Fixing Device Dynamic Clearance Thermal Expansion
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses face challenges in achieving high heating efficiency and preventing wear due to sliding contact between the fixing member and metal member, especially when the apparatus is sped up, leading to issues with warming-up time and printing quality.
Innovation Solution
A fixing device with a flexible endless fixing member and a metal member that is heated by a heating part, where the clearance between them is optimized such that the metal member deforms maximally during warming-up and stabilizes to a smaller deformation during operation, ensuring efficient heating and reducing sliding contact wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the clearance amount between the fixing belt and the metal member is made small to improve heating efficiency, then heating efficiency is improved, but the fixing belt may make sliding contact with the metal member causing wear
Solution Approach 1:
The invention makes the clearance amount dynamic by allowing the metal member to deform elastically in response to thermal expansion during heating. The metal member's flexible structure enables the clearance to automatically adjust: smaller when cold (preventing contact), and larger when hot (accommodating expansion without causing sliding contact).
Solution Approach 2:
The invention changes the physical state of the metal member from rigid to flexible, allowing it to undergo elastic deformation. This parameter change enables the metal member to adapt its shape and position based on temperature, thereby dynamically controlling the clearance amount to simultaneously achieve high heating efficiency and prevent wear.
2Productivity
If the apparatus is sped up to improve productivity, then productivity is improved, but warming-up time and printing quality are affected
Solution Approach 1:
The invention changes the thermal parameters of the system by using a metal member with high thermal conductivity and low heat capacity. This allows the metal member to heat up and expand rapidly, transferring heat efficiently to the fixing belt even at high process speeds, thereby reducing warming-up time while maintaining printing quality.
Solution Approach 2:
The dynamic thermal expansion of the metal member creates a self-regulating system where the clearance automatically adjusts during the heating process. This dynamic behavior enables the system to maintain optimal heating conditions even when the apparatus operates at accelerated speeds.
3Reliability
If the clearance amount between the fixing belt and the metal member is made large to prevent sliding contact, then wear is reduced, but heating efficiency cannot be sufficiently improved
Solution Approach 1:
The invention transforms the static clearance into a dynamic parameter through the elastic deformation of the metal member. The flexible metal member naturally seeks contact with the fixing belt when cold (ensuring high heating efficiency), but elastically deforms upon thermal expansion to prevent harmful sliding contact during operation.
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 results in a shorter warming-up time, improved heating efficiency, and reduced likelihood of wear, ensuring high-quality printing even when the process is accelerated.
Implementation Method 1
a metal member (22) heated by a heating part (25)
Implementation Method 2
a maximum amount of deformation generated in the metal member when heating is started
Implementation Method 3
The fixing belt is heated by the metal member heated by the heater
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A fixing device includes a flexible endless fixing member; a metal member; and a pressing member. "A" is equal to or less than "Bmax" and greater than "Bave" ("Bmax" = "A" > "Bave"), where "A" represents an amount of a clearance at the time of normal temperature between the fixing member and the metal member, "Bmax" represents a maximum amount of deformation generated in the metal member when heating is started by the heating member from a normal temperature state, and "Bave" represents an amount of stable deformation generated in the metal member when the temperature of the entire metal member becomes even.