Fixing Device Movable Shielding Members Heat Management
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face issues with heat accumulation and deformation of shielding members due to excessive heat, leading to degradation and interference with other components, especially during continuous high-speed printing.
Innovation Solution
A fixing device with an endless moving member, a pressure member, a nip-forming member, and a heat source, featuring movable shielding members that adjust between shielding and retracted positions to prevent excessive heat absorption in non-sheet passing areas, controlled by a circuit to maintain optimal temperatures and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shielding members are disposed between the heat source and the fixing belt to prevent excess temperature rise, then the degradation of the fixing belt is prevented, but the shielding members themselves get overheated and deformed
Solution Approach 1:
The shielding function is divided into multiple independent shielding members (first shielding member and second shielding member) positioned at different locations between the heat source and the fixing belt. This segmentation allows heat to be blocked at multiple points, reducing the temperature load on each individual shielding member while maintaining effective protection of the fixing belt.
Solution Approach 2:
The shielding members act as intermediary elements between the heat source and the fixing belt. These intermediaries absorb and block radiant heat, preventing direct heating of the fixing belt in non-sheet passing areas. The shielding members are specifically designed to intercept heat rays before they reach the fixing belt, thereby protecting the fixing belt from overheating while the segmented structure prevents excessive temperature accumulation in any single shielding member.
2Use of energy by moving object
If radiant heat is used to heat the fixing belt directly, then heating efficiency is improved and energy consumption is reduced, but heat accumulates in non-sheet passing areas causing degradation
Solution Approach 1:
The shielding members are strategically positioned to provide localized heat blocking only in the non-sheet passing areas of the fixing belt. This local quality approach allows the fixing belt to receive radiant heat in sheet passing areas for efficient heating, while simultaneously protecting non-sheet passing areas from heat accumulation. The shielding members create a spatially differentiated heat distribution, enabling efficient heating where needed and protection where not needed.
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 solution effectively prevents deformation of shielding members and maintains the functionality of the fixing device by managing heat distribution, ensuring efficient and reliable image formation across various sheet sizes.
Implementation Method 1
a heat source to heat the fixing belt with radiant heat is disposed at an interior side of the fixing belt
Implementation Method 2
a shielding member that shields radiant heat from the heat source, disposed between the heat source and the fixing belt
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fixing device (100) includes an endless moving member (121); a pressure member (122) to contact an outer circumferential surface of the endless moving member (121); a nip forming member (24) disposed at an interior side of the moving member and contacting the moving member (121) against the pressure member (122) to form a nip portion; a heat source (23) disposed at an interior side of the moving member to heat the moving member with radiant heat; plural shielding members (29) disposed between the heat source (23) and the moving member (121) and movable between a shielding position where the plural shielding members (29) shield a non-sheet passing area on the moving member (121) from the radiant heat from the heat source (23) and a retracted position; and a control circuit to move each of the plural shielding members (29) between the shielding position and the retracted position.