Fixing Device Gear Thermal Insulation via Sleeve
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face issues with gear melting due to heat transmission through metal shafts, leading to undesirable noise and potential mechanical failure.
Innovation Solution
A fixing device configuration where the first gear is supported by a metal shaft via a sleeve with a higher melting point material, preventing heat-induced melting and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first gear is directly supported by the metal shaft, then the structure is simple, but the gear melts due to heat transmission from the heating roller
Solution Approach 1:
A second gear is introduced as an intermediary component between the first gear and the metal shaft. The second gear rotates together with the first gear about the center of rotation of the first gear, preventing direct thermal contact between the first gear and the heated metal shaft while maintaining the gear transmission function
Solution Approach 2:
The support structure is segmented into multiple components: the metal shaft, the second gear, and the first gear. This segmentation allows the first gear to be thermally isolated from the metal shaft by the second gear, which acts as a thermal barrier while still providing rotational support
2Reliability
If the gear is isolated from the metal shaft using additional components, then heat transmission is reduced, but the device complexity increases
Solution Approach 1:
The second gear is designed to rotate together with the first gear about the center of rotation of the first gear, merging their rotational motion. This combined rotation reduces the number of independent rotational joints needed, simplifying the overall structure while still providing thermal isolation
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 restrains gear melting and noise, ensuring reliable operation by using a sleeve with a higher melting point to insulate the gear from heat transfer through the metal shaft, thereby enhancing the device's durability and quietness.
Implementation Method 1
The sleeve is provided around the metal shaft. A material of the second gear and a material of the sleeve have melting points higher than a melting point of a material of the first gear. The first gear is supported via the sleeve by the metal shaft.
Data Source
AI summary
In a fixing device, a first fixing member and a second fixing member in combination forms a nip, a first gear receives a driving force from a main gear provided in an image forming apparatus, a second gear rotates together with the first gear about a center of rotation of the first gear, a third gear provided in mesh with the second gear rotates together with the first fixing member. The first gear and the second gear are rotatably supported by a metal shaft. The first fixing member and the metal shaft are supported by a side frame. A sleeve is provided around the metal shaft. A material of the second gear and a material of the sleeve have melting points higher than a melting point of a material of the first gear, and the first gear is supported via the sleeve by the metal shaft.