Induction Fixing Roller Magnetic Flux Saturation Control
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Solution Overview
Problem
Reducing the size of the rotational heating member in electromagnetic induction fixing devices to minimize size and thermal capacity increases the risk of magnetic flux saturation, leading to decreased inductance and potentially damaging electric currents, which prolongs the startup time of the fixing device.
Innovation Solution
A fixing device with a rotatable member having an electroconductive layer and a helical coil, where a magnetic member is configured inside the coil, and a controller limits the maximum electric power supplied to the coil based on the temperature of the magnetic member to prevent magnetic flux saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the core size is reduced to minimize fixing device size and thermal capacity, then the device size and thermal capacity are reduced, but the core becomes saturated with magnetic flux more easily, causing inductance decrease and potential damage to the electric power source
Solution Approach 1:
The patent applies dynamic control by varying the maximum amount of magnetic flux allowed to be generated based on the core temperature. As the core temperature increases, the saturation point changes, so the control section dynamically adjusts the magnetic flux limit accordingly. This allows the system to operate with a smaller core while preventing saturation through real-time adaptation.
Solution Approach 2:
The patent changes the parameter of maximum magnetic flux amount based on core temperature conditions. By monitoring temperature and adjusting the magnetic flux parameter dynamically, the system can use a smaller core without risking saturation. This parameter change approach resolves the contradiction between small size and saturation prevention.
2Reliability
If the maximum amount of magnetic flux is limited to prevent core saturation, then core saturation is prevented, but the startup time of the heating device increases
Solution Approach 1:
The control section dynamically adjusts the maximum magnetic flux amount based on real-time core temperature measurements. During startup when the core is cold, higher magnetic flux can be applied for faster heating. As the core approaches saturation temperature, the system dynamically reduces the flux limit to prevent saturation. This dynamic approach minimizes startup time while ensuring reliability.
Solution Approach 2:
The system performs preliminary temperature assessment and pre-adjusts the magnetic flux limit before saturation occurs. By monitoring temperature and proactively controlling the flux amount in advance, the system prevents saturation while maintaining optimal heating rate during startup, thus reducing overall startup time.
3Quantity of substance
If the core size is reduced to reduce thermal capacity, then the thermal capacity is reduced, but the point of magnetic flux saturation decreases, making the core more susceptible to saturation
Solution Approach 1:
The patent employs feedback control by continuously monitoring the core temperature and using this information to adjust the maximum magnetic flux amount. The temperature detection section provides real-time feedback to the control section, which then adapts the flux limit to prevent saturation. This feedback mechanism allows the system to operate safely with reduced thermal capacity.
Solution Approach 2:
The system changes the operating parameters by adjusting the magnetic flux amount based on the core's thermal state. With a smaller core having lower thermal capacity and lower saturation point, the system adapts by modulating the magnetic flux parameter in real-time according to temperature feedback, enabling safe operation at reduced size.
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 a smaller, more efficient fixing device that can reach fixation temperature quickly, maintaining thermal efficiency while preventing magnetic flux saturation, thus reducing the First Print Out Time.
Implementation Method 1
The electroconductive layer generates heat by electromagnetic induction caused by the magnetic flux produced by an alternating current through the coil
Implementation Method 2
the magnetic flux produced by an alternating current through the coil
Data Source
AI summary
A fixing device fixes an image on a sheet, and includes a rotatable member having an electroconductive layer; a helical coil provided inside the rotatable member and having a helix axis extending in a generatrix direction of the rotatable member; a magnetic member provided inside a helical configuration portion formed by the coil, the magnetic member not forming a loop outside the rotatable member; and a controller for controlling electric power supplied to the coil. The electroconductive layer generates heat by electromagnetic induction caused by the magnetic flux produced by an alternating current through the coil to fix the image on the sheet by the heat from the rotatable member. The controller limits the maximum electric power supplied to the coil, in accordance with the temperature of the magnetic member.