Rotatable Heating Member with Movable Magnetic Cores for Uniform Temperature
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Solution Overview
Problem
The existing image heating apparatuses for electrophotographic image forming devices face issues with non-uniform temperature distribution along the lengthwise direction of the fixing member due to deviations in the positional relationship between the magnetic core, excitation coil, and fixing member, leading to inefficient heat generation and potential overheating of the fixing device.
Innovation Solution
The apparatus includes a rotatable heating member, an excitation coil, magnetic cores arranged along the length of the heating member, and a moving mechanism for the core holder to adjust the position of the magnetic cores between two positions, with a stopper to prevent excessive movement, ensuring uniform temperature distribution by maintaining accurate positional relationships between the magnetic cores, excitation coil, and heating member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the magnetic core is moved away from the excitation coil to reduce heat generation at certain portions, then the temperature distribution becomes non-uniform, but the risk of overheating at specific regions is reduced
Solution Approach 1:
The magnetic core is designed to be movable relative to the excitation coil, allowing dynamic adjustment of the positional relationship between the magnetic core and excitation coil. This enables the system to adapt the heat generation distribution by moving the magnetic core to different positions, thereby resolving the contradiction between maintaining uniform temperature distribution and preventing overheating at specific regions
Solution Approach 2:
The system incorporates temperature detection means to monitor the temperature distribution along the fixing member, and based on the detected temperature information, the magnetic core position is adjusted to optimize heat generation distribution. This feedback mechanism ensures uniform temperature distribution while preventing overheating by continuously adapting the magnetic core position according to actual temperature conditions
2Use of energy by moving object
If the protrusion position of the magnetic core is precisely controlled to maintain accurate positional relationship with the excitation coil, then heat generation efficiency is improved, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
Instead of relying solely on precise manufacturing of the protrusion position, the system makes the magnetic core movable, allowing the positional relationship between the magnetic core and excitation coil to be adjusted dynamically. This reduces the stringency of manufacturing precision requirements while maintaining heat generation efficiency through operational adjustment
Solution Approach 2:
The system incorporates detection means that automatically monitors the positional relationship or temperature distribution, and the magnetic core position is adjusted based on this feedback. This self-adjusting mechanism compensates for manufacturing tolerances and maintains optimal heat generation efficiency without requiring extremely high manufacturing precision
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 configuration ensures a uniform temperature distribution along the lengthwise direction of the fixing member, enhancing heat generation efficiency and preventing overheating, thus improving the overall performance and reliability of the image heating process.
Implementation Method 1
an excitation coil provided outside the rotatable heating member and configured to generate heat by electromagnetic induction in the rotatable heating member
Implementation Method 2
a plurality of magnetic cores arranged opposed to the rotatable heating member along a longitudinal direction of the rotatable heating member with the excitation coil interposed therebetween
Data Source
AI summary
An image heating apparatus includes: a rotatable heating member; an coil provided outside the heating member and configured to generate heat by electromagnetic induction in the heating member; a coil holder configured to hold the coil; a plurality of magnetic cores arranged opposed to the heating member along a longitudinal direction of the heating member with the coil interposed therebetween; a core holder configured to hold at least one of the magnetic cores which is movable; and a moving mechanism configured to move the core holder between a first position and a second position which is farther away from the heating member than the first position. The core holder is provided with a stopper portion configured to stop movement of the core holder from the second position to the first position by abutment to the coil holder.