Self-Dispersible Pigment Ink Set for Stable Ejection
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Solution Overview
Problem
Ink jet recording methods using pigment-based inks face issues with inferior color developability and unnecessary ink aggregation, leading to irregular ejection and deposition on recording heads and media during recovery operations.
Innovation Solution
An ink set comprising cyan, magenta, and yellow inks, where two inks contain self-dispersible pigments with phosphonic acid groups and the third ink contains self-dispersible pigments with sulfonic acid or carboxylic acid groups, inhibiting unnecessary ink aggregation and improving color developability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If self-dispersible pigments with high reactivity to calcium are used to improve color developability, then color image quality is enhanced, but unnecessary ink aggregation occurs during recovery operations
Solution Approach 1:
The patent changes the chemical parameter of the functional group from high-reactivity types (carboxylic acid, sulfonic acid) to phosphonic acid groups. This parameter change maintains the self-dispersible pigment's ability to provide good color developability while significantly reducing reactivity to calcium ions, thereby preventing ink aggregation during recovery operations.
Solution Approach 2:
The patent uses composite self-dispersible pigments that combine phosphonic acid groups with other functional groups (such as hydroxyl, carboxyl, or sulfonic acid groups). This composite structure allows the pigment to maintain both good color developability and reduced aggregation tendency by balancing multiple functional properties.
2Device complexity
If self-dispersible pigments are used to eliminate dispersant requirements, then ink formulation is simplified, but ink aggregation during recovery operations occurs
Solution Approach 1:
The patent modifies the chemical structure parameter of the self-dispersible pigment by introducing phosphonic acid groups, which have lower reactivity to calcium ions compared to traditional carboxylic or sulfonic acid groups. This parameter change eliminates the need for additional dispersants while preventing ink aggregation during recovery operations.
Solution Approach 2:
The patent converts the potential harm of high reactivity to calcium ions (which causes aggregation) into a benefit by selecting phosphonic acid groups that have moderate reactivity. This allows the pigment to maintain self-dispersibility without causing aggregation, turning a previously harmful property into a controlled, beneficial characteristic.
3Reliability
If recovery operations are conducted to maintain recording head performance, then recording reliability is improved, but deposited aggregates cause irregular ejection
Solution Approach 1:
The patent changes the chemical reactivity parameter of the pigment by using phosphonic acid groups instead of highly reactive carboxylic or sulfonic acid groups. This parameter change prevents aggregation during recovery operations, allowing recovery to be conducted without causing irregular ejection or deposition on the recording head.
Solution Approach 2:
The patent provides beforehand cushioning by selecting phosphonic acid-based self-dispersible pigments that inherently resist aggregation. This preventive measure cushions against the harmful effects of recovery operations, ensuring that aggregate deposition and irregular ejection do not occur during or after recovery processes.
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 set effectively inhibits unnecessary ink aggregation during recovery operations, ensuring stable ejection and enhanced color developability of recorded images.
Implementation Method 1
a first self-dispersible pigment having a functional group that contains a phosphonic acid group and another atomic group and is bonded to a particle surface of the pigment
Implementation Method 2
having a functional group that contains a phosphonic acid group and another atomic group and is bonded to a particle surface of the pigment
Implementation Method 3
a second self-dispersible pigment having a functional group that contains at least one of a sulfonic acid group and a carboxylic acid group and is bonded to a particle surface of the pigment
Data Source
AI summary
An ink jet ink set including three aqueous inks of a cyan ink, a magenta ink and a yellow ink, wherein any two inks of the cyan ink, the magenta ink and the yellow ink are inks satisfying the following condition A, and the other ink is an ink satisfying the following condition B:Condition A: an ink containing a first self-dispersible pigment having a functional group that contains a phosphonic acid group and another atomic group and is bonded to a particle surface of the pigment; andCondition B: an ink containing a second self-dispersible pigment having a functional group that contains at least one of a sulfonic acid group and a carboxylic acid group and is bonded to a particle surface of the pigment.