Aqueous Ink Jet Composition Conductivity Control for Fine Line Printing
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Solution Overview
Problem
Existing aqueous ink jet ink compositions face challenges in achieving storage stability and maintaining printing quality, especially when used on low ink-absorbing recording media, due to issues with ink permeability, affinity, and bleeding.
Innovation Solution
An aqueous ink jet ink composition with a surface-treated pigment having a phosphorus-containing group and a resin dispersion, where the conductivity is maintained within a specific range (2600 μs/cm or less), along with a reaction liquid containing an aggregating agent, is used to enhance storage stability and printing quality by improving ink permeability and affinity with the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pigment with surface modified with phosphorus-containing group is used to improve ink permeability and affinity, then printing quality during fine line printing is improved, but storage stability of the ink deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the conductivity of the ink composition within a specific range (2000 μS/cm or less, preferably 500-1500 μS/cm). This conductivity control is achieved by adjusting the phosphorus-containing group content on the pigment surface and optimizing the resin dispersion characteristics. By changing the electrical conductivity parameter, the patent resolves the contradiction between improved printing quality (through adequate phosphorus modification) and storage stability (through controlled conductivity), preventing pigment aggregation while maintaining fine line printing capability.
2Reliability
If conductivity of ink composition is increased to improve ejection reliability, then ink droplet ejection is improved, but storage stability deteriorates due to increased pigment aggregation
Solution Approach 1:
The patent optimizes the conductivity parameter to a specific range (2000 μS/cm or less, preferably 500-1500 μS/cm) that balances ejection reliability and storage stability. This parameter optimization prevents excessive pigment aggregation while ensuring adequate ejection performance through controlled electrical properties of the ink composition.
Solution Approach 2:
The patent employs composite materials by combining surface-treated pigment particles with phosphorus-containing groups and resin dispersion in a specific composition ratio. This composite structure provides both the surface activity needed for ejection reliability and the colloidal stability required for storage stability, resolving the contradiction between these two properties.
3Manufacturing precision
If phosphorus-containing group content on pigment surface is increased to improve ink affinity with recording medium, then image quality is improved, but ink composition becomes less stable due to increased conductivity
Solution Approach 1:
The patent controls the phosphorus-containing group content on the pigment surface by adjusting the conductivity parameter (2000 μS/cm or less). This parameter control optimizes the balance between ink affinity (improved by phosphorus groups) and composition stability (maintained through controlled conductivity), preventing excessive aggregation while ensuring good image quality.
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 solution provides an ink composition with excellent storage stability and printing quality during fine line printing, suppressing bleeding and ensuring ejection reliability, while maintaining abrasion resistance and image quality on various recording media.
Implementation Method 1
a pigment dispersion formed of a surface-treated pigment having a phosphorus-containing group on a surface thereof
Implementation Method 2
a reaction liquid containing an aggregating agent for aggregating components of the aqueous ink jet ink composition
Data Source
AI summary
The aqueous ink jet ink composition contains a pigment dispersion formed of a surface-treated pigment having a phosphorus-containing group on a surface thereof and a resin dispersion, in which a conductivity of the ink composition is 2600 μs/cm or less.