Fixing Roller Pressure Distribution for Uniform Heat
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Solution Overview
Problem
Existing fixing devices for image forming technologies face challenges in preventing wrinkles and ensuring uniform heat application across the recording sheet, leading to potential image quality issues due to non-uniform heating and transportation speed discrepancies.
Innovation Solution
A fixing device is designed with a pressure distribution mechanism where the elastic pressure member applies greater pressure to the center of the fixing roller and the hard pressure member applies greater pressure to the ends, causing the fixing roller to deform more at the ends, resulting in faster transportation speed and uniform heat application across the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the elastic pressure member applies greater pressure to the center of the fixing roller, then the friction resistance at the center increases and transportation speed becomes slower at the center, but this may cause non-uniform heat application and wrinkle formation
Solution Approach 1:
The pressure distribution is made non-uniform with different characteristics: elastic pressure member provides center-biased pressure while hard pressure member provides end-biased pressure, creating a balanced overall pressure distribution that maintains both speed control and heat uniformity
Solution Approach 2:
The pressure member uses a composite structure combining elastic material and hard material, each contributing different pressure characteristics to achieve the desired balance between transportation speed control and uniform heat application
2Speed
If the pressure belt is pressed more strongly at the center than at the ends, then the transportation speed becomes slower at the center, but this may generate stresses causing wrinkles in the recording sheet
Solution Approach 1:
Different regions of the pressure belt receive different pressure characteristics: the center region receives elastic pressure while the end regions receive hard pressure, creating a balanced stress distribution that prevents wrinkle formation
Solution Approach 2:
The hard pressure member counterbalances the center-biased elastic pressure by applying additional pressure to the end regions, preventing excessive stress concentration that would cause wrinkles
3Force
If the fixing roller surface deforms more at the center, then the friction resistance increases at the center, but this causes non-uniform heat application to the recording sheet
Solution Approach 1:
The pressure distribution is optimized with local variations: elastic pressure at the center provides necessary friction resistance while hard pressure at the ends compensates to maintain overall uniformity, preventing both wrinkles and heat application non-uniformity
Solution Approach 2:
The pressure distribution parameters are carefully controlled with the elastic pressure member positioned at specific distances from the fixing roller surface, creating optimal friction resistance without excessive deformation that would cause heat non-uniformity
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 solution effectively prevents wrinkles and ensures uniform image quality by maintaining consistent heat application and transportation speed across the recording sheet, enhancing the reliability of the fixing process.
Implementation Method 1
the elastic pressure member applies greater pressure to the center of the fixing roller... causing the fixing roller to deform more at the ends
Data Source
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AI summary
Fixing device for fixing image onto recording sheet by applying heat and pressure thereto while it passes through fixing nip, including: pressure belt movable in revolving motion; fixing roller; and pressure member for pressing inner surface of the belt toward the roller. The fixing nip is formed between the roller and belt while elastically deformable surface of the roller is contacted with the belt by pressure applied by pressure member to the belt. The pressure member includes: elastic member for applying pressures so that greater pressure is applied to center of the roller than to ends, the center and ends being along axis direction of the roller; and hard member that is disposed parallel to the elastic member on downstream side thereof in revolving direction of the belt and applies pressures to the roller so that greater pressure is applied to end0s than to center.