Fixing Device Belt Heating and Protection
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Solution Overview
Problem
Existing fixing devices face challenges in reducing warm-up time, first-print time, and heat shortage during high-speed image forming, particularly with belt fixing methods, and SURF methods that fail to uniformly heat the belt, leading to fixing failures.
Innovation Solution
A novel fixing device with a rotatable endless fixing rotary member, a heating source, an opposite rotary member, a nip forming member, holding members, and protecting members, where the fixing rotary member is directly heated by the heating source, and the protecting members have an inclined surface with a low coefficient of friction to prevent belt damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the belt fixing method is used to reduce device size and heat capacity, then warm-up time and first-print time are reduced, but temperature drop occurs during continuous printing due to insufficient heat capacity
Solution Approach 1:
The patent applies local quality by providing heating sources at multiple locations along the belt - specifically at both ends of the belt in addition to the center. This creates non-uniform heating distribution that compensates for heat loss during continuous rotation, ensuring temperature stability throughout the entire belt while maintaining compact device size.
2Loss of time
If the SURF method is used to locally heat the nip portion, then warm-up time is reduced, but the remaining portion of the belt remains cool causing fixing failures
Solution Approach 1:
The patent segments the heating function by providing multiple independent heating sources positioned at different locations along the belt (center and both ends). This segmentation allows simultaneous heating of different belt regions, ensuring the nip portion is quickly heated while also maintaining temperature in the remaining belt portions during continuous operation.
Solution Approach 2:
The patent applies local quality by providing heating sources at multiple locations along the belt - specifically at both ends of the belt in addition to the center. This creates non-uniform heating distribution that compensates for heat loss during continuous rotation, ensuring temperature stability throughout the entire belt while maintaining compact device size.
3Productivity
If the belt rotation speed is increased for high-speed printing, then processing speed is improved, but heat discharge from the belt increases causing temperature drop
Solution Approach 1:
The patent applies preliminary action by pre-heating the entire belt through multiple heating sources before the belt enters the nip portion. This ensures that even at high rotation speeds, the belt maintains sufficient temperature throughout its path, compensating for the increased heat discharge caused by faster rotation.
4Strength
If the end portions of the fixing rotary member are directly contacted by holding members, then the fixing rotary member is securely held, but the end portions are damaged due to friction and stress
Solution Approach 1:
The patent introduces an intermediary element (the protecting member or guide member) between the holding member and the end portion of the fixing rotary member. This intermediary reduces direct friction and stress concentration on the belt end, while still providing secure positioning through the inclined surface that guides the belt onto the rotating member.
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 reduces warm-up time and first-print time, enhances heat transfer efficiency, and minimizes belt damage, improving the overall fixing performance and energy conservation.
Implementation Method 1
a heating source 300, and a pressure roller 400. The pressure roller 400 is in contact with the metal heat conductor 200 via the endless belt 100 to form a nip portion N. The endless belt 100 is rotated by the rotation of the pressure roller 400. In this process, the metal heat conductor 200 guides the movement of the endless belt 100. Further, the endless belt 100 is heated, via the metal heat conductor 200, by the heat source 300 inside the metal heat conductor 200.
Implementation Method 2
the endless belt 100 is heated, via the metal heat conductor 200, by the heat source 300 inside the metal heat conductor 200
Implementation Method 3
Each of the protecting members has an opposite surface which faces the corresponding one of the end surfaces of the fixing rotary member, and which includes an inner diameter-side end edge provided with an inclined surface inclined in an inner diameter direction and away from the fixing rotary member.
Data Source
AI summary
A fixing device for fixing an image on a recording medium includes a rotatable endless fixing rotary member, a heating source which heats the fixing rotary member, an opposite rotary member in contact with the fixing rotary member, a nip forming member provided inside the fixing rotary member and in contact with the opposite rotary member via the fixing rotary member to form a nip portion to which the recording medium is fed, holding members rotatably holding end portions of the fixing rotary member, and protecting members provided between the holding members and end surfaces of the fixing rotary member to protect the end portions. Each of the protecting members has an opposite surface facing the corresponding end surface of the fixing rotary member, and including an inner diameter-side end edge having an inclined surface inclined in an inner diameter direction and away from the fixing rotary member.