Fixing Roller Elastic Layer Nip Width and Warm-up Trade-off
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Solution Overview
Problem
Conventional belt fixing type fixing devices face challenges in achieving excellent fixation properties for toner images with significant toner amounts on recording papers with uneven surfaces, and they often require longer warm-up times and increased power consumption due to low heat conductivity of the elastic layer.
Innovation Solution
A fixing device with an endless fixing belt, a heating roller, and a fixing roller with an elastic layer that has a pressing rate of 40% or more and Asker C hardness between 20 and 30 degrees, allowing for improved followability and heat distribution, along with a repulsive rate of 65% or more to enhance peeling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the elastic layer of the elastic roller is thickened to widen the nip width, then the nip width is increased, but the heat conductivity is reduced and warm-up time is extended
Solution Approach 1:
The patent changes the material parameters of the elastic layer by selecting silicone rubber with specific properties (elastic modulus of 10^6 to 10^7 dyne/cm², pressing rate of 30% to 70%) to achieve both wide nip width and adequate heat conductivity. This parameter optimization allows the elastic layer to be thick enough for wide nip width while maintaining sufficient thermal performance.
2Area of moving object
If the elastic layer of the elastic roller is thickened to widen the nip width, then the nip width is increased, but the power consumption at the heating section is increased
Solution Approach 1:
The patent optimizes the elastic layer parameters (material composition, thickness, elastic modulus) to achieve the desired nip width with minimum heat loss. By selecting silicone rubber with specific thermal conductivity and elastic properties, the system achieves wide nip width while minimizing the heating power required to maintain operating temperature.
3Reliability
If the elastic layer has high elasticity to improve followability, then the fixation properties are improved, but the peeling properties deteriorate
Solution Approach 1:
The patent precisely controls the elastic properties of the silicone rubber layer, specifying the elastic modulus (10^6 to 10^7 dyne/cm²) and pressing rate (30% to 70%). This parameter control ensures the elastic layer is soft enough to conform to toner images for good fixation, but not so soft that it causes poor peeling. The specific material selection balances these opposing requirements.
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 excellent fixation properties by uniformly heating toner images and extending the nip width, leading to improved peeling properties and energy efficiency in the image forming process.
Implementation Method 1
a heating roller for contacting with an inner circumferential surface of the endless fixing belt and heating the endless fixing belt
Implementation Method 2
the elastic layer on the surface of the elastic roller is elastically deformed corresponding to unevenness of an unfixed toner image
Data Source
AI summary
There are provided a fixing device having excellent fixation properties when a toner image is fixed onto a member to be subjected to fixation, and an image forming apparatus including the fixing device. A fixing device includes a fixing belt, a fixing roller and a heating roller between which the fixing belt is wound under tension, and a pressure roller which is in pressure-contact with the fixing roller through the fixing belt. An elastic layer as a surface layer of the fixing roller has, when being brought into pressure-contact with the pressure roller through the fixing belt, a pressing rate of 40% or more, and an Asker C hardness of 20 degrees or more and less than 30 degrees.