Silicone Rubber Fixing Members Balancing Thermal Conductivity and Hardness
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Solution Overview
Problem
Existing electrophotographic fixing members face challenges in achieving high thermal conductivity while maintaining low hardness and durability, leading to potential breakage or plastic deformation during long-term use.
Innovation Solution
A fixing member with an elastic layer composed of silicone rubber, having a tensile modulus of 0.20 MPa or less and a compressive modulus of 0.19 to 0.57 MPa, with a controlled crosslinked structure that undergoes an initial hardness reduction process, ensuring a compressive modulus change of 5% or lower over 100 hours at 240°C, to prevent breakage and maintain pliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the filler compounding amount is increased to 60 vol % or higher to achieve thermal conductivity exceeding 1.5 W/(m·K), then thermal conductivity is improved, but hardness increases significantly
Solution Approach 1:
The patent applies local quality by creating anisotropic filler arrangement where small particle fillers are concentrated in the thickness direction to enhance thermal conductivity specifically in that direction, while large particle fillers are arranged in the plane direction to maintain flexibility and prevent hardness increase. This spatial differentiation of filler types resolves the contradiction between thermal conductivity and hardness.
Solution Approach 2:
The patent uses composite materials by combining both large particle fillers and small particle fillers in a blended configuration within the elastic layer. This composite approach allows the large particles to provide structural flexibility while small particles provide thermal conduction paths, achieving both low hardness and high thermal conductivity simultaneously.
2Strength
If the tensile modulus is reduced to 0.20 MPa or less to lower hardness, then hardness is improved, but the elastic layer may break or undergo plastic deformation during long-term use
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crosslinking degree of silicone rubber to achieve a specific compressive modulus range (0.19 to 0.57 MPa) while maintaining low tensile modulus (0.20 MPa or less). This parameter optimization ensures the elastic layer remains soft and low-hardness while retaining sufficient durability to prevent breakage during long-term operation.
Solution Approach 2:
The patent uses composite materials by combining silicone rubber with a specific blend of large and small particle fillers. This composite structure allows the silicone rubber matrix to provide flexibility and low hardness while the filler blend provides thermal conductivity and structural support, preventing breakage during long-term use.
3Temperature
If small particle fillers are arranged to form heat conduction paths in the thickness direction to increase thermal conductivity, then thermal conductivity is improved, but the content of thermally-conductive filler must be curtailed
Solution Approach 1:
The patent applies local quality by spatially differentiating filler arrangement: small particle fillers are concentrated in the thickness direction to create efficient heat conduction paths with minimal filler content, while large particle fillers are distributed in the plane direction. This localized arrangement maximizes thermal conductivity in the critical thickness direction while minimizing overall filler content.
Solution Approach 2:
The patent uses another dimension by transitioning from uniform filler distribution to anisotropic arrangement where small particle fillers are oriented specifically in the thickness direction. This dimensional reorganization creates efficient thermal conduction paths without requiring proportional increases in filler content, as the fillers are strategically positioned rather than simply increased in quantity.
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 provides a fixing member with low hardness and excellent durability, enabling stable formation of high-quality electrophotographic images without breakage or deformation, even under high-temperature conditions.
Implementation Method 1
it has become possible to obtain a fixing member having a three-dimensional network structure formed by crosslinking reaction of a silicone rubber
Implementation Method 2
When a gel composition is used for the elastic layer, a three-dimensional network structure is formed by crosslinking reaction of the gel composition, thereby a gel structure having desired elasticity and hardness can be obtained
Implementation Method 3
the unfixed toner becomes heated and pressed, whereby the toner melts and an image becomes fixed onto the recording material
Implementation Method 4
the unfixed toner becomes heated and pressed, whereby the toner melts and an image becomes fixed onto the recording material
Implementation Method 5
with compressive moduli H0 to H100 as respective values of compressive modulus of a cuboid sample 50 mm long, 50 mm wide and 150 μm thick that is sampled from the elastic layer, in a direction corresponding to the thickness direction of the elastic layer, every 10 hours, up to 100 hours, in an atmosphere at a temperature of 240° C.
Implementation Method 6
in an atmosphere at a temperature of 240° C. and at an oxygen concentration of 1% or lower
Data Source
AI summary
An electrophotographic member including a substrate, and an elastic layer on an outer peripheral surface of the substrate; wherein the elastic layer has silicone rubber, a tensile modulus of the elastic layer in a direction perpendicular to a thickness direction thereof is 0.20 MPa or less, a compressive modulus of the elastic layer in the thickness direction is 0.19 to 0.57 MPa, a value (tensile modulus/compressive modulus) of a ratio of the tensile modulus of the elastic layer in a direction perpendicular to the thickness direction, relative to the compressive modulus of the elastic layer in the thickness direction, is 0.80 or lower, and a rate of decrease of each of the compressive moduli of the samples from the elastic layer in a direction corresponding to the thickness direction of the elastic layer is 5% or lower.