Fuser Heater Layout for Faster Abnormal Temperature Detection
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Solution Overview
Problem
Existing fixing devices fail to timely detect abnormal temperature rises in the small heat distributed area, leading to potential breakdown due to excessive heating.
Innovation Solution
A fixing device with a heater divided into short and long regions, where temperature detection members are strategically placed to monitor and control temperature, including a heat source detection member in the short region and a power interrupting member in the long region, ensuring timely detection and prevention of excessive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the end-side thermistor is provided in the small heat distributed area to detect temperature, then the fixing device can detect temperature inside the fixing device, but the temperature in the small heat distributed area rises later than in the large heat distributed area, causing delayed detection of abnormal temperature rise
Solution Approach 1:
The patent introduces a thermal conductor as an intermediary element that transfers heat from the heater to the end-side thermistor. This thermal conductor acts as a heat bridge, allowing the thermistor to detect temperature changes in the large heat distributed area (where temperature rises quickly) while still monitoring the small heat distributed area, thereby resolving the timing delay in temperature detection.
2Power
If the heater has a large heat distributed area on one side and small heat distributed area on the other side, then the heater can provide effective heating, but the temperature distribution becomes uneven causing detection delays in the small heat distributed area
Solution Approach 1:
The thermal conductor serves as a mediator that equalizes temperature distribution across the heater. By conducting heat from the large heat distributed area to the small heat distributed area, it ensures more uniform temperature distribution while maintaining the heater's effective heating capability.
3Reliability
If the end-side thermistor is placed in the small heat distributed area, then it can monitor that specific region, but it cannot timely detect abnormal temperature rise leading to potential breakdown
Solution Approach 1:
The thermal conductor enables the end-side thermistor to detect temperature changes more rapidly by providing a direct heat conduction path from the heater. This reduces the detection time for abnormal temperature rises, thereby improving the reliability and safety of the fixing device without sacrificing detection capability in the small heat distributed area.
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 prevents damage from excessive heating by timely detection and control, allowing for efficient and safe operation of the fixing device, reducing downtime and ensuring proper image fixation.
Implementation Method 1
The heater has a substrate and a resistance heating element
Implementation Method 2
The heat source temperature detection member detects a temperature of the heater
Data Source
AI summary
A fixing device includes a fixing belt, a pressure member, a heater, and a heat source temperature detection device. The heat source temperature detection member detects a temperature of the heater. The heater includes a substrate and a heat generating part. The substrate extends in an axial direction of the fixing belt. The heat generating part is formed at a position shifted in one direction from a center in the axial direction on one surface of the substrate facing the pressure region, and generates heat when being powered. The heater is divided into a short region having a shorter length in the axial direction and a long region having a longer length in the axial direction by the center of the heat generating part in the axial direction as a boundary. The heat source temperature detection member is disposed in the short region of the heater.