Ink Set Polymer Ratios for Uniform Aggregation and Bleeding Control
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Solution Overview
Problem
Existing ink jet recording methods often result in uneven ink distribution and 'bleeding' due to the aggregation of resin fine particles in aqueous ink compositions, leading to grainy or streaky defects in images.
Innovation Solution
An ink set comprising an ink composition with a specific ratio of water-soluble polymer B to pigment dispersion polymer A, along with a treatment liquid containing a polyvalent metal salt, acidic compound, or cationic polymer, which promotes uniform aggregation and thickening of the ink, reducing bleeding and image cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a treatment agent is used to aggregate resin fine particles in aqueous ink composition, then image recording speed and definition are improved, but uniform aggregation is not achieved leading to grainy or streaky defects
Solution Approach 1:
The patent changes the chemical parameters of the ink composition by specifying precise ratios of water-soluble polymer to pigment dispersion polymer (1.6 or more by mass), and controlling the content of resin fine particles (0.1-10% by mass). These parameter adjustments enable uniform aggregation when treatment agent is applied, resolving the contradiction between fast recording and image uniformity.
Solution Approach 2:
The patent creates a composite ink composition system combining multiple components: pigment dispersion polymer A, water-soluble polymer B, and resin fine particles in specific ratios. This composite structure ensures that when treatment agent is applied, all components aggregate uniformly together, preventing grainy or streaky defects while maintaining high recording speed.
2Measurement precision
If resin fine particles are aggregated in the ink composition, then higher-definition images are recorded, but bleeding and image cracking occur
Solution Approach 1:
The patent controls the content of resin fine particles within a specific range (0.1-10% by mass) and maintains a minimum ratio of water-soluble polymer to pigment dispersion polymer (1.6 or more by mass). These parameter changes ensure sufficient aggregation for high definition while preventing excessive aggregation that causes bleeding and cracking.
Solution Approach 2:
The water-soluble polymer B acts as an intermediary substance that mediates between pigment dispersion polymer A and resin fine particles. This intermediary ensures uniform distribution and controlled aggregation, achieving high definition images without bleeding or cracking by preventing direct excessive interaction between pigment and resin particles.
3Manufacturing precision
If the ratio of water-soluble polymer to pigment dispersion polymer is increased, then bleeding is suppressed, but ink jettability may be affected
Solution Approach 1:
The patent optimizes the ratio of water-soluble polymer to pigment dispersion polymer at 1.6 or more by mass, and controls resin fine particle content at 0.1-10% by mass. These parameter changes suppress bleeding through uniform aggregation while maintaining appropriate ink viscosity and flow properties for good jettability.
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 proposed ink set effectively suppresses bleeding and image cracking, enhancing image quality by ensuring uniform ink distribution and density, while maintaining the jettability of the ink composition.
Implementation Method 1
a treatment liquid that contains water and at least one selected from the group consisting of a polyvalent metal salt, an acidic compound, and a cationic polymer
Implementation Method 2
a treatment liquid that contains water and at least one selected from the group consisting of a polyvalent metal salt, an acidic compound, and a cationic polymer
Implementation Method 3
promotes uniform aggregation and thickening of the ink, reducing bleeding and image cracking
Data Source
AI summary
An ink set including an ink containing water, a pigment, a pigment dispersion polymer A, and a water-soluble polymer B, and a treatment liquid containing water and at least one selected from the group consisting of a polyvalent metal salt, an acidic compound, and a cationic polymer, in which the pigment dispersion polymer A contains a specific acid group and an aromatic ring, and the water-soluble polymer B contains a specific acid group and a constitutional unit represented by General Formula (1), and in the ink, a mass ratio of a content concentration of the water-soluble polymer B to a content concentration of the pigment dispersion polymer A in a liberated polymer is 1.6 or more, and an image recording method. R1 represents a hydrogen atom or a monovalent substituent, Y1 represents a monovalent substituent, A1 represents —O—, and L1 is a divalent linking group.