Fixing Device Temperature Sensing With Air Blow Control
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Solution Overview
Problem
Conventional image forming apparatuses face inaccuracies in temperature detection of the fixing member due to temperature differences between the infrared sensing element and the condensing member, leading to incorrect heating control and increased component complexity and cost.
Innovation Solution
Incorporating an air blow controlling part to adjust the air flow to the temperature sensing part, which corrects the detection temperature based on the temperature difference between the infrared sensing element and the condensing member, ensuring accurate temperature measurement and control of the fixing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the temperature sensing part is located at a position receiving the effect of heating of the fixing member, then the temperature detection can be simplified without additional transmitting members, but the temperature detection accuracy deteriorates due to temperature difference between the infrared sensing element and the condensing member
Solution Approach 1:
An air blow controlling part is introduced as an intermediary to blow air toward the temperature sensing part. This air flow acts as a mediator to equalize the temperature between the infrared sensing element and the condensing member, eliminating the temperature difference that causes detection errors. The air blow controlling part includes a blowing hole that directs air flow to cool both components uniformly.
Solution Approach 2:
The temperature parameter of the temperature sensing part is actively controlled by changing the air flow condition. By adjusting the air blow strength and direction, the temperature of the infrared sensing element and condensing member is modified to eliminate temperature differences. This dynamic parameter adjustment ensures accurate temperature detection without requiring complex structural arrangements.
2Measurement precision
If a condensing mirror and reflecting mirror are provided to locate the temperature sensing part at a position not affected by heating, then the temperature detection accuracy is improved, but the device complexity and component cost increase
Solution Approach 1:
The complex optical transmitting members (condensing mirror and reflecting mirror) are removed from the system. Instead of using these optical components to redirect infrared rays away from the heating source, the patent extracts this function and replaces it with a simpler air blow controlling part that directly cools the temperature sensing part, eliminating the need for mirrors and their mounting mechanisms.
Solution Approach 2:
A pneumatic system (air blow controlling part) is used to replace the optical system (mirrors). By introducing controlled air flow to cool the temperature sensing part, the patent substitutes complex optical transmitting members with a simpler pneumatic control mechanism, reducing component quantity and device complexity while maintaining detection accuracy.
3Measurement precision
If a direct measuring thermistor is added to correct the detection temperature, then the temperature detection accuracy is improved, but the component cost and device complexity increase
Solution Approach 1:
The temperature sensing part performs self-correction by using the air blow controlling part to equalize its own temperature. Instead of adding a separate correction sensor (direct measuring thermistor), the system uses the air flow mechanism to actively maintain the infrared sensing element and condensing member at the same temperature, eliminating the need for additional correction components.
Solution Approach 2:
A mechanical correction approach (adding direct measuring thermistor) is replaced with a thermal control approach (air blow controlling part). By using air flow to actively manage the temperature environment of the sensing part, the patent eliminates the need for mechanical correction sensors and their mounting mechanisms, reducing component quantity while improving detection accuracy.
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 improves the accuracy of temperature detection and control of the fixing member, reducing component complexity and cost by eliminating the need for additional transmitting members and mounting mechanisms, while ensuring precise heating control.
Implementation Method 1
an infrared sensing element sensing infrared rays radiated from the fixing member
Implementation Method 2
a condensing member condensing the infrared rays to the infrared sensing element
Implementation Method 3
The air blow controlling part is configured to control execution and stop of the air blow to the temperature sensing part
Data Source
AI summary
A fixing device includes a fixing member, a pressuring member, a temperature sensing part and an air blow controlling part. The fixing member heated by a heat source heats a toner image on the recording medium. The temperature sensing part includes an infrared sensing element sensing infrared rays from the fixing member and a condensing member condensing the infrared rays to the infrared sensing element. The air blow controlling part executes and stops the air blow to the temperature sensing part. Detection temperature of the fixing member is calculated with a sensing value by the infrared sensing element. The detection temperature or control temperature of the heat source is corrected with air blow condition by the air blow controlling part and temperature deference between the infrared sensing element and the condensing member. Heating of the fixing member is controlled with the corrected detection temperature or the corrected control temperature.