Induction Heating Coil Segmentation for Paper Width Control
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Solution Overview
Problem
The existing image heating apparatuses experience non-sheet-passing-portion temperature rise when handling small-sized papers, leading to thermal deterioration and improper operation due to wax deposition on moving mechanisms, which requires effective countermeasures.
Innovation Solution
An image heating apparatus with a rotatable heating member, an exciting coil for electromagnetic induction heating, a magnetic flux suppressing member, and a moving mechanism driven by a motor, capable of operating in different current modes and speeds to adjust the magnetic flux distribution based on paper width, thereby controlling heat generation and preventing temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electromagnetic induction heating is used to heat the fixing roller, then heating efficiency is improved and warm-up time is reduced, but non-sheet-passing-portion temperature rise occurs causing thermal deterioration
Solution Approach 1:
The exciting coil is divided into multiple independent coil units arranged along the axial direction of the fixing roller. Each coil unit can be independently controlled to generate magnetic flux in specific regions. This segmentation allows the magnetic flux distribution to match the paper width, concentrating heating only in the sheet-passing portion and avoiding temperature rise in non-sheet-passing portions.
Solution Approach 2:
Different regions of the fixing roller are subjected to different heating intensities based on local needs. The coil units are selectively activated to provide concentrated heating only where paper passes through, while non-sheet-passing portions receive no or minimal heating. This local quality approach ensures efficient heating where needed while preventing thermal deterioration in unused regions.
2Object-affected harmful factors
If a magnetic flux suppressing member is moved to suppress temperature rise, then non-sheet-passing-portion temperature rise is reduced, but wax deposition causes improper operation
Solution Approach 1:
The mechanical moving mechanism for the magnetic flux suppressing member is replaced with a magnetic field-based control system. The coil units themselves are used to suppress magnetic flux in non-sheet-passing portions by controlling the phase and amplitude of alternating current, eliminating the need for physical moving parts. This substitution removes the reliability issue caused by wax deposition on mechanical components.
Solution Approach 2:
The exciting coil serves multiple functions: it generates magnetic flux for heating in sheet-passing portions and simultaneously suppresses magnetic flux in non-sheet-passing portions through phase-controlled alternating current. This multi-functionality eliminates the need for separate magnetic flux suppressing members and their associated moving mechanisms, improving system reliability.
3Temperature
If coil units are arranged to match paper width, then heating distribution is improved, but device complexity increases
Solution Approach 1:
The system uses dynamic control of alternating current phase and amplitude to adjust magnetic flux distribution in real-time based on paper width. Rather than requiring physical reconfiguration of coil units, the system dynamically adapts the electromagnetic field pattern to match different paper sizes, simplifying the mechanical structure while maintaining optimal heating distribution.
Solution Approach 2:
The system changes electrical parameters (phase angle and amplitude of alternating current supplied to different coil units) to control magnetic flux distribution. By adjusting these parameters rather than physically reconfiguring the coil arrangement, the system achieves adaptable heating patterns for different paper widths while keeping the device structure relatively simple.
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 effectively suppresses non-sheet-passing-portion temperature rises and prevents improper operations by ensuring proper movement and cleaning of the magnetic flux suppressing member, maintaining efficient heat distribution and preventing wax adhesion issues.
Implementation Method 1
an exciting coil for causing the rotatable heating member to generate heat by electromagnetic induction heating
Implementation Method 2
heat is generated by Joule heat by generating an eddy current in a fixing roller by a magnetic field generated by an exciting coil
Implementation Method 3
a magnetic flux suppressing member for suppressing a part of magnetic flux acting from the exciting coil onto the rotatable heating member
Data Source
AI summary
An image heating apparatus includes: a rotatable heating member for heating a toner image formed on a recording material by using a toner containing a parting agent; an exciting coil for causing the rotatable heating member to generate heat by electromagnetic induction heating; a magnetic flux suppressing member for suppressing a part of magnetic flux acting from the exciting coil onto the rotatable heating member; a moving mechanism for moving the magnetic flux suppressing member depending on a width size of the recording material; a motor for operating the moving mechanism; and an executing portion capable of selectively executing an operation in a first mode in which a first current is supplied to the motor and an operation in a second mode in which a second current larger than the first current is supplied to the motor.