Induction Fixing Device Flux Generator Magnetic Core Displacement
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Solution Overview
Problem
Electromagnetic induction heating in fixing devices for image forming apparatuses leads to overheating of non-paper-pass-through parts due to low heat capacity and uneven temperature distribution, causing issues like high-temperature offset and damage to components, especially when handling sheets of different sizes and quantities.
Innovation Solution
A fixing device with a flux generator using multiple magnetic cores that can be displaced to adjust the distance from the heating rotation body, controlled by a controller to maintain appropriate temperatures, ensuring the non-paper-pass-through parts do not overheat by varying the magnetic link and heat generation based on sheet size and temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electromagnetic induction heating is used to heat the fixing rotation body, then energy efficiency and warming-up speed are improved, but non-paper-pass-through parts become overheated due to low heat capacity and low heat transfer speed
Solution Approach 1:
The exciting coil is divided into multiple independent coil units along the width direction of the fixing rotation body. Each coil unit can be independently controlled to generate heat in specific regions. This segmentation allows the paper-pass-through part to be heated while reducing or stopping heat generation in non-paper-pass-through parts, thus preventing overheating while maintaining energy efficiency.
Solution Approach 2:
Different regions of the fixing rotation body are assigned different heating characteristics. The paper-pass-through part receives active electromagnetic induction heating to maintain appropriate fixing temperature, while the non-paper-pass-through part has reduced heating or uses heat conduction from adjacent heated regions. This local differentiation resolves the contradiction between energy efficiency and temperature uniformity.
2Loss of time
If the electromagnetic induction heating layer is made extremely thin to achieve high energy efficiency and quick warming-up, then energy efficiency and warming-up speed are improved, but heat transfer speed in traverse direction becomes low causing temperature distribution unevenness
Solution Approach 1:
The heating system is segmented into multiple coil units that can operate independently. This allows localized heating control where thin heating layers provide rapid warming in paper-pass-through regions without causing excessive heat accumulation in non-paper-pass-through regions, effectively managing the heat transfer limitation.
Solution Approach 2:
The heating system dynamically adjusts the operation of individual coil units based on real-time temperature feedback and paper detection. When paper is detected in a region, the corresponding coil unit activates; when no paper is present, heating is reduced or stopped. This dynamic control compensates for the low heat transfer speed of thin layers.
3Adaptability or versatility
If recording sheets of different sizes are passed through in continuation, then versatility is improved, but temperature control becomes difficult due to varying temperature differences between paper-pass-through and non-paper-pass-through parts
Solution Approach 1:
The exciting coil is divided into multiple independently controllable coil units along the width direction. This segmentation enables flexible adjustment of heating zones to match different paper sizes. When smaller sheets are used, only the central coil units corresponding to the paper area are activated, while outer coil units are reduced or stopped, maintaining precise temperature control across varying sheet sizes.
Solution Approach 2:
The system dynamically adjusts which coil units are active based on the detected paper size and position. This dynamic reconfiguration of the heating pattern allows the system to adapt to various sheet sizes while maintaining appropriate temperature distribution, resolving the contradiction between versatility and temperature control precision.
4Temperature
If a long cylindrical center core is used with opening parts to control heating, then temperature control in non-paper-pass-through parts is improved, but the structure becomes complex and cannot flexibly adapt to different sheet sizes and passing sequences
Solution Approach 1:
Instead of a single complex center core with opening parts, the system uses multiple independent coil units that can be selectively activated. This segmentation replaces mechanical structural complexity with electrical control simplicity, achieving the same temperature control function while allowing flexible adaptation to different sheet sizes and passing sequences through software control.
Solution Approach 2:
The mechanical center core rotation and opening mechanism is replaced with an electrical control system that selectively activates different coil units. This substitution eliminates the mechanical complexity of rotating cores and physical opening parts, achieving equivalent temperature control through electronic switching of heating zones.
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 effectively maintains the fixing temperature within a stable range, preventing overheating and ensuring consistent image fixation quality across various sheet sizes and quantities by dynamically adjusting the heat distribution in the electromagnetic induction heating layer.
Implementation Method 1
a fixing rotation body (such as a fixing belt or a fixing roller) having an electromagnetic induction heating layer therein is heated by the electromagnetic induction heating with use of an exciting coil
Implementation Method 2
A fixing device with a flux generator using multiple magnetic cores that can be displaced to adjust the distance from the heating rotation body, controlled by a controller to maintain appropriate temperatures, ensuring the non-paper-pass-through parts do not overheat by varying the magnetic link and heat generation
Data Source
AI summary
A fixing device for thermally fixing image onto recording sheet by causing recording sheet to pass through fixing nip, while heating electromagnetic induction heating layer provided in heating rotation body by flux generated by flux generator including exciting coil located a distance away from circumferential surface of heating rotation body along width direction of heating rotation body. The flux generator includes: magnetic cores arranged to be separated from each other in width direction, to face heating rotation body via exciting coil; holder holding predetermined magnetic cores, arranged in correspondence with non-paper-pass area of heating rotation body, in displaceable state; displacement unit displacing predetermined magnetic cores in predetermined move unit, which is a unit of one magnetic core or a unit of a predetermined number of consecutively placed magnetic cores; and controller controlling displacement unit to displace predetermined magnetic cores in sequence in predetermined move unit.