Fuser Thermistor Mounting Structure for Stable Heater Temperature Sensing
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Solution Overview
Problem
Existing fixing devices face issues with temperature detection accuracy due to interference and deformation of insulation sheets around thermistors, leading to unstable contact states and increased errors in heater temperature measurement.
Innovation Solution
A fixing device design that includes a flexible insulation sheet wound around the thermistor, with a cutout in the heater holder to allow the insulation sheet to deform during mounting, ensuring uniform pressure and extended insulation distance to prevent grease intrusion and maintain stable contact with the heater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the insulation sheet is extended to increase insulation distance, then grease intrusion is prevented, but the insulation sheet deforms due to interference with the heater holder
Solution Approach 1:
The patent extracts the interfering portion of the heater holder by providing a cutout at the position that would contact the insulation sheet. This removes the harmful interference while maintaining the extended insulation sheet configuration, allowing the sheet to remain flat and provide adequate insulation distance without deforming.
Solution Approach 2:
The heater holder is segmented by introducing a cutout, which divides the continuous structure into sections. This segmentation creates space for the insulation sheet to pass through or be positioned without interference, maintaining both the extended insulation distance and the flatness of the insulation sheet.
2Reliability
If the insulation sheet is extended to prevent grease intrusion, then protection is improved, but mounting becomes more difficult due to deformation
Solution Approach 1:
By removing the interfering portion of the heater holder through the cutout, the patent eliminates the obstacle that would cause insulation sheet deformation during mounting. This makes the mounting process easier while maintaining the extended insulation sheet configuration for reliable grease protection.
3Measurement precision
If the thermistor contact state with heater is made stable using ceramic paper, then temperature detection stability is improved, but the insulation sheet still interferes and deforms
Solution Approach 1:
The patent removes the interfering portion of the heater holder that would contact and deform the insulation sheet. This allows the insulation sheet to remain flat and maintain proper contact between the thermistor and heater, ensuring stable temperature detection while preventing grease intrusion.
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
Accurate temperature detection of the heater is achieved by maintaining insulation sheet flatness and preventing interference, thereby enhancing the precision of temperature control in the fixing process.
Implementation Method 1
a temperature of a heater heating a fixing film is detected by a thermistor
Implementation Method 2
a temperature of a heater heating a fixing film is detected by a thermistor, heat generated by the heater is controlled
Data Source
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AI summary
In a fixing device (20), a heater holder (24) comes into contact with an end of an insulation sheet (44) and causes the insulation sheet (44) to deform in a process of mounting a thermistor (43) and the insulation sheet (44) in the heater holder (24). Further, in a state in which mounting of the thermistor (43) and the insulation sheet (44) in the heater holder (24) is completed, an inclined surface (24f) releases the end of the insulation sheet (44) from contact with the heater holder (24).