Fixing Device Elastic Pressing Section Nip Pressure Uniformity
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Solution Overview
Problem
Existing belt-type fixing devices face challenges in maintaining consistent nip pressure along the longitudinal direction of the fixing roller, leading to image quality issues and complexity in design and production, with previous solutions either being sensitive to cam shape changes or requiring multiple moving springs that complicate the apparatus.
Innovation Solution
A fixing device with a pressing force transmission section comprising multiple elastic members arranged in the same direction as the pressing section, featuring different elastic coefficients to uniformly distribute pressure and adjust based on recording material type and finishing quality, using an eccentric cam to control the pressurizing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pressurization by a pressing section is increased to increase nip pressure between fixing roller and belt, then nip pressure is increased, but nip pressure on central part is reduced compared with edge portions, causing image quality deterioration
Solution Approach 1:
The pressing section is designed with non-uniform elastic coefficients along the longitudinal direction, with the central portion having a larger elastic coefficient than edge portions. This local differentiation compensates for the natural pressure distribution, ensuring uniform nip pressure across the entire width of the fixing roller when high pressing force is applied.
Solution Approach 2:
The patent changes the elastic coefficient parameter of the pressing section along its longitudinal direction. By making the elastic coefficient vary (larger at center, smaller at edges), the system can maintain consistent nip pressure distribution under different pressing conditions, resolving the contradiction between increasing overall pressure and maintaining uniform distribution.
2Stress or pressure
If a cam is used as pressure applying section with non-uniform surface to compensate nip pressure distribution, then nip pressure distribution is improved, but the design and production become extremely delicate and complex
Solution Approach 1:
Instead of using a geometrically complex cam with non-uniform surfaces, the patent achieves the same pressure distribution effect by changing the elastic coefficient parameter of the pressing section. This parameter-based approach simplifies design and production while maintaining the ability to compensate for pressure distribution variations.
Solution Approach 2:
The patent replaces the mechanical cam system with an elastic pressing section whose material properties (elastic coefficients) are engineered to provide the desired pressure distribution. This substitution eliminates the need for delicate cam surface machining while achieving the same functional result.
3Stress or pressure
If multiple springs are used to adjust pressure distribution in longitudinal direction, then nip pressure uniformity is improved, but the apparatus becomes complicated in structure and large in size
Solution Approach 1:
The patent merges the pressure distribution function into the pressing section itself by varying its elastic coefficients, rather than using separate springs for each position. This integration eliminates the need for multiple independent components and their associated mounting structures, simplifying the overall apparatus.
Solution Approach 2:
The pressing section is designed with spatially varying elastic coefficients, where different regions have different stiffness properties. This local quality differentiation allows the single pressing section to perform the function that would otherwise require multiple springs, reducing structural complexity while maintaining pressure uniformity.
4Manufacturing precision
If pressing force is increased for high-quality fixing, then fixing quality is improved, but pressing force transmission becomes less stable due to cam shape sensitivity
Solution Approach 1:
The patent uses elastic coefficients as controllable parameters to manage force transmission. By designing the pressing section with appropriate elastic coefficient distribution, the system can transmit high pressing forces stably without the sensitivity issues associated with rigid cam mechanisms, ensuring both high fixing quality and reliable force transmission.
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 ensures consistent and adjustable nip pressure distribution, simplifying the device structure, reducing size, and enhancing maintainability while preventing image defects, regardless of recording material type or finishing quality.
Implementation Method 1
a pressing force transmission section which transmits the pressing force generated by the pressure applying section to the pressing section
Implementation Method 2
a pressure applying section which generates the pressing force, and a pressing force transmission section
Data Source
AI summary
A fixing device for conducting fixing by heating and pressurizing a recording material conveyed between a fixing member and a belt, having therein a pressing section that presses the recording material against a fixing member through a belt, a pressure applying section that generates pressing force proceeding to the pressing section, and a pressing force transmission section that is positioned between the pressing section and the pressure applying section and that transmits the pressing force to the pressing section, wherein the pressing force transmission section has plural first elastic members arranged in the same direction as the longitudinal direction of the pressing section, and the first elastic members have a plurality of different elastic coefficients.