Inkjet Ink Composition with Crosslinked Dispersant Polymer
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Solution Overview
Problem
Existing inkjet recording technologies face issues with ink-ejection reliability and the formation of defects like white spots due to insufficient fixing properties and stability, particularly at high-speed printing, and conventional ink compositions lack sufficient stability and maintenance performance.
Innovation Solution
An inkjet ink composition comprising a pigment coated with a dispersant polymer, a water-soluble polymerizable compound, and a polymerization initiator, where the dispersant polymer is formed by crosslinking a water-soluble dispersant with a crosslinking agent, and an ink set including this composition and a treatment liquid with a coagulant, which enhances ink-ejection stability and prevents defects such as white spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If resin fine particles are incorporated and fixed at high temperature to improve fixing properties, then water resistance and fixing properties are improved, but ink-ejection reliability deteriorates over time and aggregates form around inkjet heads
Solution Approach 1:
The patent changes the chemical state of the binder from thermal fixation to photo-polymerization. Instead of relying on thermal properties of resin particles, the invention uses a polymerizable compound that undergoes photo-polymerization to form a crosslinked network, fundamentally changing the fixing mechanism from thermal to chemical transformation.
Solution Approach 2:
The patent replaces the thermal fixation mechanism with a photo-chemical mechanism. The polymerizable compound containing acrylate monomers and oligomers undergoes photo-polymerization when exposed to UV light, substituting the mechanical/thermal binding process with a chemical reaction that forms permanent crosslinked structures.
2Productivity
If conventional ink composition is used for high-speed recording, then productivity is improved, but image quality deteriorates due to pigment remaining on surface and insufficient liquid penetration
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by introducing a polymerizable compound with specific molecular weight and functional group content. This changes the interaction between ink components and recording medium, enabling better penetration at high speeds while maintaining image quality through controlled polymerization.
Solution Approach 2:
The patent creates a composite ink system combining pigment particles, polymerizable compounds, and initiators. This composite formulation allows the pigment to be carried by the polymerizable matrix, improving liquid penetration and reducing surface residue during high-speed recording while ensuring proper fixation through subsequent polymerization.
3Ease of operation
If ink composition lacks sufficient stability, then ease of operation is improved, but reliability deteriorates due to aggregate formation and white spots in recorded images
Solution Approach 1:
The patent incorporates the polymerizable compound and initiator into the ink composition in advance, preparing the system for controlled polymerization during or after recording. This preliminary preparation ensures that the ink remains stable for easy operation during storage and ejection, while the polymerization action is activated at the appropriate time to prevent aggregate formation and eliminate white spots.
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 proposed solution provides excellent ink-ejection reliability over time and prevents defects like white spots, ensuring high-quality image formation without issues related to ink bleeding or uneven printing, even at high speeds.
Implementation Method 1
the dispersant polymer being formed from a water soluble dispersant by crosslinking with a crosslinking agent
Implementation Method 2
a reaction liquid that contains a photo-polymerization initiator and an ink composition that contains acrylate monomers and oligomers are applied onto a recording medium, and the recording medium is irradiated with UV-light
Data Source
Figure 1
AI summary
The present invention provides an inkjet ink composition, which has excellent ink-ejection reliability over a long time and capability of forming an image without defects such as white spots, and which includes: a pigment coated with a dispersant polymer; a water soluble polymerizable compound; a polymerization initiator; and water, the dispersant polymer being formed from a water soluble dispersant by crosslinking with a crosslinking agent.