Concave Drive Roller Reducing Web Wrinkling
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Solution Overview
Problem
Inkjet printing systems face issues with wrinkling of receiver media due to non-isotropic expansion and contraction caused by moisture absorption, leading to image quality degradation, and existing drive roller configurations struggle to accommodate a wide range of web widths and prevent web breaks during startup.
Innovation Solution
A drive roller configuration with a concave surface profile and nip rollers positioned in the central section, providing a constant outer diameter and recesses to accommodate media expansion and ensure reliable engagement across various widths, reducing wrinkling and web breaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional drive roller with uniform diameter is used, then the structure is simple and easy to manufacture, but it cannot accommodate media expansion and causes wrinkling
Solution Approach 1:
The drive roller employs a concave surface profile with varying radius of curvature along its length. The central section has a smaller radius of curvature than the end sections, creating a concave shape that allows media to expand into the recesses during ink absorption, preventing wrinkling while maintaining structural integrity
Solution Approach 2:
Different sections of the drive roller have different surface properties. The central section features a smaller radius of curvature to accommodate media expansion, while the end sections have larger radii. This localized variation in geometry allows the roller to address specific wrinkle-prone areas without over-complicating the entire structure
2Adaptability or versatility
If nip rollers are positioned at the ends of the drive roller, then the structure is simple, but it cannot accommodate a wide range of web widths and causes web breaks during startup
Solution Approach 1:
The nip rollers are repositioned from the traditional end positions to the central section of the drive roller, utilizing the concave region. This dimensional repositioning allows the nip rollers to engage media of varying widths effectively, preventing web breaks during startup while accommodating a wide range of web widths through the flexible concave geometry
3Manufacturing precision
If the drive roller has a constant diameter, then the surface velocity is uniform, but it cannot provide lateral stretching force to reduce wrinkling
Solution Approach 1:
The concave surface profile with varying radius of curvature creates regions of different surface velocity. The central section with smaller radius rotates at different linear speed compared to the end sections, generating lateral stretching forces that counteract media contraction and wrinkling while maintaining overall functional speed uniformity
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 reduces media wrinkling by applying lateral stretching forces and maintaining constant surface velocity, allowing for media expansion and accommodating a range of web widths, thereby enhancing image quality and system reliability.
Implementation Method 1
contact between the receiver media 3 and contact surface 8 of rollers 2 (or other web guiding components) in the inkjet printing system can produce sufficient friction such that the receiver media 3 is not free to slide in the cross-track direction 7
Implementation Method 2
a force to move the web of media along the transport path
Data Source
AI summary
A web-guiding system for guiding a web of media along a transport path comprising a drive roller rotated by a motor and a plurality of nip rollers. The drive roller includes a first section, a second section and a third section along the length of the roller, the second section being located between the first section and the third section. A diameter of a surface envelope around the exterior surface of the drive roller is substantially constant within the second section, and is larger in the first section and the third section than in the second section. The nip rollers are aligned with the second section of the drive roller, with the web of media passing between the drive roller and the nip rollers.