Inkjet Ink Layering for Wide Color Gamut and Fluorescence
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving a wide expressible color gamut and high fluorescence intensity due to the degradation of fluorescent particles and interference between fluorescent and pigment particles, leading to reduced lightfastness and fluorescence intensity.
Innovation Solution
An ink jet recording method involving the application of a first ink containing an alkaline buffer and a pigment particle dispersed by an anionic group, and a second ink containing a fluorescent particle also dispersed by an anionic group, with the pigment particle density exceeding that of the fluorescent particle, to form a layered image structure that enhances fluorescence intensity and color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pigment is added to an ink containing fluorescent particles to improve lightfastness, then the lightfastness of the recorded image improves, but the fluorescence intensity decreases due to scattering and absorption of fluorescent light by the pigment
Solution Approach 1:
The ink is divided into two separate inks: a first ink containing pigment particles dispersed by anionic groups, and a second ink containing fluorescent particles dispersed by anionic groups. These inks are applied separately to the recording medium, allowing the pigment and fluorescent particles to form distinct layers that do not interfere with each other's optical properties.
Solution Approach 2:
The solution transitions from a single-layer ink composition to a multi-layer structure by applying inks in sequence. The fluorescent particles form an upper layer while pigment particles form a lower layer, creating vertical separation that preserves both lightfastness and fluorescence intensity.
2Reliability
If both fluorescent particles and pigment are contained in the same ink to improve lightfastness, then the lightfastness improves, but the expressible color gamut cannot be increased due to fixed content ratios
Solution Approach 1:
The ink system is segmented into separate first and second inks with independent compositions. This allows flexible adjustment of pigment and fluorescent particle contents in each ink without being constrained by fixed ratio requirements, enabling expansion of the expressible color gamut while maintaining lightfastness.
3Adaptability or versatility
If fluorescent particles are used to achieve wide expressible color gamut and high fluorescence intensity, then the color gamut and fluorescence intensity improve, but the lightfastness decreases due to the unstable excited state of fluorescent coloring materials
Solution Approach 1:
The ink containing fluorescent particles is separated from the ink containing pigment particles. The pigment-rich first ink provides lightfastness protection, while the fluorescent particle-containing second ink maintains high fluorescence intensity and wide color gamut. The layered structure ensures that the unstable fluorescent particles are protected by the pigment layer below.
4Adaptability or versatility
If two types of inks are applied to overlap to increase expressible color gamut, then the color gamut increases, but the fluorescence intensity cannot be increased due to scattering and absorption effects
Solution Approach 1:
The patent applies different inks with different local qualities to specific areas of the recording medium. The first ink with pigment particles is applied to provide lightfastness and color, while the second ink with fluorescent particles is applied to provide fluorescence. The overlapping areas benefit from both properties without significant interference due to the layered structure and anionic group-based dispersion that prevents aggregation.
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 method achieves images with improved lightfastness and fluorescence intensity by minimizing pigment interference with fluorescent light emission and allowing for a wider color gamut through strategic ink application and density differences.
Implementation Method 1
a pigment particle that is a pigment dispersed by an effect of an anionic group
Implementation Method 2
The coloring material that exhibits fluorescence absorbs short-wavelength light corresponding to an ultraviolet to visible range and emits light with a wavelength longer than the wavelength of the absorbed light
Implementation Method 3
the density of the pigment particle is greater than that of the fluorescent particle, allowing for partial overlap on the recording medium to optimize layer formation
Data Source
Figure 1A
Figure 1B
AI summary
Provided is an ink jet recording method that enables recording of an image with a wide expressible color gamut and high fluorescence intensity. The ink jet recording method comprises a step of recording an image by applying first and second inks to a recording medium by using an ink jet recording apparatus, including a recording head having ejection orifices configured to eject the first and second inks, respectively, such that an area where the first ink is applied and an area where the second ink is applied at least partially overlap each other. The first ink contains an alkaline buffer and a pigment particle dispersed by an effect of an anionic group, the second ink contains a fluorescent particle dispersed by an effect of an anionic group, and a density pi (g/cm3) of the pigment particle is more than a density ρ2 (g/cm3) of the fluorescent particle.