UV Curing Method Using LED and Flash Lamp
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current UV printing methods using mercury discharge lamps face challenges such as slow warm-up times, limited power control, toxicity concerns, and high maintenance costs, while LED UV sources struggle with low output efficiency and heat management, leading to complexities and increased costs in achieving consistent print finishes.
Innovation Solution
A method combining partial curing with an LED source and a second curing step using a flash lamp, allowing for controlled UV radiation to achieve both through and surface curing without requiring a nitrogen environment, thereby overcoming the limitations of mercury lamps and LED inefficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a mercury discharge lamp is used for UV curing, then sufficient UV output intensity is achieved, but slow warm-up time and high maintenance costs occur
Solution Approach 1:
The UV curing process is segmented into two distinct stages: a first curing stage using an LED UV source and a second curing stage using a flash lamp. This segmentation allows each light source to be optimized for its specific function, with the LED providing initial curing without requiring warm-up time and the flash lamp providing final intense curing.
Solution Approach 2:
The patent combines two different UV light sources (LED UV source and flash lamp) into a single curing system. This merging allows the system to leverage the advantages of both sources: the LED's immediate operation and the flash lamp's high intensity, thereby eliminating the warm-up time issue while maintaining sufficient UV output.
2Reliability
If a mercury discharge lamp is used for UV curing, then consistent UV output is achieved, but toxicity concerns and environmental disposal issues arise
Solution Approach 1:
The invention extracts and eliminates the harmful mercury element from the UV curing system by replacing the mercury discharge lamp with a combination of LED UV source and flash lamp. This extraction removes the toxicity and environmental disposal issues while maintaining the necessary UV curing functionality through the combined action of the two alternative light sources.
3Productivity
If LED UV source is used for curing, then immediate operation and low power consumption are achieved, but low output efficiency and heat management issues occur
Solution Approach 1:
The patent merges an LED UV source with a flash lamp to create a hybrid curing system. The LED provides immediate operation and low power consumption for the first curing stage, while the flash lamp supplements with high output efficiency for the second curing stage, thereby compensating for the LED's lower output efficiency and heat management limitations.
Solution Approach 2:
The system applies partial curing with the LED UV source first, then completes the curing process with the flash lamp. This partial action approach allows the LED to handle the initial curing demand immediately, while the flash lamp provides the excessive or additional UV energy needed to complete the curing, thereby overcoming the LED's output efficiency limitations.
4Productivity
If high UV power is applied to cure ink droplets, then curing speed is improved, but surface roughness increases and matt image effect occurs
Solution Approach 1:
The curing process is segmented into two stages with different power levels: a first curing stage using lower UV power from the LED source that allows controlled ink flow and merging, and a second curing stage using higher UV power from the flash lamp that completes curing with minimal surface roughness. This segmentation enables both fast curing and smooth surface finish.
Solution Approach 2:
The system applies partial curing with lower UV power from the LED source, allowing the ink to flow and merge properly, then completes the curing with the flash lamp. This partial action at lower power prevents excessive surface roughness while maintaining overall curing speed through the two-stage process.
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 reliable, low-power consumption, and cost-effective UV printing with improved control over print finishes, achieving excellent adhesion and surface cure without the need for nitrogen blanketing, resulting in higher reproducibility and reduced printer complexity.
Implementation Method 1
the ink is exposed to UV radiation emitted from an LED source
Implementation Method 2
The ink, more particularly the photoinitiator provided in the ink, is generally tailored to respond to radiation having the particular wavelength(s) emitted by the UV source
Implementation Method 3
the partially cured ink is exposed to UV radiation emitted from a flash lamp
Implementation Method 4
uses free-radical species to initiate the polymerisation of reactive monomers such as acrylate or methacrylate esters
Data Source
Figure 1
AI summary
The present invention provides a method comprising: applying a UV-curable ink to a substrate; partially curing the ink by exposing the ink to UV radiation from an LED source; and exposing the partially cured ink to UV radiation from a flash lamp. The flash lamp is a xenon or krypton flash lamp. An apparatus for performing the method and an ink adapted for use in the method are also provided.