Postal Blue Inkjet Ink Composition for High Contrast and Waterfastness
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Solution Overview
Problem
Existing blue postal inks face challenges in achieving high contrast and waterfastness while maintaining readability and reliability across diverse substrates, as high pigment concentrations can affect purging and decap properties, and existing formulations struggle to meet contradictory requirements for European and other postal standards.
Innovation Solution
A water-based blue inkjet ink composition combining C.I. Pigment Blue 60 with dyes, glycerol, and polyethylene glycol 200, along with a styrene acrylic copolymer dispersant, triethylene glycol monobutyl ether, and specific surfactants, which provides high contrast, waterfastness, and reliable print head operation on a range of substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of pigment and/or dyes are used to achieve waterfastness and high contrast, then waterfastness and contrast are improved, but purging and decap properties deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration ranges of pigments (0.1-5% wt) and dyes (0.1-5% wt) rather than using high concentrations. It also changes the chemical parameters by selecting specific solvent ratios (glycerol 10-50% wt, polyethylene glycol 200 5-30% wt) and adding surfactants (0.1-5% wt) to modify the ink's physical chemistry, enabling both waterfastness and good jetting performance without requiring high pigment loads
Solution Approach 2:
The patent creates a composite ink formulation combining multiple components: pigments (such as C.I. Pigment Blue 60), dyes, water-soluble organic solvents (glycerol and polyethylene glycol 200), surfactants, and optional additives. This composite approach allows the system to achieve waterfastness through the pigment-dye-solvent combination while the surfactants and solvent system maintain jetting performance, resolving the contradiction between reliability and ease of operation
2Reliability
If high concentrations of pigment and/or dyes are used to achieve high contrast, then contrast is improved, but purging and decap properties deteriorate
Solution Approach 1:
The patent achieves high contrast (≥70% on porous substrates) not through high pigment concentration but by optimizing the combination of pigment type (C.I. Pigment Blue 60), dye components, and solvent ratios. The controlled parameter ranges for pigments (0.1-5% wt) and dyes (0.1-5% wt) combined with specific surfactant concentrations (0.1-5% wt) enable high contrast while maintaining purging and decap performance
Solution Approach 2:
The composite ink system combines pigments, dyes, water-soluble organic solvents, and surfactants to achieve high contrast without requiring high pigment loads. The synergistic interaction between these components allows the ink to provide ≥70% contrast on porous substrates while the surfactant and solvent system prevents nozzle clogging, resolving the contradiction between contrast and ease of operation
3Adaptability or versatility
If a single blue postal ink is designed to satisfy all European and other postal requirements, then versatility is improved, but formulation complexity increases
Solution Approach 1:
The patent creates a universal blue postal ink formulation that simultaneously satisfies multiple contradictory requirements: waterfastness (≥80% OD retention), high contrast (≥70% on porous substrates), lightfastness (≥90% OD retention), fast drying time (<1s on US Type A envelopes), and good jetting performance. This multi-functional formulation works across diverse substrates including porous and coated envelopes, meeting various European and international postal standards with a single ink composition
Solution Approach 2:
The patent achieves versatility through carefully controlled parameter ranges rather than complex formulations. By specifying pigment concentrations of 0.1-5% wt, dye concentrations of 0.1-5% wt, glycerol 10-50% wt, polyethylene glycol 200 5-30% wt, and surfactants 0.1-5% wt, the formulation maintains simplicity while adapting to multiple postal requirements and substrate types
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 composition achieves high contrast (>70%) and waterfastness, ensuring reliable machine-readable images, particularly on porous and coated substrates, with improved jettability and lightfastness, meeting stringent regulatory requirements and maintaining performance over time.
Implementation Method 1
triethylene glycol monobutyl ether as a penetrant
Implementation Method 2
specific surfactants
Implementation Method 3
a styrene acrylic copolymer as a polymeric dispersant
Implementation Method 4
glycerol and polyethylene glycol 200 (i.e., MW 200) at a ratio of glycerol to polyethylene glycol of from 2:1 to 3.5:1 as water-soluble organic solvents
Data Source
AI summary
A water-based ink for inkjet recording exhibits a blue color defined as L*<45, 25<C*<28, 255<h<278, and comprises a mixture of dyes and pigments, glycerol and polyethylene glycol #200 as water-soluble organic solvents and a polymeric dispersant. The ink will preferably have a ratio of glycerol to polyethylene glycol 200 within the range of from 2:1 to 3.5 1. The water-based ink preferably includes C.I. Pigment Blue 60 as a colorant and provides good printing stability and good storage stability. Tests show the inks to have good jettability.