Fixing Device Non-Uniform Pressure Belt for Sheet Slippage
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Solution Overview
Problem
The existing fixing devices face sheet slippage issues due to insufficient contact pressure between the pressure belt and the heater, leading to increased complexity in structure when attempting to enhance contact pressure, which can result in failure of sheet conveyance at the entry position.
Innovation Solution
A fixing device with a first and second back up member configuration, where the first back up member provides a higher contact pressure at the first position and the second back up member provides a lower contact pressure at a downstream position, allowing for a simplified structure by maintaining appropriate contact pressure across the nip region without increasing the total load on the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact pressure between the pressure belt and the heater is increased to prevent sheet slippage, then sheet conveyance reliability is improved, but the total load on the fixing device increases and structural complexity increases
Solution Approach 1:
The patent applies different contact pressures at different positions along the pressure belt. The first back up member applies a higher contact pressure at the sheet entry position to prevent slippage, while the second back up member applies a lower contact pressure at the sheet exit position. This local differentiation allows reliable sheet conveyance without requiring high pressure across the entire belt, thereby reducing overall structural complexity.
2Reliability
If a heavy load is applied on the heater to increase contact pressure at the sheet entry position, then sheet slippage is prevented, but the load applied on the entire fixing device becomes larger
Solution Approach 1:
The patent implements non-uniform load distribution by positioning the first back up member closer to the sheet entry position with higher spring constant to provide concentrated pressure where needed, while the second back up member provides reduced pressure downstream. This localizes the heavy load application to only the critical entry region rather than distributing it across the entire fixing device.
Solution Approach 2:
The patent divides the single pressure application point into two separate back up members at different positions along the pressure belt. This segmentation allows independent optimization of pressure at each location, enabling high pressure at the entry position without proportionally increasing the total load on the entire fixing device.
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 prevents sheet slippage at the entry position while maintaining a simplified structure for the fixing device, enhancing heating efficiency and reducing the complexity of the device's design.
Implementation Method 1
a heater (101)
Implementation Method 2
a first back up member (210), and a second back up member (220)
Data Source
AI summary
A fixing device includes a heater, a first endless belt, a first back up member, and a second back up member. The first endless belt provides a nip region upon contacting with the heater, and is movable in a first direction. The first back up member provides a first position where the first back up member nips the first endless belt in cooperation with the heater. The first endless belt and the heater provide a first contact pressure at the first position. The second back up member is positioned downstream of the first back up member in the first direction, and provides a second position where the second back up member nips the first endless belt in cooperation with the heater. The first endless belt and the heater provide a second contact pressure at the second position; the first contact pressure is higher than the second contact pressure.