Pressure Roller Rubber Layer Thermal Expansion Control
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Solution Overview
Problem
In image forming apparatuses, pressure rollers with low thermal conduction in the rubber layer cause excessive temperature rise in sheet non-passing portions, especially when handling small recording materials, leading to issues with conveying velocity adjustments and potential image distortion due to thermal expansion.
Innovation Solution
A pressure roller with a rubber layer containing void portions, pore passage portions, and a filler, where the aspect ratio of the filler is 2.5≤RA≤215, and a linear expansion coefficient of the rubber layer is less than or equal to 400×10−6/K, to reduce thermal expansion and maintain quick start properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a rubber layer with many void portions is used to achieve low thermal conduction and quick start property, then the warming up time is shortened, but the temperature rise in sheet non-passing portion becomes excessive
Solution Approach 1:
The rubber layer is designed with a porous structure containing many void portions to reduce thermal conduction and enable quick warming up. This porous structure allows the rubber layer to heat up rapidly while maintaining low thermal conduction to prevent excessive temperature rise in sheet non-passing portions.
Solution Approach 2:
The rubber layer is composed of a composite material system including rubber base resin, void portions, and pore passage portions. This composite structure combines the benefits of rapid heating with thermal insulation properties to resolve the contradiction between quick start and temperature control.
2Device complexity
If the conveying path is shortened and the same motor is used for both transfer unit and fixing unit, then the apparatus is downsized and simplified, but the conveying velocity cannot be individually adjusted causing image extension
Solution Approach 1:
The patent changes the physical parameters of the rubber layer, specifically controlling the linear expansion coefficient to be 400×10−6/K or less. This parameter change allows the rubber layer to minimize thermal expansion, thereby maintaining stable conveying velocity and preventing image extension even when the same motor is used for both units.
3Stability of the object's composition
If the linear expansion coefficient of the rubber layer is reduced to prevent conveying velocity changes, then image distortion is prevented, but the thermal conduction properties may be affected
Solution Approach 1:
The patent applies local quality by creating specific regions within the rubber layer with different properties. The rubber layer has void portions and pore passage portions strategically distributed to achieve both low linear expansion coefficient (for stable conveying velocity) and appropriate thermal conduction (for efficient energy transmission).
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 effectively reduces thermal expansion and temperature rise in sheet non-passing portions, allowing for stable conveying velocities and preventing image distortion, while maintaining quick start capabilities and reducing the risk of temperature-related issues.
Implementation Method 1
The rubber layer thermally expands by heating when printing is performed. The degree of heating differs depending on various printing conditions, and therefore, the amount of expansion of the rubber layer also changes in various ways.
Implementation Method 2
a plate-like heater is placed in an inner space of a cylindrical fixing film, and a fixing nip portion is formed by the heater and a pressure roller via the fixing film
Implementation Method 3
For the purpose of efficiently transmitting thermal energy from a heating unit to a recording material and toner
Data Source
AI summary
A roller used in a fixing device includes a rubber layer including a plurality of void portions, pore passage portions connecting the void portions, and a filler, wherein an aspect ratio RA of the filler is 2.5≤RA≤215, and a linear expansion coefficient of the rubber layer is less than or equal to 400×10−6/K.