Fixing Device Thermally Conductive Member Segmentation
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Solution Overview
Problem
In image forming apparatuses, the film fixing method leads to non-sheet-passing-portion temperature rise, causing thermal stress and potential deformation of thermally conductive members, resulting in local temperature rises and defective images due to gaps between thermally conductive members.
Innovation Solution
A fixing device with a cylindrical film, a support member, and thermally conductive members arranged to engage with each other, reducing the gap width and preventing deformation by ensuring thermal conductivity is higher than the support member, thus maintaining uniform temperature distribution and preventing local temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple thermally conductive members are arranged in the longitudinal direction to prevent deformation due to heat cycle, then deformation of thermally conductive members is prevented, but local temperature rise occurs at the gap between members causing defective images
Solution Approach 1:
The thermally conductive member is divided into multiple segments arranged in the longitudinal direction. Each segment is independently supported by the heater support member, allowing thermal expansion without deformation while maintaining overall thermal conductivity. The segmented structure prevents stress concentration that would occur in a single continuous member.
Solution Approach 2:
The gap between thermally conductive members is strategically positioned to avoid critical heating zones. By controlling the location and dimensions of gaps, the design allows thermal expansion space while minimizing impact on temperature uniformity in areas where heat application is most critical.
2Temperature
If the gap between thermally conductive members is minimized to improve temperature uniformity, then temperature leveling effect is improved, but thermally conductive members may contact and deform due to thermal expansion
Solution Approach 1:
The heater support member is designed with predetermined support positions and spacing that anticipate thermal expansion. The support structure is configured before assembly to provide appropriate clearance and guidance, preventing contact between members during thermal cycles while maintaining minimal gap for temperature uniformity.
Solution Approach 2:
The dimensions, spacing, and material properties of thermally conductive members are optimized to balance thermal conductivity with thermal expansion characteristics. By adjusting parameters such as member thickness, gap width, and support positioning, the design achieves both temperature uniformity and prevention of deformation.
3Temperature
If a single continuous thermally conductive member is used to maximize temperature leveling effect, then temperature distribution is improved, but the member deforms due to thermal stress from repeated heating and cooling
Solution Approach 1:
The continuous thermally conductive member is divided into multiple segments that are arranged end-to-end in the longitudinal direction. Each segment is independently supported by the heater support member, allowing the structure to accommodate thermal expansion and contraction without generating excessive stress that would cause deformation.
Solution Approach 2:
The heater support member acts as an intermediary structure that provides support and positioning for the thermally conductive members. It includes features such as recesses, protrusions, or engagement structures that maintain proper spacing and alignment while allowing thermal movement, thus preventing direct contact and deformation between members.
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 suppresses local temperature rises and prevents deformation of thermally conductive members, ensuring consistent image quality by maintaining uniform temperature distribution across the heating member.
Implementation Method 1
A first thermally conductive member and a second thermally conductive member are provided between the heating member and the support member... each of the first thermally conductive member and the second thermally conductive member having thermal conductivity higher than thermal conductivity of the support member
Implementation Method 2
the thermally conductive member can be deformed due to a difference between a thermal expansion amount (thermal expansion rate) of the heater and that of the thermally conductive member in a case the thermally conductive member between the heater and the heater support member are provided
Data Source
AI summary
A fixing device includes a cylindrical film, a support member disposed on an inner peripheral surface of the film, a heating member supported by the support member and provided slidably with the film, and a pressing member that forms a pressure contact portion together with the heating member through the film. The fixing device heats a recording medium while pressing the recording medium at the pressure contact portion. A first thermally conductive member and a second thermally conductive member are provided between the heating member and the support member. The first and second thermally conductive members having thermal conductivity higher than that of the support member are configured to engage with each other.