Rotating Magnetic Field Generator for Optical Effect Layers
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Solution Overview
Problem
Existing magnetic orienting devices for printing and coating equipment are limited by mechanical constraints, preventing the use of rotating strong magnets within the constrained space of sheet-fed and web-fed rotating printing machines, necessitating a modular and robust solution for generating a rotating magnetic field.
Innovation Solution
A method and apparatus utilizing a spinable permanent magnet assembly and an electromagnet assembly to create a rotating magnetic field, where the permanent magnet assembly generates a strong magnetic field that is interacted with by a weaker oscillating or rotating field from the electromagnet assembly to orient magnetic or magnetizable pigment particles in a coating composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a strong permanent magnet assembly is used to generate a magnetic field for orienting pigment particles, then the magnetic field strength is sufficient for effective particle orientation, but the device becomes too large and complex to fit within the constrained space of rotating printing machines
Solution Approach 1:
The patent combines the functions of a strong permanent magnet assembly and a rotating magnetic field generator into a single integrated device. The permanent magnet assembly generates a strong static magnetic field, while electromagnets or permanent magnets mounted on a rotating element superimpose a rotating magnetic field component, achieving both strong field strength and rotational capability within a compact volume suitable for printing machines.
Solution Approach 2:
The patent introduces dynamic rotation of a subset of magnets (electromagnets or permanent magnets on a rotating element) within the magnet assembly. This rotating component generates a time-varying magnetic field that interacts with the static field from permanent magnets, creating the necessary rotating magnetic field for particle orientation while maintaining a compact overall structure.
2Reliability
If multiple separate magnetic field generators are used to create a rotating magnetic field, then the required magnetic field effects are achieved, but the device complexity and power consumption increase significantly
Solution Approach 1:
The patent merges the functions of multiple magnetic field generators into a single integrated assembly where permanent magnets provide a strong static field and a rotating element with electromagnets or permanent magnets provides the rotating field component. This unified structure reduces overall device complexity while maintaining the capability to generate the required rotating magnetic field for effective particle orientation.
3Speed
If a rotating magnetic field is generated using traditional electromechanical methods, then the magnetic field rotation is achieved, but the power consumption and mechanical complexity increase
Solution Approach 1:
The patent replaces traditional electromechanical rotation mechanisms with a magnetic field-based rotation system. Electromagnets or permanent magnets mounted on a rotating element are actuated by controlled currents to generate a rotating magnetic field, which interacts with the permanent magnet assembly to achieve magnetic field rotation without requiring complex mechanical drive systems, thereby reducing power consumption and mechanical complexity.
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 the production of optical effect layers with a compact and low-power arrangement, reducing the need for multiple magnetic fields and enabling the creation of dynamic, rotationally symmetric optical effects on security documents and other substrates.
Implementation Method 1
A method and apparatus utilizing a spinable permanent magnet assembly and an electromagnet assembly to create a rotating magnetic field, where the permanent magnet assembly generates a strong magnetic field that is interacted with by a weaker oscillating or rotating field from the electromagnet assembly to orient magnetic or magnetizable pigment particles in a coating composition.
Implementation Method 2
coatings or layers containing magnetic or magnetizable pigment particles, particularly also optically variable magnetic or magnetizable pigment particles, for the production of security elements
Data Source
Figure 1a~1c
Figure 2a~2b
Figure 2c~2d
AI summary
The present invention relates to the field of the protection of value documents and value commercial goods. In particular, the invention relates to methods of making an optical effect layer (OEL) associated with a substrate, the method comprising i) providing a substrate associated with a coating composition comprising magnetic or magnetizable pigment particles; ii) providing a permanent magnet assembly producing a first magnetic field; iii) providing an electromagnet assembly including a winding assembly and drive producing an oscillating or rotating second magnetic field that interacts with the first magnetic field to spin the permanent magnet assembly to rotate the first magnetic field; and iv) applying the first magnetic field whilst the first magnetic field rotates by spinning of the permanent magnet assembly to aggregately orient the magnetic or magnetizable pigment particles to create the optical effect layer. The invention also relates to apparatuses for creating an OEL.