Induction Heating Fixing Roller Uniform Temperature Distribution
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Solution Overview
Problem
Existing image forming apparatuses using induction heating for fixing toner images on recording media often experience temperature distribution issues in the width direction of the fixing roller, leading to inefficient heating and potential faulty fixing due to varied heat dissipation between the center and end portions.
Innovation Solution
A fixing device with a heat generating layer that includes a magnetic layer with a Curie point between 100°C to 300°C, and a low resistance layer, where the eddy current load varies depending on the position in the width direction, ensuring uniform heat generation and distribution across the roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If induction heating is used to heat the fixing roller, then heating speed is improved and energy consumption is reduced, but uniform temperature distribution in the width direction deteriorates due to varied heat dissipation between center and end portions
Solution Approach 1:
The heat generating layer is designed with spatially varying properties: the layer thickness is greater at the center portion and smaller at the end portions in the width direction. This local variation compensates for the different heat dissipation rates, with the thicker center layer generating more heat to offset its higher heat dissipation, while the thinner end layers generate less heat appropriate for their lower heat dissipation rates.
Solution Approach 2:
The invention changes the physical parameter of layer thickness across the width direction of the heat generating layer. By making the layer thickness a variable parameter rather than a constant, the heat generation can be optimized at different positions to achieve uniform temperature distribution while maintaining fast heating speed through induction heating.
2Ease of manufacture
If the heat generating layer has uniform thickness in the width direction, then manufacturing is simplified, but temperature distribution becomes non-uniform due to different heat dissipation at center and end portions
Solution Approach 1:
The heat generating layer implements local quality by having different thicknesses at different positions in the width direction. The center portion has a greater layer thickness while the end portions have smaller layer thicknesses, creating localized heat generation characteristics that match the local heat dissipation patterns to achieve uniform temperature distribution.
3Temperature
If the heat generating layer thickness is increased to compensate for heat dissipation, then temperature uniformity is improved, but energy consumption increases and overheating may occur
Solution Approach 1:
Instead of uniformly increasing the layer thickness across the entire width, the invention applies local quality by increasing thickness only at the center portion where heat dissipation is greatest, while keeping the end portions thinner. This targeted approach reduces overall energy consumption compared to a uniform thickness increase, while still achieving temperature uniformity.
Solution Approach 2:
The invention applies partial action by selectively increasing the layer thickness only where needed (at the center portion) rather than uniformly across the entire width. This prevents excessive heat generation at the end portions and reduces total energy consumption while achieving the necessary temperature uniformity.
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 provides improved heating efficiency and uniform temperature distribution along the fixing roller, preventing excessive heating and ensuring proper fixing of toner images by optimizing the eddy current load and layer thicknesses.
Implementation Method 1
The magnetic flux generator generates a magnetic flux. The heat generating layer generates heat by the magnetic flux generated by the magnetic flux generator
Implementation Method 2
The heat generating layer generates heat by the magnetic flux generated by the magnetic flux generator and has an eddy current load
Implementation Method 3
The Joule heat increases the temperature of the whole fixing roller
Implementation Method 4
The heat generating layer includes a magnetic layer having a Curie point in a range from about 100 degrees centigrade to about 300 degrees centigrade
Data Source
AI summary
An image forming apparatus includes an image carrier to carry a toner image and a fixing device to fix the toner image transferred from the image carrier onto a recording medium by applying at least heat to at least one of the toner image and the recording medium. Such a fixing device includes: a magnetic flux generator to generate a magnetic flux; and a heat generating member disposed at least partially in the magnetic flux. The heat generating member includes a heat generating layer to generate heat via eddy currents therein induced by the magnetic flux, magnitudes of the eddy currents varying according to positions thereof in a width direction of the heat generating layer. Included within the heat generating layer is a magnetic layer having a Curie point in a range, e.g., from about 100 degrees centigrade to about 300 degrees centigrade.