White Ink Recording Method for Uniform Opacity
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Solution Overview
Problem
Ink jet recording methods using white ink with a reaction liquid often result in low image quality, low L* value, and poor opacity due to ink spreading and coffee stain effects, limiting the amount of ink that can be ejected per unit area.
Innovation Solution
A recording method involving a white ink composition with a white coloring material and a first resin, where the resin's average particle size increases significantly upon mixing with magnesium sulfate, and optionally a clear ink composition with a second resin, applied in a wet-on-wet manner to enhance viscosity and aggregation, improving image quality and opacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white ink composition is applied with high amount to improve opacity and L* value, then image quality improves, but ink spreading and coffee stain effects occur causing non-uniform deposition
Solution Approach 1:
A clear ink composition containing second resin fine particles is applied in advance to the recording medium before applying the white ink composition. This preliminary action creates a foundation layer that prevents subsequent ink spreading and coffee stain effects, enabling high amount of white ink to be deposited uniformly.
Solution Approach 2:
The invention uses a composite system consisting of clear ink composition (with second resin) and white ink composition (with first resin). The two resin systems work together synergistically - the second resin provides structural framework while the first resin provides opacity, achieving both high L* value and uniform deposition.
2Manufacturing precision
If reaction agent is added to aggregate particles and increase viscosity, then ink deposition control improves, but particle aggregation may reduce image quality
Solution Approach 1:
The reaction agent is applied locally and selectively to aggregate only the first resin fine particles in the white ink composition, while the second resin fine particles in the clear ink composition remain unaggregated. This local differentiation allows controlled deposition without compromising image quality.
Solution Approach 2:
The clear ink composition containing unaggregated second resin particles is applied in advance to create a uniform foundation. Subsequently, the reaction agent aggregates the first resin particles in the white ink, allowing controlled deposition on top of the pre-formed uniform layer.
3Illumination intensity
If single resin system is used in white ink, then formulation is simple, but cannot achieve both high opacity and uniform deposition
Solution Approach 1:
The resin system is segmented into two distinct components: first resin fine particles (in white ink) responsible for opacity, and second resin fine particles (in clear ink) responsible for uniform deposition. Each resin type performs its specific function independently, achieving both goals simultaneously.
Solution Approach 2:
The invention employs a composite resin system where first resin and second resin work together. The clear ink composition provides uniform deposition through second resin, while the white ink composition provides opacity through first resin, creating a synergistic effect that neither resin could achieve alone.
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 increases the L* value and opacity of the recorded article while allowing for a higher amount of ink to be ejected per unit area, reducing clogging and improving image formability.
Implementation Method 1
The reaction agent increases the viscosity of the white ink composition or aggregates the constituent particles in the white ink composition
Implementation Method 2
when each of a liquid of the first resin in water and a liquid of the second resin in water is mixed with an aqueous solution of magnesium sulfate, the magnitude of increase in average particle size of the first resin is larger than the magnitude of increase in average particle size of the second resin
Implementation Method 3
the application of the white ink composition and the application of the clear ink composition are performed in a state where both the white ink composition and the clear ink composition are wet
Data Source
AI summary
A recording method includes applying a white ink containing a white material and a first resin onto a predetermined region of a recording medium, and applying a reaction liquid containing a reaction agent onto at least the predetermined region. Further, the recording method includes applying a clear ink containing a second resin onto at least the predetermined region, and the application of the white ink and the clear ink are performed while the white ink and the clear ink are both wet; and/or the white ink further contains the second resin. When either the first resin and water, or the second resin and water, is mixed with an aqueous solution of magnesium sulfate, the average particle size of the first resin increases more than the second resin.