Thermal Fuse Element for Planar Heater Temperature Control
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in effectively detecting temperature variations across the width of the heater to ensure proper fixing of toner images on recording media, particularly when the heater is not in direct contact over its entire length, leading to potential overheating and reduced efficiency.
Innovation Solution
Incorporating a thermal fuse element with a length equal to or greater than the image forming width, supported by elastic members, which is in contact with a planar heater and can detect temperature increases across the heater's width, ensuring the heater maintains a stable temperature and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heater is not in direct contact over its entire length, then the device complexity is reduced, but the temperature control reliability deteriorates due to potential overheating
Solution Approach 1:
The patent introduces a thermal fuse element as an intermediary component between the heater and the recording medium. This thermal fuse element makes contact with the heater over its entire length and serves as a mediator to detect temperature variations, thereby ensuring reliable temperature control without requiring the heater to be in direct contact over its entire length with the recording medium.
Solution Approach 2:
The patent replaces the mechanical direct contact system (heater directly contacting the recording medium) with a thermal detection system. The thermal fuse element, which has electrical conductivity, substitutes the mechanical contact arrangement by using thermal and electrical properties to detect temperature variations, thereby ensuring reliable temperature control.
2Measurement precision
If the thermal fuse element length is increased to cover the entire heater width, then the temperature detection precision is improved, but the device complexity increases
Solution Approach 1:
The patent makes the thermal fuse element serve multiple functions: it acts as both a structural support component and a temperature detection element. By giving the thermal fuse element electrical conductivity, it can detect temperature variations across the entire heater width without requiring additional separate sensing components, thereby improving temperature detection precision while avoiding increased device complexity.
Solution Approach 2:
The patent changes the physical parameter of the thermal fuse element by giving it electrical conductivity. This parameter change allows the thermal fuse element to function as both a structural component and a temperature sensor, enabling it to detect temperature variations across the heater width without increasing structural complexity.
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 effective temperature detection and control across the heater's width, ensuring consistent fixing of toner images and preventing overheating, thus maintaining the device's operational efficiency and reliability.
Implementation Method 1
The thermal fuse element has ends, has a length equal to or larger than an image forming width of the toner image formed on the recording medium, and is in contact with the heater
Implementation Method 2
The elastic member supports at least one of the ends of the thermal fuse element
Implementation Method 3
The heater heats the endless belt
Data Source
AI summary
A fixing device includes an endless belt, a planar heater, a thermal fuse element, and an elastic member. The belt fixes a toner image to a recording medium. The heater heats the endless belt. The thermal fuse element has ends, has a length equal to or larger than an image forming width of the toner image formed on the recording medium, and is in contact with the heater. The elastic member supports at least one of the ends of the thermal fuse element.