Curved Corner Bonding Pattern for Sheet Peeling Prevention
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Solution Overview
Problem
Existing image forming apparatuses face issues with unintentional peeling of sheets when the stress concentrates on the corner portions of the bonding pattern, leading to potential separation of sheets during handling.
Innovation Solution
The image forming apparatus includes an image forming unit that forms a visible image and a bonding pattern on a sheet using powder adhesive. The bonding pattern is designed with specific corner portions positioned at strategic ends of the pattern, and these corners are curved to minimize stress concentration, with the second and third corner portions having a greater radius of curvature than the first corner portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bonding pattern uses a right-angled triangle shape or rectangular shape with corner portions, then the bonding strength can be enhanced, but stress concentrates on the corner portions causing unintentional peeling of sheets
Solution Approach 1:
The patent applies curvature to the corner portions of the bonding pattern by replacing sharp corners with rounded arcs. Specifically, the first corner portion is replaced with a first arc and the second corner portion is replaced with a second arc, where each arc has a radius of curvature that is at least 10% of the length of the adjacent straight line portions. This curvature design distributes stress more evenly across the bonding pattern, preventing stress concentration at sharp corners while maintaining bonding strength, thereby eliminating unintentional peeling of sheets.
2Area of stationary object
If the corner portions are made sharp to maximize bonding area, then the bonding pattern coverage is optimized, but stress concentration increases leading to sheet peeling
Solution Approach 1:
The patent replaces sharp corner portions with curved arcs while maintaining the overall bonding pattern area. The first arc replaces the first corner portion and the second arc replaces the second corner portion, with each arc's radius of curvature being at least 10% of the adjacent straight line portions. This curvature modification redistributes stress away from concentrated points, preventing sheet peeling while preserving sufficient bonding area for effective sheet bonding.
3Strength
If the bonding pattern is extended to cover the entire sheet edge, then the bonding strength is maximized, but the complexity of the pattern increases and handling becomes difficult
Solution Approach 1:
The patent segments the bonding pattern into distinct components: straight line portions and curved arc portions. The bonding pattern consists of a first straight line portion, a first arc replacing the first corner portion, a second straight line portion, and a second arc replacing the second corner portion. This segmentation creates a modular structure that is easier to design, manufacture, and handle while maintaining effective bonding strength through the combination of straight and curved elements.
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 reduces the likelihood of unintentional peeling of sheets by distributing stress more evenly across the bonding pattern, enhancing the bonding strength and reliability of the sheet bundle.
Implementation Method 1
a bonding unit configured to heat a plurality of sheets in a stacked state, to bond the plurality of sheets together via the bonding pattern
Data Source
AI summary
An image forming apparatus includes an image forming unit configured to form a visible image and a bonding pattern on a sheet, and a bonding unit configured to heat a plurality of sheets in a stacked state, to bond the plurality of sheets together via the bonding pattern. The bonding pattern includes a first side portion, a second side portion, a third side portion, a first corner portion, a second corner portion, and a third corner portion. The second corner portion and the third corner portion are curved such that a minimum value of a radius of curvature of the second corner portion and a minimum value of a radius of curvature of the third corner portion are greater than a minimum value of a radius of curvature of the first corner portion.