Vacuum Pulldown Print Media Fluting Reduction
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Solution Overview
Problem
Inkjet printing systems face issues with dimensional changes in print media due to moisture content, leading to flutes or wrinkles that affect image quality, as the media expands and contracts non-isotropically, causing friction with rollers and resulting in permanent creases and print quality degradation.
Innovation Solution
A printing system incorporating a vacuum assembly with a vacuum manifold aligned opposite a non-print zone of the print media to apply a vacuum force, adjusting the effective width of the manifold based on print job characteristics, which deflects the print media away from printheads, reducing friction and fluting, and includes additional vacuum assemblies for further stabilization and drying components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the print media is supported by a roller to prevent fluttering, then the print media stability is improved, but the friction between the print media and roller causes localized buckling and fluting
Solution Approach 1:
The patent uses a vacuum pulldown system where a vacuum source creates negative pressure to hold the print media against the roller. This pneumatic mechanism provides stable support without requiring high friction, thereby preventing both fluttering and fluting simultaneously
Solution Approach 2:
The patent changes the parameter of media support from friction-based mechanical contact to vacuum-based adhesive force. By adjusting the vacuum pressure parameter, the system achieves optimal balance between stability and flatness
2Quantity of substance
If drying is applied frequently to remove moisture, then the moisture content is reduced, but the dimensional characteristics of the print media change adversely
Solution Approach 1:
The patent implements periodic drying cycles rather than continuous drying. The vacuum pulldown system allows the media to pass through printing zones where moisture is added, then applies vacuum holding during drying zones, creating a rhythmic pattern that balances moisture removal with dimensional stability
Solution Approach 2:
The vacuum pulldown system maintains continuous contact with the print media throughout the printing and drying process, ensuring that the media remains stable and flat during both moisture addition and removal phases
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 vacuum system effectively reduces fluting and enhances print media stiffness, preventing contact with printhead support structures, thereby improving image quality by minimizing wrinkles and creases.
Implementation Method 1
The vacuum manifold is aligned with a non-print zone of each linehead and outputs a vacuum force proximate to the second side of the print media such that at least a portion of the second side of the print media is deflected away from the lineheads
Data Source
AI summary
A printing system includes one or more lineheads disposed opposite a first side of a print media and at least one vacuum assembly having a vacuum manifold disposed opposite a second side of the print media. The linehead or lineheads has one or more print zones where a liquid or ink is deposited onto the first side of the print media. The vacuum manifold is aligned with a non-print zone of each linehead and outputs a vacuum force proximate to the second side of the print media such that at least a portion of the second side of the print media is deflected away from the lineheads. The printing system can also include another component, such as a dryer, disposed over the print media and laterally adjacent to the linehead. Another vacuum manifold can be disposed adjacent to the second side print media between the linehead and the component.