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 efficiently heating and maintaining consistent temperature across the fixing belt, leading to uneven toner fixation and potential damage to subsequent prints due to residual toner from previous sheets.
Innovation Solution
The implementation of a fixing device with a flexible endless belt, a pressure rotator, and a combination of radiant heaters and contact heaters, where the thermal conduction aid covers the nip formation pad and contact heaters to ensure uniform heat distribution and prevent overheating at lateral ends, along with a stay that screens the radiant heaters to enhance heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If radiant heaters are used to heat the fixing belt, then heating efficiency is improved, but uneven temperature distribution occurs across the belt width
Solution Approach 1:
The patent applies contact heaters specifically at the lateral ends of the fixing belt where temperature deficiency occurs, while radiant heaters cover the central region. This local differentiation of heating methods ensures each zone receives appropriate heat treatment, resolving the uniformity issue while maintaining overall heating efficiency.
Solution Approach 2:
The patent combines two different heating methods (radiant heating and contact heating) into a unified heating system. The radiant heaters provide efficient bulk heating while contact heaters supplement the lateral end regions, creating a complementary heating arrangement that achieves both efficiency and uniformity.
2Temperature
If the fixing belt has high thermal capacity to maintain temperature, then temperature stability is improved, but overheating at lateral ends occurs
Solution Approach 1:
The thermal conduction aid is applied specifically at the lateral ends of the fixing belt where overheating occurs, creating a local heat dissipation pathway. This allows the central region to maintain its thermal capacity for stability while the lateral ends have enhanced heat removal capability to prevent damage.
Solution Approach 2:
The thermal conduction aid acts as an intermediary substance between the fixing belt and the lateral end structure. It facilitates controlled heat transfer from the overheating lateral regions to cooler areas, mediating the temperature distribution without requiring fundamental changes to the belt's thermal properties.
3Device complexity
If a single heater configuration is used, then device complexity is reduced, but heating uniformity across different sheet sizes cannot be achieved
Solution Approach 1:
The heating system is segmented into distinct functional zones: radiant heaters for the central region and contact heaters for the lateral ends. This segmentation allows independent optimization of each zone's heating characteristics, enabling the system to adapt to various sheet sizes and positions while maintaining manageable complexity through modular design.
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 and efficient toner fixation on various sheet sizes, prevents residual toner from affecting subsequent prints, and maintains the quality of the toner image by ensuring uniform heating and reduced thermal capacity of the fixing belt.
Implementation Method 1
A first radiant heater is disposed inside the loop formed by the endless belt. The first radiant heater includes a first heat generator to heat the endless belt. A second radiant heater is disposed inside the loop formed by the endless belt. The second radiant heater includes a second heat generator, disposed outboard from the first heat generator in an axial direction of the endless belt, to heat the endless belt.
Implementation Method 2
A contact heater, disposed at least at one lateral end of the nip formation pad in a longitudinal direction of the nip formation pad, heats at least one lateral end of the endless belt in the axial direction of the endless belt.
Implementation Method 3
A thermal conduction aid, covering the nip-side face of the nip formation pad and the nip-side face of the contact heater, conducts heat applied to the endless belt in the axial direction of the endless belt.
Data Source
AI summary
A fixing device includes an endless belt, a first radiant heater including a first heat generator to heat the endless belt, and a second radiant heater including a second heat generator, disposed outboard from the first heat generator in an axial direction of the endless belt, to heat the endless belt. A nip formation pad includes a nip-side face disposed opposite the endless belt. A contact heater heats at least one lateral end of the endless belt in the axial direction of the endless belt. The contact heater includes a nip-side face disposed opposite the endless belt. A thermal conduction aid covers the nip-side face of the nip formation pad and the nip-side face of the contact heater and conducts heat applied to the endless belt in the axial direction of the endless belt.