Fuser Guide Member Contact Layout for Uniform Film Heating
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Solution Overview
Problem
Existing fixing devices in image forming devices suffer from unevenness in fixed images due to temperature variations, which affect the quality of printed output.
Innovation Solution
A fixing device with a guide member featuring a plurality of contact portions, including first and second ribs with varying effective heat transfer coefficients, is employed to uniformly distribute heat across the tubular film, thereby reducing temperature and image unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional fixing device with uniform heat distribution is used, then the structure is simple, but temperature unevenness occurs causing image quality degradation
Solution Approach 1:
The guide member is segmented into multiple contact portions (first contact portion, second contact portion, third contact portion) along its longitudinal direction. Each contact portion has different heat transfer characteristics to address temperature unevenness at different positions, transforming a uniform structure into a differentiated segmented structure that actively manages thermal distribution.
Solution Approach 2:
Different contact portions of the guide member are designed with different effective heat transfer coefficients tailored to local thermal requirements. The first contact portion (near heater unit) has higher heat transfer coefficient, while the second contact portion (farther from heater unit) has lower coefficient, creating local quality variations that compensate for temperature gradients along the tubular film.
2Loss of energy
If the guide member has high heat transfer coefficient throughout, then heat transfer efficiency is high, but temperature unevenness increases causing image defects
Solution Approach 1:
The guide member implements local quality by varying the effective heat transfer coefficient of different contact portions. The first contact portion has higher heat transfer efficiency to capture heat from the heater unit, while the second contact portion has lower efficiency to prevent excessive heat extraction that would cause temperature drops and image defects. This localized differentiation resolves the contradiction between overall heat transfer efficiency and local temperature uniformity.
Solution Approach 2:
The design converts the potential harm of excessive heat transfer (which would cause temperature drops and image defects) into a benefit by strategically placing lower heat transfer coefficient contact portions at specific locations. This transforms what would be a uniform harmful effect into a controlled beneficial distribution pattern that maintains temperature uniformity.
3Temperature
If contact portions are uniformly distributed, then structural symmetry is maintained, but temperature unevenness cannot be effectively reduced
Solution Approach 1:
The guide member employs asymmetric distribution of contact portions along its longitudinal direction. The first contact portion is positioned near the heater unit with higher heat transfer coefficient, while the second contact portion is positioned farther away with lower heat transfer coefficient. This asymmetric arrangement breaks the symmetry to actively compensate for the natural temperature gradient that exists in the system, thereby achieving temperature uniformity.
Solution Approach 2:
Different contact portions are designed with different heat transfer characteristics according to local thermal conditions. The first contact portion (near heater unit) has higher effective heat transfer coefficient to efficiently capture heat, while the second contact portion (farther from heater unit) has lower coefficient to prevent over-cooling. This local quality differentiation enables temperature uniformity without requiring symmetric distribution.
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 temperature unevenness and improves image quality by ensuring uniform heat transfer along the longitudinal direction of the tubular film, resulting in enhanced print quality.
Implementation Method 1
The contact portions are configured to contact the inner surface of the tubular body. A first contact portion of the plurality of contact portions is located in an end portion of the guide member in the longitudinal direction. A second contact portion of the plurality of contact portions is located in a central portion of the guide member in the longitudinal direction. The second contact portion has an effective heat transfer coefficient with respect to the tubular body that is less than an effective heat transfer coefficient of the first contact portion with respect to the tubular body.
Data Source
AI summary
According to one embodiment, a fixing device includes a tubular body, a heater unit, a frame, and a guide member. The heater unit is inside the tubular body and contacts the tubular body. The frame supports the heater unit. The guide member is on a side opposite the heater unit with the frame therebetween. The guide member includes a plurality of contact portions which are spaced from each other in a longitudinal direction that parallels an axial direction of the tubular body. A first contact portion is located in an end portion of the guide member. The second contact portion is located in a central portion of the guide member. The second contact portion has an effective heat transfer coefficient with respect to the tubular body that is less than that of the first contact portion with respect to the tubular body.