Ink Composition with Surface-Treated Pigment for Stable Ejection
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Solution Overview
Problem
Ink jet recording methods using water-soluble dyes result in poor water and light resistance, while pigment-based inks face issues with insufficient fixing properties and ejection stability due to high viscosity and air bubble generation.
Innovation Solution
An ink composition combining a resin emulsion and surface-treated pigment, with controlled amounts of monomers and oligomers, is used to enhance fixing properties and ejection stability, incorporating specific monomers and surfactants to maintain low viscosity and prevent foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pigment concentration is increased to increase print density, then print density is improved, but ink viscosity rapidly increases causing ejection instability
Solution Approach 1:
A surface-treated pigment acts as an intermediary between the pigment particles and the aqueous medium. The surface treatment creates a compatibility layer that prevents aggregation, allowing high pigment concentration without proportional viscosity increase. This mediator enables the ink to maintain low viscosity while achieving high print density through efficient pigment utilization.
Solution Approach 2:
The invention changes the surface properties of pigment particles through chemical treatment, modifying their interaction with the continuous phase. This parameter change at the particle surface level allows for high pigment loading while maintaining fluidity and ejection stability, resolving the contradiction between density and viscosity.
2Reliability
If pigment is used as coloring agent, then water resistance and light resistance are improved, but fixing properties become insufficient causing poor rubbing resistance
Solution Approach 1:
The invention creates a composite structure where surface-treated pigment particles are embedded in a resin binder matrix. This composite approach combines the water and light resistance of pigment with the adhesive properties of resin, achieving both durability and fixing strength simultaneously. The resin component provides the binding force necessary for good rubbing resistance while the pigment maintains its protective qualities.
3Stability of the object's composition
If polymeric dispersing agent is used to disperse pigment, then dispersion stability is improved, but air bubble generation increases reducing defoaming properties
Solution Approach 1:
The invention extracts and eliminates the problematic polymeric dispersing agent from the system by using surface-treated pigment instead. The surface treatment on pigment particles provides inherent dispersibility without requiring additional polymeric agents, thereby removing the source of air bubble generation while maintaining dispersion stability.
4Strength
If resin is added to improve fixing properties, then rubbing resistance is improved, but ink viscosity increases affecting ejection stability
Solution Approach 1:
The invention applies resin locally at the interface between the ink and recording medium rather than uniformly throughout the bulk ink. The surface-treated pigment concentrates the functional properties where needed for fixing, while the bulk ink maintains low viscosity for stable ejection. This localized quality distribution resolves the contradiction between fixing strength and ejection stability.
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 composition achieves sufficient fixing properties, high density, and stable ejection and storage stability, preventing nozzle clogging and unpleasant odors, while maintaining high image quality and water resistance.
Implementation Method 1
This resin is considered to firmly fix the pigment onto the recorded matter as a binder
Implementation Method 2
a surface-treated pigment ink in which only a pigment can be dispersed in an aqueous solvent even when a dispersing agent such as the surfactant or polymeric dispersing agent as described above does not exist
Data Source
AI summary
The invention provides an ink composition for ink jet recording comprising at least a resin emulsion and a surface-treated pigment, wherein the amount of monomers and oligomers with a molecular weight of 2,000 or less contained in the resin emulsion is 1,000 ppm or less based on the total amount of the ink composition. Also disclosed are an ink jet recording method using the ink composition and recorded matter obtained by the recording method.