Ink Set Pigment Aggregation for High-Resolution Inkjet Recording
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Solution Overview
Problem
Inkjet recording technologies face challenges in achieving high-resolution images with sufficient rub resistance and preventing white spots, especially in high-speed printing using a single pass system, where color density, fixing property, and resolution are compromised.
Innovation Solution
An ink set comprising an aqueous ink composition with a pigment coated by a water-insoluble resin copolymer having a neutralization degree of 70% to 95% and an acid-containing aqueous liquid composition that aggregates the pigment, enhancing dispersion stability and preventing white spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high speed inkjet recording is performed using a single pass system, then productivity is improved, but manufacturing precision (resolution and color density) deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the ink composition by introducing a specific aqueous liquid composition containing an acid that aggregates pigment particles. This parameter change enables the ink to form appropriate pigment aggregates that improve resolution and color density while maintaining high-speed recording capability
Solution Approach 2:
The patent creates a composite ink system combining aqueous ink composition with specific pigment particles and an aqueous liquid composition containing acid. This composite material approach allows the pigment to aggregate in a controlled manner, achieving both high productivity and high manufacturing precision
2Reliability
If pigment particles are used to achieve water resistance and light resistance, then reliability is improved, but manufacturing precision (color density and resolution) deteriorates
Solution Approach 1:
The patent controls the particle diameter parameter of pigment particles to be 150 nm or more, and introduces an aqueous liquid composition with acid to aggregate these particles. This parameter control enables the pigment to maintain water resistance while achieving sufficient color density and resolution
Solution Approach 2:
The aqueous liquid composition containing acid acts as an intermediary that aggregates pigment particles into appropriate structures. This intermediary substance allows the pigment to maintain its water-resistant properties while forming aggregates that improve color density and resolution
3Reliability
If pigment particles are aggregated to improve fixing property, then reliability is improved, but object-generated harmful factors (white spots) increase
Solution Approach 1:
The patent precisely controls the particle diameter parameter of pigment particles and the concentration of acid in the aqueous liquid composition. This parameter control ensures proper pigment aggregation for fixing property while preventing excessive aggregation that would cause white spots
Solution Approach 2:
The patent applies the aqueous liquid composition locally to aggregate pigment particles only where needed for fixing property, while controlling the acid concentration and particle size to prevent harmful aggregation effects such as white spots in the final image
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 enables the formation of high-resolution images with excellent rub resistance and reduced white spots, improving maintenance efficiency and image quality in high-speed inkjet recording.
Implementation Method 1
a pigment coated with a water-insoluble resin which is a copolymer containing a repeating unit having an acid group and has a neutralization degree of from 70% to 95%
Implementation Method 2
an aqueous liquid composition containing an acid that aggregates the pigment in the aqueous ink composition when the aqueous liquid composition is mixed with the aqueous ink composition
Data Source
AI summary
The present invention provides an ink set for inkjet recording and an image recording method using the ink set, the ink set being composed of an aqueous ink composition containing a pigment coated with a water-insoluble resin that is a copolymer containing a repeating unit having an acid group and has a neutralization degree of from 70% to 95%, an organic solvent and water, and an aqueous liquid composition containing an acid that aggregates the pigment in the aqueous ink composition when the aqueous liquid composition is mixed with the aqueous ink composition, and the ink set being capable of forming, by using an aged ink, a high-resolution image that is free from white spots and is excellent in rub resistance.