Conformable Belt Leveling for UV-Curable Ink
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Solution Overview
Problem
Radiation-curable gel inks have a 'mayonnaise' consistency at room temperature, lacking cohesive strength and uniformity, making it challenging to level and cure them directly on substrates without smudging or uneven thickness, which is crucial for applications like packaging that require uniform gloss and thin layers.
Innovation Solution
A leveling apparatus with a conformable surface, comprising a fluorinated ethylene propylene inner layer and a silicone outer layer, along with a UV light source, is used to contact and cure the ink at a nip, ensuring uniform spreading and simultaneous curing, preventing ink offset and achieving consistent thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fuser roll methods are used to flatten ink, then ink leveling is achieved, but ink splits and leaves image behind on the device
Solution Approach 1:
The patent changes the physical parameters of the leveling surface by using a conformable coating with specific durometer (30-70 Shore A) that allows the viscous ink to spread and level without adhering to the surface. This parameter change in surface compliance resolves the contradiction between achieving ink leveling and maintaining image completeness.
Solution Approach 2:
The conformable coating acts as an intermediary between the rigid leveling device and the viscous ink. This intermediary layer provides the necessary compliance to level the ink without causing it to split or adhere, thus maintaining both leveling precision and image integrity.
2Manufacturing precision
If ink is leveled before UV curing, then uniform gloss and thickness are achieved, but ink lacks cohesive strength and spreads unevenly
Solution Approach 1:
The patent applies preliminary UV curing to the ink immediately after deposition, before the leveling process. This preliminary action creates sufficient cohesive strength in the ink to prevent spreading during leveling, while still allowing the conformable surface to achieve uniform thickness and gloss.
Solution Approach 2:
The patent merges the UV curing process with the leveling process by positioning the UV lamp to cure the ink while it is in contact with the conformable leveling surface. This combination ensures the ink maintains cohesive strength during leveling while achieving uniform thickness.
3Force
If rigid leveling surface is used, then leveling pressure is applied, but ink adheres to the device and offsets
Solution Approach 1:
The patent changes the parameter of surface rigidity by using a conformable coating with durometer 30-70 Shore A instead of a rigid surface. This parameter change allows the application of leveling pressure while preventing ink adhesion and offset through the compliant nature of the coating.
Solution Approach 2:
The conformable coating acts as a flexible thin film that conforms to the substrate surface and provides compliance during the leveling process. This flexibility prevents ink from adhering to the leveling device while still allowing sufficient pressure to be applied for uniform leveling.
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 enables uniform ink spreading and curing, reducing line width standard deviation, enhancing image quality by maintaining ink in a liquid state during jetting and curing, resulting in consistent thickness and gloss across the substrate.
Implementation Method 1
radiation suitable for curing the ink on the substrate
Implementation Method 2
A leveling member is positioned to contact an ink-bearing side of the substrate at a nip
Data Source
AI summary
Systems for leveling UV-curable gel ink include a leveling belt member having a TEFLON FEP inner layer and a conformable silicone outer layer. A UV source is disposed to direct light through the belt onto a substrate at a leveling or pressure nip defined by the leveling beltz tube and a backing member such as a backing belt and chilled platen.