Magnetic Flake Optical Coating for High-Speed Printing Transfer
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Solution Overview
Problem
The application of magnetically alignable flakes in optically variable devices, such as banknotes, is limited due to poor compatibility with common printing processes like offset and Intaglio printing, which struggle to efficiently transfer and align large magnetic particles.
Innovation Solution
Magnetic flakes are applied to an adhesive surface in the presence of a magnetic field without a liquid binder, allowing for oriented adherence and subsequent thin coating, enabling efficient alignment and maintaining orientation even after the magnetic field is removed, thus creating optically variable devices with enhanced reflectance and color-shifting effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetically alignable flakes are applied using traditional offset or Intaglio printing processes, then the printing process can be used for banknote production, but the large magnetic particles cannot be efficiently transferred or aligned
Solution Approach 1:
The patent extracts the magnetic flakes from the liquid ink binder, applying them as dry particles directly to the adhesive layer. This separation allows the flakes to be freely aligned by magnetic fields without the constraints of traditional printing processes, resolving the contradiction between printing compatibility and alignment precision.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary force to align the magnetic flakes on the adhesive layer. This magnetic field mediator enables precise control of flake orientation without requiring modification of the printing process itself, achieving both ease of manufacture and manufacturing precision.
2Illumination intensity
If a thick layer of magnetic flake suspension is applied to achieve sufficient optical effect, then the optical performance is improved, but the layer thickness increases and compatibility with high-speed printing is reduced
Solution Approach 1:
The patent applies magnetic flakes to the adhesive layer before the top coating is applied, allowing the flakes to be pre-aligned by a magnetic field in a controlled manner. This preliminary action enables sufficient optical effect with a thinner overall layer, improving compatibility with high-speed printing processes.
Solution Approach 2:
The patent changes the physical state of the magnetic flake application from liquid suspension to dry particles, and controls their orientation through magnetic field parameters. This allows for efficient alignment in a thin layer, achieving strong optical effects without increasing layer thickness, thereby maintaining high printing speeds.
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 method allows for the creation of optically variable devices with reduced layer thickness and improved optical effects, such as 3D images, that are compatible with high-speed printing processes, overcoming the limitations of traditional printing methods.
Implementation Method 1
A feature of these products is the ability of the flakes to become oriented along the lines of an applied field inside of a layer of liquid paint or ink
Implementation Method 2
applying magnetic flakes absent any liquid binder or carrier to an adhesive surface in the presence of magnetic field
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2F
AI summary
A method comprising: providing an optically variable device that includes a coating layer, a first substrate, and magnetic flakes, the first substrate including a release layer; adhering the coating layer, of the optically variable device, to a second substrate; and removing the release layer from the optically variable device after adhering the coating layer, of the optically variable device, to the second substrate.