Photo-Curable Ink Set Surface Tension for Clear Ink Spreading
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Solution Overview
Problem
Existing ink jet recording methods using photo-curable inks face issues with the clear ink composition failing to wet and spread sufficiently over the color ink coating, leading to poor line width and image quality.
Innovation Solution
A photo-curable ink jet ink set comprising an undercoating ink containing a (meth)acrylic acid ester with a vinyl ether group and higher surface tension, and an overcoating ink with a lower surface tension, ensuring a difference of at least 5 mN/m, along with specific surfactant and polymerizable compound compositions to enhance wetting and spreading properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the clear ink composition is applied over the color ink coating with conventional surface tension relationships, then the coating process can be completed, but the line width of the clear ink becomes very small and the clear ink cannot wet the surface or spread sufficiently
Solution Approach 1:
The invention changes the surface tension parameter of the undercoating ink by selecting specific polymerizable compounds with appropriate surface tension values (20-40 mN/m). This parameter adjustment ensures that the undercoating ink creates an optimal surface for the overcoating clear ink to wet and spread properly, resolving the contradiction between achieving sufficient line width and maintaining good wetting properties.
Solution Approach 2:
The invention uses composite material composition by combining specific polymerizable compounds (acrylic acid esters, vinyl ether compounds, and their copolymers) in the undercoating ink formulation. This composite approach creates a coating surface with optimized interfacial properties that enable both adequate line width and sufficient wetting of the overcoating clear ink.
2Reliability
If the undercoating ink has higher surface tension than the overcoating ink, then the overcoating ink can wet and spread properly, but the composition complexity increases
Solution Approach 1:
The invention simplifies the composition complexity by focusing on controlling the surface tension parameter through selective use of specific polymerizable compounds rather than adding multiple surfactants or complex additives. The surface tension is controlled within 20-40 mN/m range using readily available acrylic and vinyl ether compounds, achieving good wetting without complicating the formulation.
3Manufacturing precision
If photo-curable inks are used to form images with high fastness, then image quality improves, but the wetting and spreading of overcoating ink becomes insufficient
Solution Approach 1:
The invention resolves the contradiction by adjusting the surface tension parameter of the undercoating photo-curable ink to 20-40 mN/m using specific polymerizable compounds. This parameter optimization allows the undercoating to provide both high image quality (through proper curing) and adequate wetting surface for the overcoating clear ink, eliminating the need to compromise either property.
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 ink set achieves improved wetting and spreading of overcoating ink on undercoating ink, resulting in enhanced image quality with stable ejection and curing properties, while maintaining storage stability and reducing viscosity.
Implementation Method 1
The undercoating photo-curable ink jet ink contains a (meth)acrylic acid ester having a vinyl ether group... The undercoating photo-curable ink jet ink has a higher surface tension than the overcoating photo-curable ink jet ink
Implementation Method 2
photo-curable inks that can be cured by being irradiated with light (ultraviolet light) have been used in recent years
Data Source
AI summary
A photo-curable ink jet ink set includes an undercoating photo-curable ink jet ink containing a (meth)acrylic acid ester having a vinyl ether group expressed by general formula (I), and an overcoating photo-curable ink jet ink. The undercoating photo-curable ink jet ink has a higher surface tension than the overcoating photo-curable ink jet ink.