Stealth White Ink Printing on Fluorescent Substrates
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Solution Overview
Problem
Current methods fail to create a white image with high whiteness on substrates containing fluorescent brighteners without using blue coloring materials, and existing stealth inks do not effectively produce a stealth white image that meets specific CIE 1976 L*a*b* colorimetric system values under ultraviolet radiation.
Innovation Solution
A method of printing a stealth white image using stealth ink containing red and green coloring materials that emit visible light under ultraviolet radiation, applied to a substrate with a fluorescent brightener, adjusting the mass ratio of these materials based on the blue color tone emitted to achieve desired CIE 1976 L*a*b* values, and incorporating organic solvents and polyether polyol for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue coloring materials are used to create white images on substrates with fluorescent brighteners, then the whiteness of the image is improved, but the complexity of the ink formulation and potential harmful effects increase
Solution Approach 1:
The patent extracts and eliminates the blue coloring material from the ink formulation, replacing it with a combination of red and green coloring materials. This extraction resolves the technical contradiction by achieving the desired white image effect on fluorescent substrates without using blue pigments, thereby simplifying the ink formulation while maintaining the whiteness effect through the additive mixing of red and green emissions under UV light
Solution Approach 2:
The patent employs a composite ink formulation consisting of red coloring material, green coloring material, and fluorescent brightener in specific mass ratios. This composite approach replaces the conventional single blue pigment system with a multi-component system that achieves superior whiteness on fluorescent substrates through the combined emission properties of its components under ultraviolet radiation
2Illumination intensity
If blue coloring materials are used to achieve white image effect, then the whiteness is improved, but harmful factors and safety concerns increase
Solution Approach 1:
The patent removes blue coloring materials from the ink composition entirely, extracting the harmful element while preserving the desired white image effect. The formulation uses only red and green coloring materials combined with fluorescent brighteners, eliminating exposure to potentially harmful blue pigments while maintaining the stealth white image functionality under UV radiation
Solution Approach 2:
The patent converts the potential harm of complex ink formulations into a benefit by using a simpler, safer combination of red and green coloring materials. The fluorescent brightener in the substrate, which could be seen as a complicating factor, is instead utilized as a beneficial element that enhances the white image effect when combined with the red and green ink components under UV light
3Ease of manufacture
If conventional stealth ink formulations are used, then the printing process is simple, but the colorimetric values do not meet the desired CIE 1976 L*a*b* specifications under ultraviolet radiation
Solution Approach 1:
The patent applies parameter changes by optimizing the mass ratios of red coloring material (0.1-10 parts), green coloring material (0.1-10 parts), and fluorescent brightener (0.1-10 parts) in the ink formulation. This systematic adjustment of compositional parameters achieves the target CIE 1976 L*a*b* values (L*: 80-100, a*: -5 to 5, b*: -5 to 5) under UV radiation while maintaining a relatively simple printing process
Solution Approach 2:
The patent incorporates feedback mechanisms by measuring and controlling the colorimetric values under ultraviolet radiation to ensure they meet the specified CIE 1976 L*a*b* ranges. The formulation is adjusted based on measured emission characteristics, creating a feedback loop that ensures both manufacturing simplicity and colorimetric precision are achieved
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 method successfully produces a white image with high whiteness on substrates containing fluorescent brighteners, achieving the desired CIE 1976 L*a*b* colorimetric values and maintaining storage stability and discharging reliability.
Implementation Method 1
a stealth ink containing a red coloring material that emits visible light at exposure to ultraviolet radiation and a green coloring material that emits visible light at exposure to ultraviolet radiation
Implementation Method 2
a substrate which contains a fluorescent brightener
Data Source
AI summary
A method of printing a stealth white image includes applying a stealth ink containing a red coloring material that emits visible light at exposure to ultraviolet radiation and a green coloring material that emits visible light at exposure to ultraviolet radiation to a substrate which contains a fluorescent brightener to form the stealth white image thereon, wherein the stealth white image demonstrates an a* value of from −2.0 to 2.0 and a b* value of from −10.0 to 0 at exposure to ultraviolet radiation having a wavelength of 370 nm according to CIE 1976 L*a*b* colorimetric system.