Demagnetizing Coil Nesting for Electromagnetic Fixing Devices
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Solution Overview
Problem
Conventional electromagnetic induction heating-type fixing devices become large and suffer from reduced demagnetization efficiency when multiple demagnetizing coils are used to accommodate recording sheets of varying sizes, leading to incomplete suppression of over-temperature in the non-sheet-passing region, which can cause thermal degradation.
Innovation Solution
A fixing device with a demagnetizing coil unit comprising a pile of two or more demagnetizing coil units, each with demagnetizing coils of different sizes arranged such that a smaller coil is surrounded by a larger one, extending along the surface of the magnetizing coil, and an operation control unit that adjusts the demagnetizing coils' operation based on the recording sheet's width to effectively cancel magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple demagnetizing coils are provided to accommodate recording sheets of different sizes, then the adaptability to various sheet sizes is improved, but the device size increases and demagnetization efficiency decreases
Solution Approach 1:
The patent applies nesting by placing smaller demagnetizing coils inside larger demagnetizing coils, forming concentric circular patterns. This allows multiple demagnetizing coils of different sizes to occupy the same spatial region rather than being arranged sequentially, thereby preventing device size increase while maintaining adaptability to various sheet sizes.
Solution Approach 2:
The patent transitions from a linear or sequential arrangement of demagnetizing coils to a two-dimensional concentric circular pattern. By utilizing the radial dimension and arranging coils in circles with different radii, the system accommodates multiple sheet sizes without increasing the overall device footprint, as all coils are contained within the same circumferential space.
2Adaptability or versatility
If multiple demagnetizing coils are piled on the magnetizing coil, then the adaptability to various sheet sizes is improved, but the distance between coils increases and demagnetization efficiency is reduced
Solution Approach 1:
The patent applies nesting by placing smaller demagnetizing coils inside larger demagnetizing coils, forming concentric circular patterns. This allows multiple demagnetizing coils of different sizes to occupy the same spatial region rather than being arranged sequentially, thereby preventing device size increase while maintaining adaptability to various sheet sizes.
Solution Approach 2:
The patent transitions from a linear or sequential arrangement of demagnetizing coils to a two-dimensional concentric circular pattern. By utilizing the radial dimension and arranging coils in circles with different radii, the system accommodates multiple sheet sizes without increasing the overall device footprint, as all coils are contained within the same circumferential space.
3Adaptability or versatility
If the number of surrounding demagnetizing coils is increased, then the adaptability to various sheet sizes is improved, but the width of the outermost coil increases and the device becomes large
Solution Approach 1:
The patent applies nesting by placing smaller demagnetizing coils inside larger demagnetizing coils, forming concentric circular patterns. This allows multiple demagnetizing coils of different sizes to occupy the same spatial region rather than being arranged sequentially, thereby preventing device size increase while maintaining adaptability to various sheet sizes.
Solution Approach 2:
The patent transitions from a linear or sequential arrangement of demagnetizing coils to a two-dimensional concentric circular pattern. By utilizing the radial dimension and arranging coils in circles with different radii, the system accommodates multiple sheet sizes without increasing the overall device footprint, as all coils are contained within the same circumferential space.
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 prevents the device from becoming excessively large, maintains high demagnetization efficiency, and effectively suppresses over-temperature in the non-sheet-passing region for a wide variety of recording sheet sizes, preventing thermal degradation.
Implementation Method 1
The magnetizing coil is disposed along an axial direction of the fixing rotating body, and generates an alternating field by passage of alternating current to heat the fixing rotating body by induction
Implementation Method 2
the demagnetizing coil generates magnetic flux in such a direction that part of magnetic flux generated by the magnetizing coil and trying to pass the demagnetizing coil is canceled out
Data Source
AI summary
Provided is a fixing device comprising: a fixing rotating body; a magnetizing coil; a pressing member forming a fixing nip through which a recording sheet passes; a demagnetizing coil unit set including a pile of demagnetizing coil units each including demagnetizing coils of different sizes, and canceling out part of magnetic flux generated by the magnetizing coil in a non-sheet-passing region; a sheet information acquisition unit acquiring sheet information including information relating to a width of the recording sheet; and an operation control unit controlling each demagnetizing coil according to the width, wherein in each demagnetizing coil unit, the demagnetizing coils are arranged such that a smaller demagnetizing coil is surrounded by a larger demagnetizing coil and the demagnetizing coils are in a same plane extending along a surface of the magnetizing coil, and a combination of sizes of the demagnetizing coils differs among the demagnetizing coil units.