Printable Reflective Feature Ink Adhesion
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Solution Overview
Problem
Current methods for creating secure features on security documents, such as banknotes, struggle to produce reflective and non-reflective features that are highly secure, durable, and difficult to reproduce, especially with advancements in color copiers and printers, and lack the ability to display variable information effectively.
Innovation Solution
A reflective feature is formed on a substrate with regions of different surface characteristics using metallic nanoparticles, where one region is more adherent than the other, and a process involving direct write printing is used to create a continuous or non-continuous graphical feature that spans multiple regions, incorporating undercoats, overcoats, and specific ink formulations for enhanced reflectivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single ink formulation is used for printing on uniform substrate surfaces, then the printing process is simple and efficient, but the feature cannot be securely differentiated across regions with different surface characteristics
Solution Approach 1:
The patent applies different ink formulations to different regions of the substrate based on their surface characteristics. First ink is used for first substrate surfaces with specific properties, while second ink is used for second substrate surfaces with different properties. This local differentiation ensures optimal adhesion and feature quality across heterogeneous substrate regions without requiring complex universal printing equipment.
Solution Approach 2:
The substrate is divided into multiple regions (first substrate surface and second substrate surface) with different surface characteristics, and each region is treated with a specifically formulated ink. This segmentation allows the printing process to address each region's unique properties independently, achieving secure feature creation across diverse surfaces while maintaining process efficiency.
2Reliability
If conventional printing methods are used, then the printing process is simple, but the reflective features can be easily reproduced by color copiers and printers
Solution Approach 1:
The patent changes the physical and chemical parameters of the ink formulations, specifically using metallic nanoparticles with controlled size distributions (e.g., 40-80 nm for first ink, 80-150 nm for second ink) and different vehicle compositions. These parameter changes create reflective features with unique optical properties that cannot be replicated by conventional color copiers and printers, thereby enhancing security while maintaining manufacturing feasibility.
Solution Approach 2:
The patent employs composite ink formulations containing metallic nanoparticles suspended in specific vehicle compositions. These composite materials provide both the reflective optical properties needed for security features and the adhesion characteristics required for durable attachment to different substrate surfaces, making the features difficult to reproduce while remaining manufacturable.
3Reliability
If standard ink formulations are used for maximum coverage, then the substrate is fully covered, but the durability and reflectivity are reduced
Solution Approach 1:
The patent optimizes the particle size parameters of metallic nanoparticles within specific ranges (40-80 nm and 80-150 nm) to achieve the optimal balance between reflectivity, durability, and coverage. These controlled parameter changes ensure that the ink formulations provide maximum protective coverage while maintaining high reflective properties and long-term durability of the security features.
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 solution provides highly secure, difficult-to-reproduce reflective features with enhanced reflectivity and durability, capable of displaying variable information, effectively addressing the challenges of reproducing secure features on substrates with varying surface characteristics.
Implementation Method 1
a first reflective element, preferably comprising metallic nanoparticles, disposed on the first region; and a second reflective element, preferably comprising metallic nanoparticles, disposed on the second region
Data Source
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AI summary
The invention relates to reflective and non-reflective features formed from multiple inks. In one embodiment, the printed feature comprises a substrate (1) having a first region(2) and a second region(3), the first (2) and second(3) regions having different surface characteristics; a first printed element (14) disposed on the first region (2); and a second printed element (15) disposed on the second region(3), wherein the first printed element (14) is more adherent than the second printed element (15) to the first region (2). In another embodiment, the printed feature comprises multiple layers formed from different inks exhibiting enhanced durability. The invention is also to processes for forming these features, preferably through a direct write printing process.