Magnetized Roller for Aligning Magnetic Flakes in Printing
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Solution Overview
Problem
Existing methods for aligning magnetic flakes in high-speed printing processes are limited in creating three-dimensional or complex patterns with illusive optical effects, and often require protruding magnets that can damage substrates during contact printing.
Innovation Solution
A rotatable roller with magnetized portions and non-magnetized sections, allowing for a smooth surface contact, is used to orient magnetic flakes in predetermined patterns, enabling the creation of three-dimensional images with an illusion of depth by shaping the magnetic field configuration and using spinning magnets for dynamic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If protruding magnets are used to align magnetic flakes in contact printing, then magnetic field strength is improved, but substrate damage occurs
Solution Approach 1:
A non-magnetic cover layer is introduced as an intermediary between the protruding magnets and the substrate. This cover layer allows the magnetic field to pass through and align the magnetic flakes while preventing direct mechanical contact that would cause substrate damage. The cover layer acts as a protective mediator that decouples the magnetic function from the mechanical contact function.
2Device complexity
If batch processing methods are used for magnetic flake alignment, then pattern complexity is improved, but production speed deteriorates
Solution Approach 1:
The system transitions from static batch processing to dynamic continuous processing. The substrate moves continuously through the printing system while magnets on rotating drums align magnetic flakes in real-time. This dynamic approach enables complex patterns to be formed at high speeds by synchronizing substrate movement with magnet rotation, eliminating the need for batch processing while maintaining pattern complexity.
Solution Approach 2:
The invention implements continuous printing where the substrate moves uninterrupted through the magnetic alignment process. Multiple magnets on rotating drums create continuous magnetic fields that align flakes along the entire substrate width simultaneously. This continuous action eliminates idle time between batches and maintains high productivity while forming complex patterns through coordinated magnet arrangements.
3Ease of operation
If uniform magnetic field is applied, then alignment simplicity is improved, but optical effect dramaticity deteriorates
Solution Approach 1:
Instead of applying a uniform magnetic field, the system uses locally varied magnetic fields created by arrays of discrete magnets arranged in specific patterns on rotating drums. Each magnet creates a localized field that aligns flakes in its immediate vicinity, and the collective arrangement of multiple magnets produces the desired complex optical effects. This local quality approach enables dramatic optical effects while maintaining operational simplicity through standardized magnet arrays.
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 solution allows for high-speed, in-line printing of complex optical effects with uniform substrate contact, enhancing the production of three-dimensional images and illusions of depth without substrate damage, and enabling the formation of continuous images and variable optical effects.
Implementation Method 1
said roller comprising one or more magnetized portions for creating a magnetic field of a predetermined configuration emanating from the outer surface of the roller into the substrate to orient the magnetic flakes in a selected pattern
Implementation Method 2
a magnet rotatably positioned within the cavity for creating a magnetic field of a pre-determined configuration emanating from the outer surface of the roller into the substrate; and a means for spinning the magnet within the cavity during the printing process
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2d
AI summary
A printing apparatus includes a magnetic rotatable roller (710, 810) with a smooth even outer surface for aligning magnetic flakes in a carrier, such as an ink vehicle or a paint vehicle to create optically variable images in a high-speed, linear printing operation. Images can provide security features on high-value documents, such as bank notes. Magnetic flakes in the ink are aligned using magnetic portions of the roller (710, 810), that can be formed by permanent magnets embedded in a non-magnetic roller body, or selectively magnetized portions of a flexible magnetic cover of the roller. Selected orientation of the magnetic pigment flakes can achieve a variety of illusive optical effects that are useful for decorative or security applications.