Fixing Device With Exposed Thermistors for Rapid Overheat Detection
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses lack effective mechanisms for quickly and accurately detecting abnormal temperatures to prevent overheating, which can lead to damage and inefficiencies.
Innovation Solution
The fixing device incorporates a power interrupter with multiple temperature responsive elements, including thermistors with temperature compensation, that are externally exposed for easy assembly, detection, and replacement, ensuring rapid power cutoff to heaters when abnormal temperatures are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature responsive elements are placed inside the fixing device, then temperature detection is integrated into the system, but detection accuracy and accessibility are reduced
Solution Approach 1:
The temperature responsive elements are extracted from the internal structure of the fixing device and mounted on its external surface. This allows the elements to directly detect the temperature of the fixing rotator through thermal conduction while maintaining simple integration. The extraction principle resolves the contradiction by improving detection accuracy through direct external contact while avoiding the complexity of internal embedding.
2Ease of operation
If temperature responsive elements are externally exposed, then detection accuracy and accessibility improve, but assembly and maintenance complexity increases
Solution Approach 1:
The fixing device is segmented into functional modules, with temperature responsive elements mounted as separate components on the external surface of the fixing device housing. This modular approach allows independent installation, replacement, and calibration of temperature elements without disassembling the entire fixing device, thereby improving accessibility while maintaining manufacturing simplicity.
3Reliability
If multiple temperature responsive elements are used, then temperature monitoring reliability improves, but device complexity and cost increase
Solution Approach 1:
Multiple temperature responsive elements are merged into a single external mounting structure on the fixing device housing. This consolidation allows multiple sensing elements to be positioned at different locations for comprehensive temperature monitoring while sharing common mounting hardware and electrical connections, thereby improving reliability through redundant sensing without proportionally increasing device 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 design enhances temperature detection accuracy and reliability, preventing overheating and reducing the risk of device damage while maintaining operational efficiency and cost-effectiveness.
Implementation Method 1
a temperature responsive element, and a fastener. The pressure rotator presses the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The heater heats the fixing rotator. The temperature responsive element is exposed outside the fixing device and fixed to the fastener
Implementation Method 2
The heater heats the fixing rotator
Data Source
AI summary
A fixing device includes a fixing rotator, a pressure rotator, a heater, a temperature responsive element, and a fastener. The pressure rotator presses the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The heater heats the fixing rotator. The temperature responsive element is exposed outside the fixing device and fixed to the fastener. The fastener is exposed outside the fixing device.