Fixing Belt Dual Roughness for High-Speed Toner Separation
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Solution Overview
Problem
Existing fixing devices for image forming apparatuses face challenges in achieving high-speed image formation while maintaining excellent fixability and separability of toner images, as the surface properties of fluororesin-based fixing belts are limited in modifying non-tackiness and releasability, leading to trade-offs in curvature and speed.
Innovation Solution
A fixing belt with a trilayer structure comprising a heat-resistant base layer, an elastic layer, and a release layer made of fluororesin, featuring a first uneven profile with a maximum height roughness of 5.0 to 100 μm and a second uneven profile with a maximum height roughness of 0.5 to 0.9 μm, enhancing non-tackiness and separability, and supported by rollers with a diameter of 50 mm or larger for improved fixability and separability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger roller diameter is used to reduce curvature at the nip portion for high-speed image formation, then image formation speed is improved, but curvature at the exit side decreases making it difficult to achieve both high speed and increased curvature
Solution Approach 1:
The invention applies different surface properties to different regions of the fixing belt. The exit side surface is specifically modified with fluororesin coating and controlled roughness (Ra: 0.3-2.0 μm) to enhance releasability, while the nip portion maintains properties suitable for high-speed fixing. This local differentiation allows the belt to achieve both high-speed performance and adequate exit side curvature even on large diameter rollers.
2Reliability
If fluororesin material is used for the surface layer to improve releasability, then separation performance is improved, but the tendency of fluorine atoms to localize on the surface limits further modification to enhance non-tackiness
Solution Approach 1:
The invention changes the surface parameters of the fluororesin layer by controlling its roughness (Ra: 0.3-2.0 μm) and applying specific coating thicknesses (0.5-5.0 μm). These parameter adjustments optimize the balance between releasability and non-tackiness without requiring chemical modification of the fluororesin material itself, thus avoiding the limitation of fluorine atom localization.
Solution Approach 2:
The fixing belt employs a composite structure with multiple layers: base material layer, elastic layer, and fluororesin surface layer. Each layer contributes different properties - the base material provides structural support, the elastic layer provides compliance, and the fluororesin layer provides releasability. This composite approach allows optimization of each layer independently to achieve both excellent separation and non-tackiness.
3Productivity
If the fixing belt is designed for high-speed operation, then productivity is improved, but maintaining both excellent fixability and separability becomes difficult
Solution Approach 1:
The fixing belt is designed with dynamic characteristics suitable for high-speed operation. The elastic layer provides compliance that allows the belt to adapt to varying speeds and loads. The surface roughness and fluororesin coating are optimized to maintain consistent releasability across different operating speeds, ensuring reliable separation even during high-speed image formation.
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 described configuration enables excellent fixation and separation of toner images even at high speeds, balancing fixability and separability, and maintaining performance across various image formation speeds.
Implementation Method 1
a heater that heats the fixing belt supported by the rollers
Implementation Method 2
a pressure roller disposed to be relatively biased against one of the two or more rollers
Data Source
AI summary
Provided is a fixing belt including a base layer, an elastic layer, and a release layer. The release layer has surface geometry including a first uneven profile and a second uneven profile formed on the surface of the first uneven profile. The first uneven profile is represented as a maximum height roughness, Rz, of 5.0 to 100 μm. The second uneven profile is represented as Rz of 0.5 to 0.9 μm.