Fuser Unit Fixing Film With Folded Ends
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Solution Overview
Problem
In fuser units for electrographic image forming apparatuses, the transmission of driving force from the pressing roller to the fixing film is often insufficient, leading to slipping, which prevents firm fixation of the developer image on the recording sheet and can result in damage to the thin edges of the fixing film.
Innovation Solution
A fuser unit design featuring a cylindrical member with folded-back portions at its outer ends, forming steps that engage a backup member, which enhances the transmission of driving force and protects the film edges by positioning fragile parts away from open ends, thereby preventing slipping and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressing roller drives the fixing film to rotate, then the developer image can be fixed on the recording sheet, but the driving force may not be sufficiently transmitted to the fixing film, causing the fixing film to slip
Solution Approach 1:
The fixing film is segmented by forming folded-back portions at both ends, which creates distinct functional zones: the folded-back portions engage with the backup member to prevent slipping, while the central portion performs the fixation function. This segmentation allows the driving force to be effectively transmitted through the folded-back portions without compromising the fixation reliability of the main body.
Solution Approach 2:
The folded-back portions extend the fixing film in the radial direction (another dimension) to create steps that engage with the backup member. This dimensional change transforms the simple cylindrical surface into a multi-level structure, enabling mechanical interlocking that enhances driving force transmission while maintaining the fixation function.
2Object-affected harmful factors
If the fixing film is made thin to reduce damage to the recording sheet, then the film is more flexible, but the edge portions become easily damaged and may crack or break due to contact with surrounding components
Solution Approach 1:
The folded-back portions are formed in advance at both ends of the fixing film, creating a protective structure before the film undergoes operational stress. This preliminary structural modification ensures that the fragile edge portions are positioned away from open ends and potential damage zones, preventing cracking or breaking during operation while maintaining the thinness required to protect the recording sheet.
3Reliability
If the folded-back portions are formed by folding back entire circumferences of both ends outward, then steps are formed to suppress slipping, but the device structure becomes more complex
Solution Approach 1:
The folded-back portions are formed by folding the fixing film itself, utilizing the material's own structure to create the anti-slipping steps. This self-service approach eliminates the need for separate components or complex assembly mechanisms, as the fixing film's own geometry provides the slipping suppression function while maintaining relatively simple device structure.
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 design effectively suppresses slipping of the fixing film, ensuring reliable fixation of the developer image and preventing damage to the film edges, while maintaining the integrity of the film during operation.
Implementation Method 1
a halogen lamp which heats the nip plate and the fixing film
Implementation Method 2
a pressing roller which is disposed to press the fixing film; and a motor which drives the pressing roller
Data Source
AI summary
A fuser unit includes a cylindrical member that has flexibility; a nip member that is disposed to slidingly contact with an inner surface of the cylindrical member; and a backup member that is driven by a driving force and configures a nip region between the backup member and the cylindrical member on the nip member, wherein the cylindrical member includes folded-back portions formed at outer sides of a recording-sheet conveyance region in a recording-sheet width direction by folding back entire circumferences of both ends of the cylindrical member outward.