Selective UV LED Ink Curing for Localized Surface Effects
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Solution Overview
Problem
Existing UV curing technologies for inkjet printing, such as mercury vapor lamps and metal halide bulbs, are inefficient due to long stabilization times, excessive heat production, ozone byproducts, and limited shelf-life, and previous UV-LED solutions fail to create localized curing effects on substrates.
Innovation Solution
Individually controllable UV LEDs are used to cure inks on demand, allowing for different patterns and effects by varying the intensity and timing of UV exposure, either during initial curing or as a post-dosage process, enabling precise control over ink curing on specific areas of a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mercury vapor lamps or metal halide bulbs are used for UV curing, then curing effect is achieved, but excessive heat is produced and ozone is generated
Solution Approach 1:
The patent changes the wavelength parameter of the UV light source by switching from broad-spectrum mercury vapor lamps to narrowband UV-LEDs operating at specific wavelengths (385nm, 395nm, or 405nm). This parameter change eliminates the harmful infrared radiation and ozone generation associated with traditional lamps while maintaining effective UV curing of the ink.
Solution Approach 2:
The patent replaces the thermal-mechanical UV lamp system with a solid-state UV-LED system. This substitution eliminates the need for thermal stabilization, reduces heat generation through efficient electroluminescence, and removes ozone generation by eliminating the arc discharge mechanism that produces ozone in traditional UV lamps.
2Reliability
If mercury vapor lamps or metal halide bulbs are used for UV curing, then curing effect is achieved, but long stabilization time is required after activation
Solution Approach 1:
The patent replaces the thermal-mechanical UV lamp system with a solid-state UV-LED system. LEDs are cold-light sources that emit UV radiation immediately upon electrical activation without requiring thermal stabilization, thereby eliminating the several-minute warm-up period required by mercury vapor lamps and metal halide bulbs.
3Reliability
If UV-LEDs are activated to cure ink, then curing effect is achieved, but all areas with photoinitiator are cured uniformly, preventing localized effects
Solution Approach 1:
The patent segments the UV-LED curing system into multiple independently controllable LED modules, each corresponding to specific print head nozzles or substrate regions. This segmentation allows selective activation of individual LEDs or LED groups to cure only specific areas containing photoinitiator, enabling localized curing effects such as glossy or matte finishes in designated zones while leaving other areas uncured or partially cured.
Solution Approach 2:
The patent implements dynamic control of UV-LED activation states, allowing real-time adjustment of which LEDs are active based on the presence of photoinitiator in specific regions. This dynamic switching capability enables the system to adapt curing patterns to match the spatial distribution of photoinitiator, creating varied surface effects across different areas of the same substrate.
4Ease of manufacture
If traditional substrates are used for printing, then cost is reduced, but entire substrate shows uniform effect preventing area-specific highlighting
Solution Approach 1:
The patent applies local quality by using UV-LEDs to create different surface effects (glossy, matte, or no effect) in specific localized areas of the substrate based on the presence and concentration of photoinitiator. This allows a single uniform substrate to exhibit varied surface characteristics in different regions, eliminating the need for expensive pre-coated substrates while achieving area-specific highlighting and visual effects.
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 allows for cost-effective, energy-efficient, and heat-reduced UV curing with precise control over ink effects, enabling the creation of varied surface characteristics and patterns on a single print, such as glossy and matte effects, without overheating or ozone production.
Implementation Method 1
Another technique for UV curing involves the use of light emitting diodes (LED) that emit UV radiation
Implementation Method 2
The ink is typically cured by exposing ink that contains a photoinitiator to ultraviolet (UV) light
Data Source
AI summary
Individually controllable ultraviolet (UV) light-emitting diodes (LEDs) are used to cure ink and generate different effects. The UV LEDs only expose specified areas to generate the different effect and can create multiple effects on the same substrate by exposing different areas to varying amounts of time or by performing a curing stage and post-dosage curing stages. The different effects include generating a glossy surface, a matte surface, and sharper images.