Non-contact Infrared Fixing Temperature Sensing
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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 costs and complexity.
Innovation Solution
A fixing device with a temperature sensing part arranged in a non-contact state, using an infrared sensing element and a condensing member to correct detection temperature based on the temperature difference between them, allowing for precise heating 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 is simplified, but the temperature detection accuracy deteriorates due to temperature difference between the infrared sensing element and the condensing member
Solution Approach 1:
The patent replaces contact-type temperature sensing with non-contact infrared sensing. The infrared sensing element detects infrared rays radiated from the fixing member, and the condensing member focuses these rays onto the sensing element, eliminating the need for physical contact and avoiding temperature differences caused by thermal conduction paths.
Solution Approach 2:
The patent introduces infrared rays as an intermediary carrier of temperature information. Instead of direct thermal contact, the fixing member's temperature is transmitted through infrared radiation to the sensing element, with the condensing member acting as an optical intermediary to focus the radiation.
2Measurement precision
If transmitting members such as condensing mirror and reflecting mirror are provided to locate the temperature sensing part away from the fixing member, then the temperature detection accuracy is improved, but the device complexity and component cost increase
Solution Approach 1:
The patent merges the condensing member and infrared sensing element into an integrated temperature sensing part. This consolidation eliminates the need for separate transmitting members like condensing mirrors and reflecting mirrors, reducing component count while maintaining the ability to detect temperature accurately from a distance.
Solution Approach 2:
The condensing member serves multiple functions: it acts as both the optical element for focusing infrared rays and as part of the temperature sensing assembly itself. This multi-functionality reduces the need for additional dedicated components for each function.
3Measurement precision
If a contact type temperature sensing part such as 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 patent completely replaces contact-type temperature sensing (thermistor) with non-contact infrared sensing. The infrared sensing element detects temperature remotely through infrared radiation, eliminating the need for additional contact sensors and their associated mounting mechanisms.
Solution Approach 2:
The patent uses infrared rays as an intermediary to transmit temperature information from the fixing member to the sensing element without physical contact. This eliminates the need for multiple sensing components and reduces overall system 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 improves temperature detection accuracy and reduces component costs by minimizing the need for additional components and mounting mechanisms, ensuring accurate heating control of the fixing member.
Implementation Method 1
an infrared sensing element sensing infrared rays radiated from the fixing member
Implementation Method 2
a condensing member condensing infrared rays to the infrared sensing element
Data Source
AI summary
A fixing device includes a fixing member, a pressuring member and a temperature sensing part. The fixing member heated by a heat source contacts with a recording medium to heat a toner image on the recording medium. The pressuring member pressures the recording medium to the fixing member. The temperature sensing part in non-contact with the fixing member 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. 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 temperature deference between the infrared sensing element and the condensing member. Heating of the fixing member is controlled with the corrected detection temperature and the control temperature or the detection temperature and the corrected control temperature.