Fixing Belt Surface Layer Yield Stress Control
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Solution Overview
Problem
Existing fixing devices in image forming systems face challenges in maintaining the integrity of the fixing belt's surface layer, particularly in withstanding stress changes during direction alterations, leading to potential damage and reduced durability.
Innovation Solution
A fixing device with a heating roller and an endless fixing belt, where the surface layer's yield stress is increased by heating to a predetermined temperature, ensuring it exceeds the stress applied during direction changes, thus minimizing damage and extending belt life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixing belt operates at room temperature, then the device structure is simple, but the surface layer suffers damage and reduced durability during direction alterations
Solution Approach 1:
The patent changes the temperature parameter of the fixing belt from room temperature to a predetermined temperature (e.g., 150-200°C) where the material's yield stress increases. This parameter change enables the surface layer to withstand stress during direction alterations without damage, resolving the contradiction between reliability and device complexity by using thermal energy already present in the fixing device.
Solution Approach 2:
The fixing belt utilizes its own thermal energy from the fixing process to enhance its structural integrity during direction changes. The heating roller heats the fixing belt during normal operation, and this self-generated heat is then used to increase the yield stress of the surface layer material, eliminating the need for separate heating systems.
2Strength
If the fixing belt material has low yield stress, then the device structure is simple, but the surface layer is vulnerable to stress damage during travel direction changes
Solution Approach 1:
The patent exploits the temperature-dependent property of the material's yield stress. By heating the fixing belt to a predetermined temperature, the yield stress of the surface layer material increases, enabling it to withstand stress during direction alterations. This parameter change approach avoids complex structural modifications while enhancing strength.
Solution Approach 2:
The patent makes the material's mechanical properties dynamic rather than static. The yield stress of the surface layer material changes dynamically with temperature, increasing when heated during direction alterations to prevent damage, and returning to normal state after cooling. This dynamic property adjustment resolves the contradiction between strength and device complexity.
3Adaptability or versatility
If the fixing belt is subjected to frequent direction alterations, then the device is more versatile, but the surface layer experiences increased stress and potential damage
Solution Approach 1:
The patent changes the temperature parameter of the fixing belt to a predetermined level where the material's yield stress is elevated. This enables the surface layer to withstand the stress of frequent direction alterations without damage, allowing the device to maintain high adaptability while preserving surface layer integrity through thermal enhancement.
Solution Approach 2:
The patent applies beforehand cushioning by heating the fixing belt before direction alterations occur. The heating process pre-emphasizes the material's structural integrity, creating a cushioning effect that protects the surface layer from stress damage during subsequent direction changes, thus enabling versatile operation without compromising reliability.
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 prevents damage to the fixing belt's surface layer by maintaining a higher yield stress at elevated temperatures, enhancing the belt's durability and reducing tear growth, even with increased rotations.
Implementation Method 1
a heating roller (48) that is internally provided with a heat source member (62, 64, 66) and is rotated by a drive unit (47), heats the fixing belt (42)
Implementation Method 2
the yield stress of a material forming the surface layer (42C) is varied according to the temperature of the material
Data Source
AI summary
A fixing device includes a heating roller that is internally provided with a heat source member and is rotated by a drive unit; an endless fixing belt that is entrained around the heating roller and heated thereby, and is provided with a surface layer that contacts a recording medium, and the yield stress of a material forming the surface layer is varied according to the temperature of the material; a pressure member that is provided facing the heating roller and presses the recording medium, on which a toner image has been formed, against the fixing belt; a travel direction alteration member that contacts the fixing belt and changes the direction of travel of the fixing belt by bending the fixing belt; and a drive control section that operates the drive unit and rotates the heating roller after the heating roller has been heated such that the endless fixing belt is heated by the heating roller to a predetermined temperature where the yield stress of a material forming the surface layer of the fixing belt is larger than the stress acting on the surface layer when the travel direction of the fixing belt is altered by the travel direction alteration member.