Folding Roller Main Relief for Crease Prevention
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Solution Overview
Problem
Existing folding rollers cause creasing issues at the front edge during the folding process, especially at high speeds.
Innovation Solution
The folding roller design features a radially recessed main relief on the second axial portion, with specific angular ranges for the auxiliary and main reliefs, and additional features like grooves and cylindrical surfaces to prevent creasing by controlled gripping and releasing of the product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known folding rollers grip the central portion of the booklet at the front edge region, then the booklet can be folded, but creasing occurs in the region of the front edge at the location of the fold
Solution Approach 1:
The folding roller is divided into multiple axial portions (first, second, third axial portions) with different functions. The first axial portion has an auxiliary relief for releasing lateral portions, the second axial portion has a main relief for releasing the front edge region, and the third axial portion provides a continuous folding surface. This segmentation allows different regions of the roller to perform specific functions that prevent creasing while maintaining folding capability.
Solution Approach 2:
Different axial portions of the roller have different surface characteristics tailored to specific needs. The first folding surface and second folding surface are radially aligned to create a continuous folding path, while the reliefs create localized release zones. The auxiliary relief extends over 120°-160° angular range for lateral portion release, and the main relief extends over 270°-325° for front edge release, providing locally optimized surface properties.
2Productivity
If folding speed is increased to improve productivity, then output increases, but creasing issues worsen
Solution Approach 1:
The auxiliary relief on the first axial portion releases the lateral portions of the signature before the main folding action occurs. By预先 releasing the lateral portions, the roller ensures that only the necessary central portion remains gripped during high-speed folding, preventing lateral portions from causing creasing at the front edge even at high folding speeds.
Solution Approach 2:
The main relief on the second axial portion extracts or releases the front edge region of the signature during the folding process. By removing the gripping force from the front edge region at the appropriate moment, the roller prevents creasing while maintaining control over the central portion needed for folding, enabling high-speed operation without quality degradation.
3Force
If the roller grips the front edge region strongly to prevent slippage, then folding control improves, but creasing occurs at the fold location
Solution Approach 1:
The roller provides dynamic gripping force through its rotating motion and the strategic placement of reliefs. As the roller rotates, the auxiliary and main reliefs periodically release different regions of the signature, creating a dynamic gripping pattern that maintains control during folding while preventing excessive force concentration at the front edge fold location that would cause creasing.
Data Source
AI summary
A folding roller is provided for a device for folding a flat product to be folded which extends along a center axis and includes a first axial portion and a second axial portion, the first axial portion having a first surface for folding the product to be folded. The second axial portion includes a main relief which is radially recessed relative to the first folding surface.