Pad Sheet Friction Reduction in Image Heating Nip
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Solution Overview
Problem
Existing image heating apparatuses with belt nip type fixing methods face issues of durability due to increased friction between the pad sheet and fixation belt, leading to positional deviations and conveyance errors in recording media, as well as instability in the fixation belt's rotational motion, especially when peripheral velocity changes or in varying temperature and humidity conditions.
Innovation Solution
An image heating apparatus with a pad sheet that includes a low-friction surface layer and a substrate layer with a tensile strength of 300-600 MPa, which reduces friction and maintains durability, and optional knurling to further decrease contact points and retain lubricants, thereby stabilizing the fixation belt's rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a pad sheet with low friction coating is used, then friction between pad sheet and fixation belt is reduced, but the pad sheet wears out faster due to sliding friction
Solution Approach 1:
The invention changes the physical-chemical parameters of the pad sheet surface by applying a fluorinated resin coating with specific friction characteristics. This coating layer modifies the surface properties to achieve low friction while the underlying glass fiber substrate maintains structural integrity and durability, resolving the contradiction between reduced friction and wear resistance.
Solution Approach 2:
The pad sheet is constructed as a composite material system combining glass fiber substrate with fluorinated resin coating. The glass fiber provides mechanical strength and durability, while the fluorinated resin layer provides low friction properties. This composite structure allows simultaneous achievement of both durability and low friction performance.
2Ease of operation
If the fixation belt slides on the pad sheet during fixation, then the fluorinated resin film wears by friction and stretches, but this causes the fixation belt to become unstable in rotation
Solution Approach 1:
The invention modifies the friction parameters of the pad sheet surface through fluorinated resin coating, creating a controlled sliding interface that reduces excessive friction while preventing film stretching. This parameter optimization maintains both the ease of fixation operation and the rotational stability of the fixation belt.
3Object-affected harmful factors
If knurls are added to the pad sheet surface, then the number of contact points between pad sheet and belt is reduced and friction is decreased, but the structure becomes more complex
Solution Approach 1:
The invention introduces knurled patterns (curved/rounded surface features) on the pad sheet surface. These knurls reduce the contact area between the pad sheet and fixation belt, thereby decreasing friction. The curved surface geometry of knurls is achieved through relatively simple molding processes, balancing friction reduction with manufacturing complexity.
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 solution effectively reduces friction between the pad sheet and fixation belt, preventing misalignment and conveyance errors, maintaining belt stability across varying conditions, and enhancing the durability of the pad sheet, thus ensuring consistent image fixation and extended apparatus lifespan.
Implementation Method 1
a surface layer having a low friction property
Implementation Method 2
Knurling the above described pad sheet, that is, a low friction sheet, on the pressure pad, across the surface which faces the belt, can reduce the number of the points of contact between the pad sheet and the inward surface of the belt, reducing thereby the overall friction
Implementation Method 3
the intervals among the knurls on the surface of the pad sheet are effective to hold the lubricant such as oil, contributing to further reducing the friction
Data Source
AI summary
An image heating apparatus includes a heating rotatable member for heating an image on a recording material in a heating nip; a belt for cooperating with the heating rotatable member to form a heating nip; a pad for urging the belt toward the heating rotatable member at the heating nip; and a sheet covering a surface of the pad opposed to the heating rotatable member, the sheet being slidable on the belt, wherein includes a surface layer having a low friction property and a base layer having a tensile strength of 300-600 MPa.