Asymmetric Fixing Device Structure for Axial Heat Uniformity
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Solution Overview
Problem
Existing image forming apparatuses using electrophotographic processes face issues with temperature deviations in the fixing device due to asymmetrical exposure of the rotation shaft, leading to uneven heat distribution and potential fixability defects, without increasing device size or cost.
Innovation Solution
The apparatus includes a frame body with asymmetrically designed openings to balance heat distribution by varying the length of the rotation shaft exposure and opening areas on either side, preventing temperature deviations in the rotational axis direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotation shaft is exposed equally on both ends of the pressing roller, then the structure is symmetric and simple, but temperature deviation occurs in the rotational axis direction due to heat transfer toward the ends
Solution Approach 1:
The pressing roller is designed with asymmetric exposure of the rotation shaft, where one end is exposed longer than the other end. This asymmetric structure compensates for the heat transfer effect toward the ends, balancing the temperature distribution in the rotational axis direction and preventing temperature deviation in the fixing device.
2Temperature
If multiple heating bodies are added to independently generate heat and balance temperature, then temperature uniformity is improved, but device size and cost increase
Solution Approach 1:
Instead of adding multiple heating bodies, the invention adjusts the local structure of the pressing roller by asymmetrically exposing the rotation shaft at different lengths on each end. This local structural modification changes the heat transfer characteristics to achieve temperature uniformity without increasing device size or adding complex heating components.
3Temperature
If a cooling fan is added to blow air partially to balance temperature, then temperature uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The invention enables the pressing roller to self-regulate its temperature distribution through its asymmetric structure. The asymmetric exposure of the rotation shaft naturally balances heat transfer without requiring external cooling fans or active temperature control systems, reducing device complexity while achieving temperature uniformity.
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 inhibits temperature deviations in the fixing device while maintaining device size and cost, ensuring uniform heat distribution and preventing fixability defects.
Implementation Method 1
a heater disposed in an internal space of the first rotation body
Implementation Method 2
heat is transferred toward an end of the rotation shaft
Implementation Method 3
a total area of openings disposed in a first region of the frame body is a first value, and a total area of openings disposed in a second region of the frame body is a second value larger than the first value
Data Source
AI summary
An image forming apparatus includes: a first and second rotation bodies; a heater disposed in the first rotation body; and a frame body supporting the first and second rotation bodies. A second length is smaller than a first length in a rotational axis direction of the second rotation body, the first length and the second length being a length of a rotation shaft of the second rotation body exposed on a one-end side and an other-end side of the second rotation body, and a second value is larger than a first value, the first value and the second value being a total area of openings disposed in a first region and a second region of the frame body respectively corresponding to the one-end side and the other-end side of the frame body with respect to a center of the frame body.