Pressure Roller Reinforcing Member for Fixing Nip Stability
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Solution Overview
Problem
Conventional image forming apparatuses face issues with crumpling prevention and maintenance of a stable fixing performance due to compressive deformation of the resilient layer in the pressure roller, which affects the shape and effectiveness of the fixing nip between the heating and pressure rollers.
Innovation Solution
Incorporating a reinforcing member, such as a disc-shaped or iron core-based structure, to reinforce the resilient layer and prevent compressive deformation, ensuring a consistent fixing nip and maintaining the stability of the fixing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pressure roller is machined to have a reversed-crown shape to prevent sheet crumpling, then the sheet crumpling prevention ability is improved, but the resilient layer is deformed in the axial direction due to spring compression, reducing the pressure roller diameters and weakening the crumple prevention ability
Solution Approach 1:
The patent applies preliminary action by pre-compressing the resilient layer between the shaft and the end surface of the shaft before the pressure roller enters the fixing nip. This pre-compression prevents axial deformation of the resilient layer during operation, maintaining the reversed-crown shape and preventing sheet crumpling. The compressive force is applied in advance through the shaft structure, ensuring the resilient layer maintains its intended geometry throughout the fixing process.
Solution Approach 2:
The patent applies local quality by creating a localized compressed region at the end of the shaft where the resilient layer is pre-compressed. This localized compression maintains the overall reversed-crown shape while preventing axial deformation at critical areas. The shaft structure provides localized support to the resilient layer, ensuring shape stability where it is most needed without affecting the entire pressure roller uniformly.
2Object-affected harmful factors
If the pressure roller is machined to have a reversed-crown shape, then the sheet linear velocity distribution is improved for crumple prevention, but the fixing nip width changes to an unexpected degree, making maintenance of stable fixing performance difficult
Solution Approach 1:
The patent applies preliminary action by pre-compressing the resilient layer between the shaft and the end surface of the shaft before the pressure roller enters the fixing nip. This pre-compression ensures that the pressure roller maintains its intended reversed-crown shape and diameter, resulting in consistent fixing nip width. The compressive force is applied in advance through the shaft structure, preventing dimensional changes during operation and ensuring stable fixing performance.
Solution Approach 2:
The patent applies parameter changes by modifying the compressive force parameter applied to the resilient layer. By adjusting the compressive force between the shaft and the resilient layer, the patent optimizes the pressure roller's dimensional stability. This parameter control ensures that the fixing nip width remains consistent while maintaining the reversed-crown shape for crumple prevention.
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 reinforcing member effectively minimizes compressive deformation of the resilient layer, preventing sheet crumpling and maintaining a stable fixing performance by maintaining the shape and effectiveness of the fixing nip between the heating and pressure rollers.
Implementation Method 1
a resilient layer 6 surrounding the shaft 5... the spring 7 to force the heating roller 3 to be brought into the close contact with the pressure roller 4 by elastically biasing the pressure roller 4 towards the heating roller 3
Implementation Method 2
the toner image is fixed onto the sheet by heat delivered from the heating roller 3
Data Source
AI summary
An image forming apparatus capable of preventing sheets from being crumpled due to compressive deformation of a resilient layer thereof when the sheets pass through a fixing unit, and a method for manufacturing the same. The pressure roller may include a reinforcing member that reinforces a side of the resilient layer to prevent an axial compressive deformation of the resilient layer, a reinforcing member received between the shaft and the resilient layer to increase hardness of the resilient layer, or a reinforcing member interposed between the shaft and the resilient layer to reduce the compressive deformation of the resilient layer.