Water-based Ink Re-dispersion via Polymeric Mediator
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Solution Overview
Problem
Water-based inks for ink-jet recording using self-dispersible pigments treated with phosphate groups face issues with re-dispersion properties and optical density, leading to potential jetting stability problems and suboptimal print quality.
Innovation Solution
Incorporating a phosphate group-modified self-dispersible pigment, a N-hydroxy cyclic imide compound, and at least one of boric acids, a chelate agent, a reducing sugar, or a sugar alcohol into the water-based ink to enhance re-dispersion properties and achieve higher optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a self-dispersible pigment treated with phosphate group is used, then optical density is improved, but re-dispersion property deteriorates
Solution Approach 1:
The patent introduces a polymeric pigment dispersant as an intermediary substance that mediates between the phosphate group-modified pigment particles and the aqueous medium. This dispersant contains hydrophilic groups that interact with the phosphate groups on pigment surfaces, enabling effective re-dispersion of dried pigment deposits without compromising the high optical density achieved through phosphate modification.
Solution Approach 2:
The invention creates a composite ink formulation combining phosphate group-modified self-dispersible pigment with polymeric pigment dispersant. This composite system leverages the high optical density properties of phosphate-modified pigment while the polymeric dispersant component provides re-dispersion capability, thus resolving the contradiction between these two properties.
2Illumination intensity
If a self-dispersible pigment treated with phosphate group is used, then optical density is improved, but jetting stability deteriorates
Solution Approach 1:
The polymeric pigment dispersant serves as a mediator that prevents direct aggregation of phosphate-modified pigment particles in the ink formulation. By adsorbing onto pigment surfaces through interactions with phosphate groups, it maintains individual particle separation and stable suspension, ensuring consistent jetting performance while preserving the high optical density of phosphate-modified pigment.
Solution Approach 2:
The patent modifies the chemical parameters of the ink formulation by introducing polymeric dispersant with specific molecular weight and functional group characteristics. This parameter change transforms the ink from a unstable suspension of phosphate-modified pigment into a stable colloidal system, enabling reliable jetting while maintaining high optical density.
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 significantly improves re-dispersion properties and optical density of the water-based ink, ensuring stable jetting and high-quality prints by aggregating pigment particles effectively.
Implementation Method 1
a self-dispersible pigment modified by phosphate group; water
Implementation Method 2
a N-hydroxy cyclic imide compound; and at least one selected from the group consisting of boric acids, a chelate agent, a reducing sugar and a sugar alcohol
Data Source
AI summary
A water-based ink for ink-jet recording includes a self-dispersible pigment modified by phosphate group; water; a water-soluble organic solvent; a N-hydroxy cyclic imide compound; and at least one selected from the group consisting of boric acids, a chelate agent, a reducing sugar and a sugar alcohol.