Ink Jet Ink Layering for Wide Color Gamut and Fluorescence
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Solution Overview
Problem
Existing ink jet recording methods struggle to achieve 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, where the density of the pigment particle exceeds that of the fluorescent particle, allowing them to form distinct layers on the recording medium to enhance 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
Solution Approach 1:
The invention divides the ink system 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. This segmentation allows each ink to perform its specific function without interference - the pigment ink provides lightfastness while the fluorescent ink maintains high fluorescence intensity. The two inks are applied in a layered manner where the fluorescent ink is applied over the pigment ink, creating a structure where fluorescent particles are positioned above pigment particles, thus preventing pigment absorption of fluorescent light while ensuring lightfastness.
Solution Approach 2:
The invention introduces a vertical dimension to the ink layering by controlling the application sequence and utilizing density differences. The first ink (pigment) is applied first and forms a base layer, while the second ink (fluorescent particles) is applied afterward and forms an upper layer. This vertical arrangement in the third dimension ensures that fluorescent particles are positioned above pigment particles, allowing fluorescent light to emit upward without being absorbed by pigment, while still benefiting from the pigment layer's lightfastness protection.
2Reliability
If both fluorescent particles and pigment are contained in the same ink, then the lightfastness improves, but the expressible color gamut cannot be increased
Solution Approach 1:
The invention segments the ink formulation into two distinct inks with different functional compositions. The first ink is optimized for pigment concentration and lightfastness properties, while the second ink is optimized for fluorescent particle concentration and color gamut expansion. This segmentation allows independent optimization of each ink's properties without compromise, enabling both high lightfastness and wide color gamut when used in combination.
Solution Approach 2:
The invention creates a composite recording system by combining two different ink materials with complementary properties. The first ink provides a stable pigment-based foundation with excellent lightfastness, while the second ink adds fluorescent components that extend the expressible color gamut. The interaction between these two composite ink materials creates a synergistic effect where the overall performance exceeds what either ink could achieve alone.
3Adaptability or versatility
If fluorescent particles are used to achieve wide expressible color gamut, then the color gamut improves, but the lightfastness decreases due to degradation of fluorescent particles
Solution Approach 1:
The invention separates the fluorescent particles into a dedicated second ink that is applied over the pigment-containing first ink. This segmentation protects the fluorescent particles from direct contact with the recording medium and environmental factors that cause degradation, while still allowing them to contribute to wide color gamut. The pigment layer beneath provides a protective barrier that enhances the stability and lightfastness of the fluorescent particles.
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 enables recording of images with improved lightfastness and fluorescence intensity by minimizing pigment interference with fluorescent light emission and allowing for a wider color gamut through strategic layering of ink components.
Implementation Method 1
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. The coloring material having absorbed light transitions to an unstable excited state in which an energy state is high. Fluorescence refers to light emission that occurs when the coloring material returns from a singlet state in the excited state to a ground state.
Implementation Method 2
the fluorescence intensity of the image decreases. Such a decrease in the fluorescence intensity is assumed to occur because fluorescent light emitted from the fluorescent particle is scattered or absorbed by the pigment present on the fluorescent particle
Implementation Method 3
a pigment particle that is a pigment dispersed by an effect of an anionic group, the second ink contains a fluorescent particle dispersed by an effect of an anionic group
Implementation Method 4
a density ρ1 (g/cm3) of the pigment particle is more than a density ρ2 (g/cm3) of the fluorescent particle
Implementation Method 5
a density ρ1 (g/cm3) of the pigment particle is more than a density ρ2 (g/cm3) of the fluorescent particle
Data Source
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 ρ1 (g/cm3) of the pigment particle is more than a density ρ2 (g/cm3) of the fluorescent particle.