Fusing Roller Crown and Pressing Member Convex-Concave Structure
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Solution Overview
Problem
Existing image forming apparatuses face issues with recording sheets becoming attached to fusing rollers due to toner adhesion and curling, which affects transportation and stacking, and the installation of separating units increases apparatus size and cost.
Innovation Solution
A fusing apparatus with a fusing roller and pressing belt that includes positive and negative crown portions on the roller and convex/concave surface portions on the pressing member, providing a varying pressing force distribution to prevent sheet attachment and curling without the need for additional separating units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separating nail or separating roller is installed to prevent sheet attachment and curling, then sheet separation reliability is improved, but apparatus size and cost increase
Solution Approach 1:
The pressing member is designed with localized convex and concave portions that create variable pressing forces at specific locations within the fusing nip. This local variation in pressing force prevents sheet attachment and curling without requiring separate dedicated separating components, thereby resolving the contradiction between separation reliability and device complexity
Solution Approach 2:
The pressing member serves dual functions: it applies necessary pressing force for toner fusion while simultaneously preventing sheet attachment and curling through its convex-concave surface structure. This multi-functionality eliminates the need for separate separating units, reducing apparatus size and cost while maintaining separation reliability
2Ease of manufacture
If uniform pressing force is applied across the fusing roller, then manufacturing simplicity is improved, but sheet curling and attachment occur
Solution Approach 1:
The pressing member incorporates convex and concave portions that create localized variations in pressing force. The convex portions apply higher pressing force to prevent sheet attachment, while concave portions allow controlled separation. This local quality variation resolves the contradiction by preventing sheet curling and attachment while maintaining manufacturing simplicity through a single integrated pressing member design
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
The solution effectively prevents sheet attachment and curling, ensuring proper separation and reducing apparatus size and cost by maintaining a consistent fusing nip width and preventing wrinkles, thus enhancing the reliability of the image forming process.
Implementation Method 1
a heating unit configured to heat the fusing roller
Implementation Method 2
The recording sheet is heated and pressed in the fusing nip so that the toner carried on the recording sheet can be heated and melted
Implementation Method 3
a biasing unit configured to apply a biasing force to the pressing member in order to press the pressing member onto the internal peripheral surface of the pressing belt
Implementation Method 4
The recording sheet is heated and pressed in the fusing nip so that the toner carried on the recording sheet can be heated and melted and thereby fused onto the recording sheet
Data Source
AI summary
A fusing apparatus for fusing a toner image onto a recording medium using heat and pressure includes a fusing roller; an endless pressing belt disposed opposite the fusing roller; and a pressing member for pressing the endless pressing belt onto the fusing roller. A recording medium with a transferred toner image is passed through a fusing nip between the fusing roller and the pressing belt. The fusing roller includes positive and negative crown portions along the axial direction. The pressing member includes convex and concave surface portions along the longitudinal direction. When the pressing member is pressed onto the fusing roller, the positive and negative crown portions of the fusing roller are engaged with the concave and convex surface portions, respectively, of the pressing member. The pressing member exerts a greater pressing force on the fusing roller at a central portion than at an end portion.