Belt Fixing Device with Zoned Projections for Low-Friction Nips
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Solution Overview
Problem
In wide nip fixing devices, there is a challenge in maintaining adequate frictional forces to prevent slippage between the recording material and the belt and nip portion forming member while minimizing friction between the belt and sliding member, especially in configurations with increased heating efficiency.
Innovation Solution
A fixing device with a rotatable belt and pressing member that includes a contact member with projections on its inner peripheral surface, where the area ratio of contact between the belt and projections outside the nip portion is greater than inside the nip portion, reducing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frictional force between the belt and sliding member is reduced to prevent slippage in wide nip configurations, then the heating efficiency is improved, but the frictional force becomes insufficient to maintain grip on the recording material
Solution Approach 1:
The sliding member is designed with non-uniform friction characteristics: the nip portion has a low friction coefficient to reduce belt friction and improve heating efficiency, while the non-nip portion maintains higher friction to ensure grip on the recording material. This local differentiation resolves the contradiction by optimizing friction properties for different functional zones.
Solution Approach 2:
The sliding member is divided into distinct functional regions: a nip portion that contacts the belt and a non-nip portion that extends beyond. This segmentation allows independent optimization of friction properties in each region, enabling low friction where heating efficiency is critical and high friction where grip is needed.
2Productivity
If the width of the nip portion is widened to increase heating efficiency, then the heating performance is improved, but the frictional force between the belt and sliding member must be minimized more严格要求
Solution Approach 1:
The sliding member incorporates a low-friction coating or material specifically in the nip portion to minimize belt friction, while maintaining normal friction properties in the non-nip portion. This localized approach enables wide nip width for heating efficiency without proportionally increasing overall friction control complexity.
3Device complexity
If irregularities are formed on the sliding sheet to reduce frictional force, then the friction between belt and sliding member is reduced, but wear and lifetime reduction occur
Solution Approach 1:
Instead of changing the geometric shape of the sliding member surface, the invention changes the material parameters by applying a low-friction coating or using a material with inherent low friction properties in the nip portion. This maintains surface integrity and prevents wear while achieving friction reduction.
Solution Approach 2:
A low-friction coating layer is introduced as an intermediary between the belt and the sliding member base material. This coating provides the low-friction interface needed to reduce belt friction without compromising the structural integrity and wear resistance of the underlying sliding member.
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 enhances the lifetime of the fixing device by minimizing wear and maintaining effective frictional forces, preventing slippage, and reducing driving torque.
Implementation Method 1
the recording material passing through the nip portion is heated and pressed
Implementation Method 2
frictional force between the belt and the sliding member is made to be less
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A fixing device includes an endless belt and a contact member contacting an inner surface of the belt in a nip. The contact member includes projections provided on a side where the contact member slides with the belt and to project toward the inner peripheral surface. The projections distribute on and outside the nip in a widthwise direction of a recording material. When in a region where the projections exist, a predetermined region outside the nip in the widthwise direction is a first region, and a region inside the first region and inside the nip is a second region, an area ratio of an contacting area of the belt and the projections in the first region to an area of the first region is larger than an area ratio of an contacting area of the belt and the projections in the second region to an area of the second region.