Induction Heating Rotator with Movable Excitation Coil
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Solution Overview
Problem
Conventional induction heating fixing apparatuses with excitation coils arranged outside the heating rotator experience uneven temperature distribution when the heating rotator is not rotating or rotating at low speed, leading to operational noise and high power consumption due to unnecessary rotation of the pressure roller and heating rotator during preheating.
Innovation Solution
A fixing apparatus with a heating rotator that generates heat through an induced current, an excitation coil positioned outside the rotator, and a relative position changer that adjusts the coil's position relative to the rotator based on whether a toner image is being fixed, allowing for efficient heating without rotating the rotator during preheating by shortening the distance between the coil and the rotator's outer surface when not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the excitation coil is arranged outside the heating rotator to avoid simultaneous replacement, then the coil can be retained during heating rotator replacement, but the temperature distribution becomes highly uneven when the heating rotator is not rotating or rotating at low speed
Solution Approach 1:
The magnetic flux generator is made movable relative to the heating rotator through an eccentric cam mechanism. During preheating (low speed or stationary), the generator is positioned at a first location that provides uniform temperature distribution. During fixing operation (high speed), the generator moves to a second location optimized for heating efficiency. This dynamic positioning resolves the contradiction between ease of repair and temperature uniformity.
2Productivity
If the magnetic flux generator is positioned to cover half the outer circumferential surface during fixing operation, then heating efficiency is improved, but temperature unevenness occurs during preheating when the rotator is stationary or rotating slowly
Solution Approach 1:
The system dynamically adjusts the magnetic flux generator position based on operational mode. During fixing operations, the generator is positioned to cover half the circumferential surface for efficient heating. During preheating, it repositions to provide uniform coverage. This dynamic adaptation allows the system to optimize for productivity during fixing while ensuring temperature uniformity during preheating.
3Temperature
If the pressure roller and heating rotator rotate during preheating to ensure uniform temperature, then temperature uniformity is achieved, but operational noise and power consumption increase
Solution Approach 1:
The movable magnetic flux generator eliminates the need for continuous rotation during preheating. By positioning the generator at an optimized location relative to the stationary or slow-rotating heating rotator, uniform temperature distribution is achieved without the energy cost of rotation. This dynamic positioning capability allows the system to maintain temperature uniformity while minimizing power consumption.
4Productivity
If the excitation coil is arranged inside the heating rotator, then heating efficiency is improved, but the coil must be replaced simultaneously with the heating rotator, increasing cost
Solution Approach 1:
The excitation coil is extracted from the interior of the heating rotator and repositioned outside, forming part of the separate magnetic flux generator assembly. This extraction allows the heating rotator to be replaced independently without affecting the coil, eliminating simultaneous replacement costs while maintaining heating efficiency through the induction heating mechanism.
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 suppresses temperature unevenness in the heating rotator during preheating, reduces operational noise, and minimizes power consumption by allowing the rotator to be efficiently heated without rotation, thus enhancing the overall performance of the image forming apparatus.
Implementation Method 1
Magnetic fluxes generated by excitation coil 522 induce an eddy current in heating rotator 511 made of a metal so that Joule heat is generated. Heating rotator 511 is thus inductively heated.
Implementation Method 2
Magnetic fluxes generated by excitation coil 522 induce an eddy current in heating rotator 511 made of a metal so that Joule heat is generated.
Data Source
AI summary
A fixing apparatus includes a heating rotator which generates heat with an induced current, an excitation coil arranged outside the heating rotator, a pressure roller which rotates with paper being held between the pressure roller and the heating rotator, the paper having a toner image developed thereon, and a relative position changer which changes a relative position of the excitation coil and the heating rotator to a first relative position when the toner image is being fixed to the paper and to a second relative position when the toner image is not being fixed to the paper. In a cross-section perpendicular to a rotation axis of the heating rotator, a distance from a point in an outer circumferential surface of the heating rotator closest to the pressure roller to the excitation coil is shorter at the second relative position than at the first relative position.