UV Primer Coating for Ink Jet Drop Size Control
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Solution Overview
Problem
Existing ink jet printing systems face challenges in achieving precise drop size control, especially when multiple print heads are used or when the distance between the print head and substrate exceeds 1 mm, leading to imprecision in drop placement and requiring adaptations in drop spread to maintain print quality.
Innovation Solution
A radiation-curable primer coating composition is applied to the substrate, comprising a low surface tension monofunctional alkyl acrylate monomer, a photoinitiator, and other UV or cationic curable monomers and oligomers, which is cured before printing the ink jet ink, allowing for adjustment of the ink drop size by varying the amount of low surface tension monomer to achieve desired print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a standard radiation curable ink jet ink is used without a primer coating, then the printing process is simpler, but the drop size control is imprecise and print quality deteriorates when using multiple print heads or larger print head-to-substrate distances
Solution Approach 1:
A primer coating is applied to the substrate before the ink jet ink to pre-establish the desired surface properties. The primer coating contains low surface tension monomers that control ink drop spread, enabling precise dot size control before the ink is even deposited. This preliminary preparation resolves the drop size control issue without requiring complex real-time adjustments during printing.
Solution Approach 2:
The primer coating acts as an intermediary layer between the substrate and the ink jet ink. It mediates the interaction by providing a controlled surface that regulates ink drop spread and adhesion, thereby improving drop size control precision without requiring changes to the ink formulation or print head configuration.
2Adaptability or versatility
If the print head-to-substrate distance is increased to accommodate multiple print heads, then more print heads can be used, but drop placement precision deteriorates
Solution Approach 1:
The surface tension parameters of the substrate are modified by applying a primer coating with low surface tension monomers (23-31 dynes/cm). This parameter change in surface properties compensates for the increased print head-to-substrate distance, allowing multiple print heads to be used while maintaining drop placement precision through controlled ink drop spread on the primed surface.
3Measurement precision
If the theoretically optimal drop size (√2/DPI) is used, then maximum theoretical resolution is achieved, but print quality deteriorates when drop spread needs to be adjusted for misplacement compensation
Solution Approach 1:
The primer coating enables dynamic control of ink drop spread by adjusting the concentration of low surface tension monomers in the primer formulation. This creates an adaptable surface that can compensate for misplacement variations while maintaining high resolution, transforming the static drop size requirement into a dynamically adjustable parameter through surface chemistry control.
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 primer coating effectively controls and adjusts the drop size of the ink jet ink, resulting in finer print quality and reduced drop spread, enabling the use of multiple print heads and ink combinations while maintaining high print quality even at larger distances between the print head and substrate.
Implementation Method 1
The primer composition is then cured with actinic radiation
Implementation Method 2
a low surface tension monofunctional alkyl acrylate monomer with a surface tension in the range of 23 to 31 dynes/cm
Data Source
AI summary
The present invention provides a printing method for printing radiation-curable ink jet ink printing comprising a clear coat primer composition comprising: a low surface tension monofunctional alkyl acrylate monomer with a surface tension in the range of 23 to 31 dynes/cm in which the alkyl group has at least 8 carbon atoms; a photoinitiator; and other UV curable monomers and oligomers. The clear coat primer composition is applied first onto a substrate and cured with actinic radiation or cationic curable ink jet ink is printed on the surface of the clear coat primer coating.