Reflector with Localized Low Reflectance for Heater Temperature Control
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face issues with excessive temperature rise of the heater due to infrared light reflection, leading to potential overheating and thermal degradation, especially during continuous use.
Innovation Solution
A fixing device with a reflector having a surface with lower reflectance than the rest, positioned between the fixing member and the heater, to reduce the amount of infrared light reflected back to the heater, thereby preventing excessive temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflector is used to reflect infrared light from the heater toward the nip plate, then the fixing device can be warmed up quickly and energy-saving is improved, but the heater temperature may excessively rise and exceed the upper-temperature limit during continuous use
Solution Approach 1:
The reflector is designed with non-uniform reflectance properties: the first surface (facing the heater) has lower reflectance to reduce heat feedback to the heater, while the second surface (facing the nip plate) has higher reflectance to maximize heating efficiency. This local differentiation of optical properties resolves the contradiction by optimizing each surface's function independently.
Solution Approach 2:
The reflector is divided into two distinct surfaces with different reflectance characteristics. The first surface is optimized for reducing heat feedback to the heater, while the second surface is optimized for reflecting infrared light to the nip plate. This segmentation allows each surface to perform its specific function without compromising the other.
2Productivity
If the heater is used continuously to maintain fixing temperature, then productivity is improved, but the heater temperature may excessively rise and cause thermal degradation
Solution Approach 1:
The reflector's first surface is specifically designed with lower reflectance to reduce the amount of infrared light reflected back to the heater during continuous operation. This localized optical property modification prevents excessive heat accumulation at the heater, enabling continuous high-productivity operation without compromising heater durability.
3Power
If a uniform reflector surface is used to maximize infrared light reflection, then heating efficiency is improved, but the heater receives excessive reflected heat causing temperature rise
Solution Approach 1:
The reflector is designed with spatially varying reflectance properties: the first surface (facing the heater) has lower reflectance to minimize heat feedback, while the second surface (facing the nip plate) has higher reflectance to maximize heating efficiency. This local quality differentiation allows the system to achieve both high heating efficiency and controlled heater temperature.
Solution Approach 2:
The reflector is segmented into two surfaces with different optical properties. The first surface is optimized for reducing heat feedback to the heater, while the second surface is optimized for reflecting infrared light to the nip plate. This segmentation enables the system to simultaneously achieve high heating efficiency and prevent heater overheating.
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 configuration effectively moderates the temperature of the heater, preventing overheating and thermal degradation, while maintaining efficient heating of the fixing member, thus ensuring continuous and reliable operation.
Implementation Method 1
a reflector disposed around the heater reflects infrared light emitted from the heater toward the nip plate
Implementation Method 2
infrared light emitted from the heater reflects toward the nip plate
Implementation Method 3
a heater disposed inside the loop of the fixing member to heat the nip formation pad
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A fixing device (5) comprising a cylindrical fixing member (21), an opposed member (22) disposed opposite an outer surface of the fixing member (21), a nip formation pad (24) disposed inside a loop of the fixing member (21) to sandwich the fixing member (21) with the opposed member (22) to form a nip between the fixing member (21) with the opposed member (22), a heater (23) disposed inside the loop of the fixing member (21) to heat the nip formation pad (24), a reflector (25) which includes a part of a surface facing the heater (23) and having a lower reflectance than the another part of the surface of the reflector (25), wherein at least a part of the reflector (25) is disposed between the fixing member (21) and the heater (23) in a cross-section that intersects the width direction of the fixing member (21) and corresponding image forming apparatus.