Fuser Sliding Surface Roughness for Lubricant Retention
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Solution Overview
Problem
Conventional fixing devices experience scratches on the inner circumferential surface of the second rotatable member due to the irregular sliding surface of the sliding member, leading to lubricant retention issues and increased rotational torque.
Innovation Solution
The sliding member is designed with a surface roughness Ra1 of 0.20 μm or more and a material ratio Rmr of 35% or more, featuring blunt convex portions to reduce scratches and enhance lubricant retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sliding member has an irregular sliding surface, then the lubricant is retained between the sliding surfaces, but scratches occur on the inner circumferential surface of the second rotatable member
Solution Approach 1:
The sliding surface is designed with non-uniform roughness distribution, where the average roughness Ra1 is controlled within 0.03 μm to 3.00 μm. This local quality variation creates optimal lubricant retention in specific areas while minimizing scratch formation on the inner circumferential surface of the second rotatable member.
Solution Approach 2:
The surface roughness parameters of the sliding member are precisely controlled, with average roughness Ra1 between 0.03 μm and 3.00 μm. By changing and optimizing this parameter, the patent achieves both effective lubricant retention and reduced scratch occurrence on the contact surfaces.
2Reliability
If the sliding member has high surface roughness to retain lubricant, then lubricant retention improves, but wear and rotational torque increase
Solution Approach 1:
The patent optimizes the surface roughness parameter Ra1 to fall within 0.03 μm to 3.00 μm. This parameter optimization ensures sufficient lubricant retention while preventing excessive wear and rotational torque increase, achieving a balance between lubricant retention and wear prevention.
Solution Approach 2:
Instead of making the entire sliding surface highly rough, the patent applies controlled roughness only where needed for lubricant retention. The average roughness Ra1 is maintained within a moderate range (0.03-3.00 μm), providing just enough surface irregularity for lubricant retention without causing excessive wear or torque.
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 design effectively reduces scratches on the inner circumferential surface of the second rotatable member, ensuring better lubricant retention and minimizing wear and torque increase.
Implementation Method 1
a lubricant interposed between the inner circumferential surface of the second rotatable member and the sliding member
Implementation Method 2
the sliding member has an irregular sliding surface with a surface roughness Ra1 of 0.03 μm or more and less than 0.30 μm
Data Source
AI summary
A fixing device includes: a first rotatable member; a second rotatable member disposed in contact with the first rotatable member; a pressing member that is disposed along an inner circumferential surface of the second rotatable member and presses the inner circumferential surface of the second rotatable member such that the second rotatable member is pressed against the first rotatable member; a sliding member interposed between the inner circumferential surface of the second rotatable member and the pressing member; and a lubricant interposed between the inner circumferential surface of the second rotatable member and the sliding member. The sliding member has an irregular sliding surface having a surface roughness Ra1 of 0.20 μm or more and a material ratio Rmr of 35% or more.