Fixing Roller Curvature for Sheet Curl Control
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Solution Overview
Problem
Conventional image forming apparatuses face issues with sheet curling due to uneven contact time with heating rollers, leading to unstable fixing properties and non-uniform image glossiness, which can cause jamming and stacking failures.
Innovation Solution
The apparatus incorporates a tandem-type image forming structure with a fixing device featuring a heating roller and a pressuring roller, where the pressuring roller is biased by an elastic member to form an arc-shaped nip, and a pair of conveying rollers with a separation supporting mechanism to stabilize sheet conveyance, ensuring consistent contact time and reducing curling by adjusting conveying speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sheet is conveyed quickly after fixing to counteract curl, then curl is reduced, but contact time with heating roller becomes unstable and fixing property deteriorates
Solution Approach 1:
The patent applies curvature to the conveying path by introducing a curved guide member that directs the sheet through an arc-shaped trajectory. This curved conveyance path allows the sheet to be guided smoothly while maintaining stable contact with the heating roller, preventing curl without requiring rapid conveyance that would compromise fixing quality.
Solution Approach 2:
The patent introduces a curved guide member as an intermediary element between the fixing unit and the ejecting roller. This guide member mediates the sheet's transition by providing a controlled curved path, allowing the sheet to be redirected to counteract curl while maintaining stable contact time with the heating roller during the fixing process.
2Device complexity
If conventional conveying mechanism is used, then device complexity is low, but dispersion of contact time occurs and fixing property becomes unstable
Solution Approach 1:
The curved guide member serves as an intermediary component that is relatively simple in structure but effectively stabilizes the sheet's contact time with the heating roller. This intermediary element provides a controlled curved path without requiring complex mechanisms, thus maintaining low device complexity while improving fixing reliability.
3Object-affected harmful factors
If sheet is conveyed through curved path, then curl is restrained, but jamming may occur if curvature is excessive
Solution Approach 1:
The patent applies a moderate arc-shaped curvature to the guide member that is sufficient to counteract sheet curl but not so excessive as to cause jamming. The curved path is designed with an optimized radius that balances curl restraint with smooth sheet flow, preventing both curl and jamming simultaneously.
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 stabilizes the fixing process, prevents curling, and ensures uniform image formation by maintaining consistent contact time and reducing the likelihood of jamming and stacking failures.
Implementation Method 1
a pressuring roller, and an elastic member for biasing the pressuring roller
Implementation Method 2
heats and melts a toner of a toner image formed on a sheet... and fixes an image onto the sheet by further heating
Implementation Method 3
heats and melts a toner of a toner image formed on a sheet
Implementation Method 4
heats and melts a toner... by further heating
Implementation Method 5
a first conveying part comprising a pair of conveying rollers, and a second conveying part comprising a pair of ejecting rollers
Data Source
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AI summary
An image forming apparatus (10) includes a fixing part (26), a first conveying part (35), a second conveying part (37), a biasing member (64) and a separation supporting mechanism (62). The first conveying part (35) following the fixing part (26) includes rollers (35A, 35B) to convey a sheet at second linear velocity (V2) faster than first linear velocity (V1) of the fixing part (26). The second conveying part (37) following the first conveying part (35) conveys the sheet at third linear velocity (V3) faster than the first linear velocity (V1) near a heating rotation body (26A) of the fixing part (26) from a first reference line (L5) passing through nip parts (26C, 35C) of the fixing part (26) and first conveying part (35). The separation supporting mechanism (62) supports one roller (35A) in a direction separating from another roller (35B) and receives force from the sheet in the separating direction to the one roller (35A) when the second conveying part (37) conveys the sheet to withdraw the one roller (35A) in the separating direction from the first reference line (L5).