Fixing Device Thermal Conduction Aid for Uniform Belt Heating
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in uniformly heating and maintaining the temperature of the fixing belt, leading to uneven toner image fixation, especially for larger sheets, due to variations in heat output from halogen heaters and lateral end heaters.
Innovation Solution
The implementation of a flexible endless belt with a nip formation pad, radiant heaters, and a thermal conduction aid that covers both the nip formation pad and lateral end heaters, ensuring uniform heat distribution and temperature equalization along the belt, while the contact heaters and power supply are positioned to prevent overheating and contact with the belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If halogen heaters and lateral end heaters are used to heat the fixing belt, then the fixing temperature can be maintained, but uneven heat output leads to non-uniform temperature distribution across the belt
Solution Approach 1:
The fixing device employs different heating methods for different regions of the fixing belt: radiant heaters (halogen heaters) for the central region and contact heaters (lateral end heaters) for the lateral end regions. This local differentiation addresses the varying heat requirements across the belt width, ensuring uniform temperature distribution by applying appropriate heating strategies to specific zones.
Solution Approach 2:
A thermal conduction aid is introduced as an intermediary component between the contact heaters and the fixing belt. This thermal conduction aid receives heat from the contact heaters and uniformly distributes it to the lateral end regions of the fixing belt, acting as a mediator that transforms the localized heat output into uniform thermal distribution across the belt surface.
2Use of energy by moving object
If contact heaters are positioned close to the fixing belt for efficient heat transfer, then heating effectiveness improves, but risk of overheating and direct contact increases
Solution Approach 1:
The thermal conduction aid serves as a protective intermediary layer positioned between the contact heaters and the fixing belt. It maintains close proximity for efficient heat transfer while preventing direct contact and overheating. The thermal conduction aid absorbs and distributes the heat uniformly, eliminating the harmful effects of concentrated thermal energy while preserving the benefits of efficient heat transfer.
Solution Approach 2:
The heating system applies different thermal management strategies to different regions: the central region uses radiant heaters that naturally distribute heat over a broader area, while the lateral end regions use contact heaters with thermal conduction aids specifically designed to manage heat locally and prevent overheating at the edges.
3Adaptability or versatility
If the fixing belt is made flexible for better conformability, then it can adapt to different sheet sizes, but temperature control becomes more challenging
Solution Approach 1:
The heating system is segmented into multiple independent heating zones with different heating mechanisms: radiant heaters for the central region and contact heaters with thermal conduction aids for the lateral end regions. This segmentation allows each zone to be controlled independently, compensating for temperature variations that occur when the flexible belt conforms to different sheet sizes and maintaining uniform temperature across the entire belt surface.
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 ensures consistent heat output and temperature control across the fixing belt, effectively fixing toner images on sheets of varying sizes without degradation, enhancing the reliability and efficiency of the image forming process.
Implementation Method 1
A thermal conduction aid contacts the belt-side face of the nip formation pad and the belt-side face of the contact heater and conducts heat in the axial direction of the endless belt
Implementation Method 2
At least one radiant heater is disposed opposite the inner circumferential surface of the endless belt to heat the endless belt
Implementation Method 3
A contact heater is disposed at least at one lateral end of the nip formation pad in a longitudinal direction of the nip formation pad and heats at least one lateral end of the endless belt in an axial direction of the endless belt
Data Source
AI summary
A fixing device includes a nip formation pad which is disposed opposite an endless belt and forms a fixing nip between the endless belt and a pressure rotator. A contact heater is disposed at least at one lateral end of the nip formation pad in a longitudinal direction thereof and heats at least one lateral end of the endless belt in an axial direction thereof. A thermal conduction aid contacts a belt-side face of each of the nip formation pad and the contact heater and conducts heat in the axial direction of the endless belt. A cover is disposed outboard from the thermal conduction aid in a longitudinal direction thereof. The cover covers the belt-side face of the contact heater. The contact heater includes a power supply portion disposed outboard from the thermal conduction aid in the longitudinal direction thereof and covered by the cover.