
Figure 1
Figure 2
AI summary
A method of flood exposing a photocurable printing blank to actinic radiation from a UV LED light source, wherein a high intensity UV LED light source is modulated to a lower intensity. The method includes the steps of: (a) positioning the photocurable printing blank in an exposure unit, wherein the exposure unit comprises one or more high intensity UV LED light sources; (b) modulating intensity of the one or more high intensity UV LED light sources to a lower intensity; and (c) flood exposing the photocurable printing blank through the photographic negative or the digitally imaged mask layer to actinic radiation from the one or more modulated UV LED light sources.