Fixing Apparatus Guide Member Asymmetry for Gloss Uniformity
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Solution Overview
Problem
Existing film heating type fixing apparatuses face challenges in maintaining uniform glossiness of toner images across the printing material, as the holder tends to deflect more at the center than at the ends, leading to uneven glossiness and impaired image quality.
Innovation Solution
The design includes a guide member and a stay that reduce deflection in the printing-material conveying direction by positioning the holder's contact surfaces downstream from the ends, ensuring uniform pressure distribution and glossiness through precise alignment of the holder and pressure stay components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the holder is pressed by a metal pressure stay to apply pressure to the pressure roller, then the rigidity and pressure application are improved, but the deflection at the center increases causing non-uniform glossiness
Solution Approach 1:
The contact surface of the guide member is positioned downstream at the center portion but not at the end portions in the printing-material conveying direction. This creates different positional relationships between the guide member and pressure stay at different locations, allowing the center to have restricted deflection while ends maintain natural positioning, achieving uniform glossiness across the width of the printing material
Solution Approach 2:
The guide member's contact surface is segmented into different regions: the center portion contacts the pressure stay downstream, while the end portions do not contact or contact at different positions. This segmentation allows different parts of the holder to have different deflection characteristics, preventing excessive center deflection while maintaining overall structural integrity
2Ease of operation
If the holder receives force from the film in the printing-material conveying direction, then the film guidance is improved, but the displacement amount increases toward the center causing insufficient protruding portion effect
Solution Approach 1:
The guide member is positioned to contact the pressure stay upstream or at different positions compared to the holder's protruding portion, creating a counterbalancing effect that prevents excessive downstream displacement of the holder center. This preliminary positioning restriction counteracts the force from the rotating film before it causes excessive deflection
3Stability of the object's composition
If both ends of the pressure stay and holder are supported by flanges, then the structural stability is improved, but the deflection at the center increases relative to the ends
Solution Approach 1:
The guide member is positioned asymmetrically relative to the pressure stay, with the contact surface at the center located downstream from the end portions. This asymmetric arrangement creates different mechanical constraints at different locations, allowing the center to have reduced deflection while maintaining overall structural stability provided by the flange-supported ends
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 achieves highly uniform glossiness across the toner image, reducing deflection and maintaining consistent pressure peaks at both ends and the center, thereby enhancing image quality and user satisfaction.
Implementation Method 1
A printing material that carries an unfixed toner image is heated while being nipped and conveyed through the nip portion, so that the toner image is fixed onto the printing material
Implementation Method 2
a pressure roller that forms a nip portion with the heater, with the film therebetween, and a pressure stay that presses the holder against the pressure roller
Data Source
AI summary
A fixing apparatus includes a guide member that guides a rotating member. The guide member has a contact surface that restricts a position of the guide member with respect to a stay by coming into contact with a surface of the stay on the upstream side in a printing-material conveying direction. The contact surface is disposed, in a direction perpendicular to the printing-material conveying direction, in such a manner that a center is downstream from ends in the printing-material conveying direction.