Aqueous Ink Dynamic Surface Tension Control for High-Speed Recording
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Solution Overview
Problem
Existing aqueous inks for inkjet recording systems face challenges in achieving high image density and fixing ability, particularly on recording media with varying textures and permeation speeds, leading to issues like white stripes and insufficient image quality during high-speed recording.
Innovation Solution
An aqueous ink formulation comprising water, a water-soluble organic solvent, a water-insoluble coloring material, a surfactant, and a poor medium or salt, with specific dynamic surface tension characteristics to control the aggregation and permeation of the coloring material, ensuring high image density and fixing ability across different recording media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pigment particles are caused to aggregate on the surface of the recording medium to enhance image density, then image density is improved, but the area factor (surface coverage) becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by introducing specific water-soluble organic solvents (acetone, methyl ethyl ketone, ethyl acetate) with controlled ratios. This composition adjustment modifies the ink's interaction with the recording medium, enabling simultaneous achievement of high image density and adequate surface coverage without excessive pigment aggregation.
Solution Approach 2:
The patent creates a composite ink formulation combining water, multiple water-soluble organic solvents, pigment particles, and surfactants. This composite material works synergistically to control pigment behavior, allowing the ink to achieve both high image density and sufficient area factor through the combined effects of its components.
2Area of stationary object
If the amount of ink applied is increased to achieve sufficient area factor, then surface coverage is improved, but drying time increases causing print-through
Solution Approach 1:
The patent modifies the ink's evaporation characteristics by incorporating water-soluble organic solvents with different volatility. The specific ratio of acetone, methyl ethyl ketone, and ethyl acetate creates an optimized evaporation profile that ensures rapid initial drying to prevent print-through, while maintaining sufficient surface coverage through controlled pigment deposition.
3Area of stationary object
If the permeability of ink into the recording medium is improved to increase area factor, then surface coverage is enhanced, but image density becomes insufficient due to depth-wise permeation
Solution Approach 1:
The patent adjusts the ink's rheological and chemical parameters by controlling the composition of water-soluble organic solvents and surfactant concentration. This creates an ink formulation with optimized permeation characteristics that allows controlled surface penetration to achieve adequate area factor while preventing excessive depth-wise permeation, thereby maintaining high image density.
4Productivity
If high-speed continuous recording is conducted, then productivity is improved, but white stripes occur due to insufficient drying time
Solution Approach 1:
The patent optimizes the ink's evaporation and drying parameters through the specific composition of water-soluble organic solvents. The controlled volatility profile enables rapid drying that keeps pace with high-speed recording, preventing the formation of white stripes and maintaining image quality even during continuous high-speed operation.
Solution Approach 2:
The patent ensures continuous effective drying action through the optimized solvent composition. The ink formulation maintains appropriate drying characteristics throughout the recording process, ensuring that each successive recording pass occurs on sufficiently dried previous passes, thereby preventing defects during high-speed continuous recording.
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 excellent image density and fixing ability on various recording media, preventing white stripes during high-speed recording by maintaining optimal dynamic surface tension and aggregation of the coloring material, even with small ink droplet volumes.
Implementation Method 1
a dynamic surface tension of the aqueous ink at a lifetime of 50 milliseconds determined by a maximum bubble pressure method is higher than 47 mN/m, and a dynamic surface tension at a lifetime of 5,000 milliseconds determined by the maximum bubble pressure method is 38 mN/m or lower
Implementation Method 2
controlling the permeation of the ink into the recording medium and the aggregation of a coloring material in the ink
Data Source
AI summary
Provided herein is an aqueous ink, which is excellent in both image density and fixing ability irrespective of the kind of a recording medium even when the volume of an ink droplet is small and has such excellent properties that white stripes are not caused even when high-speed recording is conducted. The aqueous ink comprises at least water, a water-soluble organic solvent, a water-insoluble coloring material, a surfactant and a poor medium for the water-insoluble coloring material and/or a salt. The dynamic surface tension of the aqueous ink at a lifetime of 50 milliseconds determined by a maximum bubble pressure method is higher than 47 mN/m, and the dynamic surface tension at a lifetime of 5,000 milliseconds determined by the maximum bubble pressure method is 38 mN/m or lower.