Fixing Apparatus Thermal Management Graphite Sheet
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Solution Overview
Problem
Image forming apparatuses face challenges in suppressing temperature increases at non-sheet-passing portions during the printing process, leading to potential thermal damage and reduced productivity, as existing solutions either prolong start-up times or fail to efficiently manage heat equalization.
Innovation Solution
A fixing apparatus is designed with a combination of a first thermally conductive metal plate and a second thermally conductive graphite sheet, where the graphite sheet has high in-plane thermal conductivity and low thickness-direction conductivity, positioned between the heating member and the supporting member, to effectively manage heat transfer and reduce temperature increases at non-sheet-passing portions while maintaining quick start-up times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of a metal plate thermally conductive member is increased to improve heat equalization performance, then the amount of heat transport increases, but the heat capacity increases proportionally, absorbing more heat at startup and prolonging the time required to raise temperature to fixing level
Solution Approach 1:
The patent combines a metal plate (first thermally conductive member) with a graphite sheet (second thermally conductive member) to create a composite thermal management structure. The metal plate provides high thermal conductivity in the thickness direction for rapid heat distribution, while the graphite sheet provides high in-plane thermal conductivity for lateral heat equalization. This composite approach allows optimized heat transport without the heat capacity penalty of a single thick metal plate.
Solution Approach 2:
The patent applies different thermal conductivity characteristics to different spatial directions and locations. The metal plate addresses vertical heat transport needs, while the graphite sheet addresses lateral heat equalization needs. This localized optimization of thermal properties allows the system to achieve comprehensive heat management without uniformly increasing heat capacity throughout the entire structure.
2Temperature
If a graphite sheet is used as the thermally conductive member, then heat equalization in the longitudinal direction is improved, but the thermal conductivity in the thickness direction is low, limiting the amount of heat transport
Solution Approach 1:
The patent creates a composite structure where the graphite sheet's high in-plane thermal conductivity complements the metal plate's high thickness-direction thermal conductivity. This combination allows the system to overcome the limitation of low thickness-direction conductivity in graphite while preserving its excellent lateral heat equalization capabilities.
Solution Approach 2:
The metal plate acts as an intermediary that bridges the thermal conductivity gap in the thickness direction. It receives heat from the heating member and distributes it laterally, while also providing a thermal pathway that connects to the graphite sheet, enabling efficient heat transport without relying solely on the graphite sheet's limited thickness-direction conductivity.
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 temperature increases at non-sheet-passing portions and reduces start-up times by leveraging the anisotropic thermal conductivity of the graphite sheet, enhancing heat equalization and maintaining efficient operation.
Implementation Method 1
a heating member including a substrate and a heating resistor formed on the substrate
Implementation Method 2
The second thermally conductive member has a thermal conductivity in in-plane directions and a thermal conductivity in a thickness direction, and the thermal conductivity in the in-plane directions is higher than the thermal conductivity in the thickness direction
Data Source
AI summary
A fixing apparatus includes a heating member, a supporting member that supports the heating member, a film slidably disposed on the heating member, and a pressing member that forms a nip portion, in collaboration with the film, through which the recording medium is conveyed. The fixing apparatus further includes a first thermally conductive member and a second thermally conductive member that are disposed between the heating member and the supporting member. The first thermally conductive member has a thermal conductivity higher than that of a substrate of the heating member. The thermal conductivity in in-plane directions of the second thermally conductive member is higher than the thermal conductivity in a thickness direction thereof. The second thermally conductive member is in contact with the heating member, and the first thermally conductive member is in contact with the second thermally conductive member.