Aqueous Ink with Radical-Trapping Compound for Kogation Control
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Solution Overview
Problem
Ink jet recording systems using thermal energy face challenges with kogation occurrence when employing aqueous inks containing self-dispersible pigments, leading to reduced recording quality and increased maintenance needs.
Innovation Solution
An aqueous ink formulation incorporating a compound represented by General Formula (I), which reduces thermal action and oxidation of self-dispersible pigments, thereby minimizing kogation and enhancing image quality by leveraging the compound's affinity to both hydrophobic and hydrophilic areas of the pigment, and its radical trapping capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If aqueous inks containing self-dispersible pigments are used in thermal energy-based ink jet recording, then high optical density and recording quality are achieved, but kogation occurrence increases
Solution Approach 1:
The patent introduces a specific compound (with sulfonic acid, carboxylic acid, phosphoric acid, or phosphonic acid groups) as an intermediary substance that mediates between the self-dispersible pigment and the thermal recording head. This compound acts as a protective intermediary that prevents direct harmful interaction between the pigment and the thermal head, thereby reducing kogation while maintaining the pigment's high optical density properties.
Solution Approach 2:
The patent changes the chemical parameters of the ink formulation by incorporating specific compounds with defined functional groups (sulfonic acid, carboxylic acid, phosphoric acid, or phosphonic acid groups). This parameter change in the ink composition modifies the thermal and chemical behavior of the self-dispersible pigment, reducing its tendency to cause kogation on the thermal recording head while preserving image quality.
2Illumination intensity
If self-dispersible pigments are used as coloring material, then high optical density is achieved, but thermal action and oxidation increase leading to kogation
Solution Approach 1:
The patent employs a compound with specific functional groups as a protective intermediary that surrounds and protects the self-dispersible pigment particles. This intermediary layer reduces the thermal action and oxidation effects on the pigment, thereby improving thermal stability and reliability while maintaining the high optical density characteristics of the self-dispersible pigment.
Solution Approach 2:
The patent creates a composite ink formulation by combining self-dispersible pigments with specific compounds (having sulfonic acid, carboxylic acid, phosphoric acid, or phosphonic acid groups). This composite material approach integrates the high optical density properties of self-dispersible pigments with the thermal stability and oxidation resistance provided by the added compound, achieving both high image quality and reduced kogation.
3Productivity
If ink jet recording speed is increased, then productivity improves, but kogation occurrence increases due to higher recording frequency and amount
Solution Approach 1:
The patent applies preliminary action by incorporating the protective compound into the ink formulation before the recording process begins. This compound pre-provides protection against kogation, allowing the system to operate at high recording speeds and frequencies without the kogation that would normally accumulate. The protective mechanism is already in place, enabling high productivity without the harmful side effects.
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 effectively reduces kogation occurrence, maintaining high optical density and recording quality while being compatible with thermal energy-based recording heads, thus addressing the limitations of existing ink formulations.
Implementation Method 1
its radical trapping capabilities
Implementation Method 2
reduces thermal action and oxidation of self-dispersible pigments
Implementation Method 3
a recording head that ejects an ink by the action of thermal energy
Data Source
AI summary
An aqueous ink containing a self-dispersible pigment for use in an ink jet recording method using a recording head that ejects an ink by an action of thermal energy. The aqueous ink contains a compound represented by General Formula (I):where in General Formula (I) R1's are independently of each other, a sulfonic acid group, a carboxylic acid group, a phosphoric acid group or a phosphonic acid group, R2 is a hydrogen atom or an alkyl group, and n is an integer of 1 to 5.