Reactive Inkjet Printing of Latent Security Images
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Solution Overview
Problem
Current printing systems are inefficient in producing latent images with high resolution, contrast, and control over physical and chemical properties on both porous and non-porous surfaces, and are cumbersome, slow, and expensive, making it difficult to achieve images with hidden patterns in a single-pass operation.
Innovation Solution
A printing system using a reactive ink comprising a silane compound with multiple polymerizable moieties and catalyst compositions that promote polymerization by different mechanisms, allowing for the formation of images with varying physical, chemical, and mechanical properties in a single-pass operation, enabling the creation of latent images with good adhesion on diverse surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional printing systems are used to produce latent images, then the process is cumbersome and slow, but the manufacturing precision and resolution are insufficient
Solution Approach 1:
The printing system divides the ink into multiple separate components (first component with polymerizable monomers and second component with crosslinking agents) that are jetted separately and only combine on the substrate. This segmentation allows each component to be optimized independently while achieving high-resolution latent images through precise control of their separate deposition, resolving the contradiction between precision and productivity.
Solution Approach 2:
The system performs preliminary action by pre-formulating the ink components with specific polymerizable monomers and crosslinking agents that will react upon contact. The latent image pattern is established through selective jetting of these pre-prepared components, which then undergo spontaneous or triggered polymerization to form the final image. This preliminary preparation enables rapid printing without sacrificing the precision of the latent image formation.
2Reliability
If multi-component reactive inks are used to achieve high-resolution latent images, then the system complexity increases, but the adhesion and mechanical properties improve
Solution Approach 1:
The patent merges multiple functional components (polymerizable monomers, crosslinking agents, and optional triggers) into a single integrated inkjet system that handles them as separate but coordinated streams. The components are jetted in a controlled sequence or simultaneously to specific locations, then combine on the substrate to form the printed image. This merging approach achieves reliable adhesion and mechanical properties through the combined action of all components while managing system complexity through unified control architecture.
Solution Approach 2:
The system introduces an optional third component acting as an intermediary or trigger that initiates or accelerates the polymerization reaction between the first and second components. This intermediary enables controlled timing of the chemical reaction, allowing the ink components to be jetted separately without premature reaction, thereby achieving both reliable image formation and manageable system complexity through staged processing.
3Productivity
If single-pass printing is implemented for latent images, then the productivity increases, but the control over physical and chemical properties becomes more difficult
Solution Approach 1:
The printing system applies local quality by enabling different physical and chemical properties in different areas of the printed image through selective jetting of ink components. Each region can receive specific combinations of polymerizable monomers, crosslinking agents, and triggers based on the desired local properties. This spatially selective component distribution allows single-pass printing to produce latent images with varied local characteristics, resolving the contradiction between productivity and manufacturing precision.
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 system enables rapid, flexible, and cost-effective printing of high-resolution latent images with distinct properties, allowing for easy detection through external actions, enhancing security features by producing images with areas of different hardness, rub resistance, and solvent resistance.
Implementation Method 1
a silane compound (A) comprising at least a first and a second polymerizable moiety which are different from each other and are polymerizable by different mechanisms
Implementation Method 2
a first catalyst composition (C1) comprising a substance able to react with the silane compound (A) of composition (RI) and promote the polymerization of the first polymerizable moiety
Implementation Method 3
printing on a substrate using the reactive ink (RI), reticulating a first selected area of the image by ejecting the catalyst composition (C1) onto it
Data Source
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AI summary
A printing system for printing a security feature in the form of a latent image comprising at least three compositions (RI), (C1) and (C2): (RI) a reactive ink comprising a silane compound (A) comprising at least a first and a second polymerizable moiety which are different from each other and are polymerizable by different mechanisms, loaded in a first reservoir of a first printhead, (C1) a first catalyst composition comprising a substance able to react with the silane compound (A) of composition (RI) and promote the polymerization of the first polymerizable moiety, loaded in a second reservoir of said first printhead or of a second printhead, (C2) a second catalyst composition comprising a substance able to react, alone or in presence of composition (C1), with the silane compound (A) of composition (RI) and promote the polymerization of the second polymerizable moiety.