pH-Responsive Ink Set for Uniform Aggregation
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Solution Overview
Problem
Current inkjet technologies face challenges in achieving high-quality, high-speed image printing with reduced ink bleeding and density non-uniformities, particularly in industrial settings, due to issues with ink aggregation and transfer characteristics in intermediate transfer systems.
Innovation Solution
An ink set comprising a first liquid with a coloring material and polymer particles dispersed in a water-based solvent, and a second liquid that changes the pH of the first liquid, where specific pH conditions ensure effective aggregation of the polymer particles before the coloring material, preventing ink bleeding and density non-uniformities, and enhancing transfer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If strong aggregating agents like polyvalent metal salts are used to increase aggregating force, then ink bleeding is reduced to some extent, but density non-uniformities occur in solid image regions and reaction non-uniformities arise
Solution Approach 1:
The patent introduces polymer particles as intermediary substances between the coloring material and the aggregating agent. These polymer particles first aggregate and then bind the coloring material, acting as a mediator that prevents direct strong interaction between the aggregating agent and coloring material, thereby avoiding excessive aggregation and ensuring uniform density distribution in solid image regions
Solution Approach 2:
The patent applies preliminary action by having the polymer particles aggregate before the coloring material. The polymer particles form aggregates first, and then the coloring material is incorporated into these pre-formed polymer aggregates. This sequence prevents the coloring material from aggregating too strongly with the aggregating agent, thereby preventing density non-uniformities while still achieving sufficient ink bleeding reduction
2Object-affected harmful factors
If aggregating force is increased to prevent ink bleeding, then image quality improves, but transfer non-uniformities and transfer defects occur in intermediate transfer systems
Solution Approach 1:
The polymer particles serve as intermediary substances that modulate the aggregating force. By binding the coloring material through the polymer aggregate structure, they provide sufficient aggregation to prevent ink bleeding while avoiding excessive aggregating force that would cause transfer non-uniformities and defects in intermediate transfer systems
Solution Approach 2:
The patent utilizes parameter changes by controlling the pH level to regulate the aggregating force. By adjusting pH parameters, the aggregation of polymer particles and coloring material is optimized to achieve the right balance: strong enough to prevent ink bleeding, but not so strong as to cause transfer defects
3Quantity of substance
If polyvalent metal salt is used as aggregating agent, then image density is improved, but reaction non-uniformities occur due to strong aggregating action at contact interface
Solution Approach 1:
The polymer particles act as intermediaries that distribute the aggregating action more uniformly. Instead of the polyvalent metal salt directly and strongly aggregating the coloring material at the contact interface, the polymer particles first aggregate and then bind the coloring material, spreading the aggregation process throughout the solution and ensuring uniform reaction progression
Solution Approach 2:
The polymer particles perform preliminary aggregation before the coloring material is fully aggregated. This preliminary action of polymer aggregation creates a distributed network that subsequently incorporates the coloring material uniformly, preventing the strong localized aggregation that occurs when polyvalent metal salts directly interact with the coloring material
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 achieves high-quality images with reduced ink bleeding and density non-uniformities, while improving fixing characteristics and preventing transfer defects, even with strong aggregating agents like polyvalent metal salts, by ensuring uniform aggregation and bonding of pigment and polymer particles.
Implementation Method 1
the polymer particles and the coloring material aggregate by means of a pH change
Implementation Method 2
a second liquid which changes pH of the first liquid
Implementation Method 3
the polymer having properties such that when dispersed in an aqueous polymer solution, a volume-average particle size of the polymer is changed along with a pH change of the aqueous polymer solution
Implementation Method 4
a first liquid which contains a coloring material, a polymer, and a dispersion medium composed of water and water-soluble solvent, the coloring material and the polymer being dispersed in the dispersion medium
Data Source
AI summary
The ink set includes: a first liquid which contains a coloring material, a polymer, and a dispersion medium composed of water and water-soluble solvent, the coloring material and the polymer being dispersed in the dispersion medium, the coloring material having properties such that when dispersed in an aqueous coloring material solution, a volume-average particle size of the coloring material is changed along with a pH change of the aqueous coloring material solution, the polymer having properties such that when dispersed in an aqueous polymer solution, a volume-average particle size of the polymer is changed along with a pH change of the aqueous polymer solution; and a second liquid which changes pH of the first liquid, wherein a condition of |α−β1|≧|α−β2| is satisfied, where α is pH of the first liquid before the first liquid is subjected to a pH change caused by the second liquid, β1 is pH of the aqueous coloring material solution at which the volume-average particle size of the coloring material reaches 1000 nm along with the pH change of the aqueous coloring material solution, and β2 is pH of the aqueous polymer solution at which the volume-average particle size of the polymer reaches 1000 nm along with the pH change of the aqueous polymer solution.