Ink formulation for high black density and glossiness
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Solution Overview
Problem
Inkjet recording technologies face challenges in achieving high black density and glossiness, particularly with pigment inks on glossy paper, as they tend to suffer from glare and insufficient color developability compared to dye inks.
Innovation Solution
The development of an ink formulation that incorporates carbon black and resin fine particles, where the resin particles are swollen to increase their size and flexibility, forming a layer on the pigment layer to reduce voids and scattering, and using a specific water-soluble organic solvent with a dielectric constant of 18.0 to 30.0 to enhance absorption and glossiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carbon black is used as a coloring material in pigment ink, then color developability is improved, but glossiness and black density become insufficient due to light scattering and glare
Solution Approach 1:
The patent changes the physical state of the resin from solid particles to swollen gel状 particles by controlling the dielectric constant of the solvent, which transforms the resin's interaction with light and its ability to fill pigment layer voids, thereby improving both color developability and glossiness simultaneously
Solution Approach 2:
The patent creates a composite system where resin fine particles and carbon black pigment particles work together in a specific ratio and spatial arrangement, with the swollen resin particles filling voids between pigment particles to reduce light scattering while maintaining color intensity
2Illumination intensity
If resin emulsion is added to suppress glare, then glossiness is improved, but black density reduces due to white light reflection
Solution Approach 1:
The patent changes the physical state of resin from liquid emulsion to swollen gel状 fine particles, which alters their optical properties and ability to fill voids, allowing them to improve glossiness without causing white light reflection that would reduce black density
Solution Approach 2:
The patent applies resin fine particles specifically to fill voids within the pigment layer rather than forming a surface layer, creating local density improvements that enhance glossiness without creating reflective surfaces that would reduce black density
3Measurement precision
If resin fine particles are incorporated to improve color developability, then color intensity increases, but glossiness remains insufficient due to surface irregularities
Solution Approach 1:
The patent changes the swelling state of resin fine particles by controlling solvent dielectric constant, enabling the particles to expand and fill surface irregularities and internal voids, thereby achieving both color developability and glossiness improvements
Solution Approach 2:
The patent pre-swells the resin fine particles before ink application, so that they are already in an expanded state ready to fill voids and create a smooth surface upon deposition, rather than requiring post-deposition swelling that would be insufficient for glossiness
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 achieves improved black density and glossiness by reducing surface and internal scattering, resulting in a more vivid and glare-free image on glossy paper.
Implementation Method 1
using a specific water-soluble organic solvent with a dielectric constant of 18.0 to 30.0 to enhance absorption and glossiness
Implementation Method 2
the internal scattering of light occurs owing to voids in a pigment layer, and light thus generated is observed as the reflected light of the image
Data Source
AI summary
Provided are an ink with which an image excellent in both black density and glossiness can be recorded, and an ink cartridge and an ink jet recording method each using the ink. The ink includes: a carbon black; a resin for dispersing the carbon black; a resin fine particle; and a water-soluble organic solvent, in which: the resin fine particle contains at least a unit derived from an ethylenically unsaturated hydrophobic monomer, and a unit derived from a monomer selected from an ethylenically unsaturated acid monomer and a salt thereof, and a ratio of a unit derived from a saturated alkyl group-containing monomer to the unit derived from the ethylenically unsaturated hydrophobic monomer is 95.0 mass% or more; and the water-soluble organic solvent contains a water-soluble organic solvent having a dielectric constant at 20°C of 18.0 or more and less than 30.0.