Ink Set with Surfactant and Aggregating Compound for Water-Repellent Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ink sets face challenges in forming high-quality images on substrates with high water repellency, leading to decreased image density and striped unevenness due to poor wetting properties and excessive droplet size variation, while those with high surfactant content suffer from droplet interference and graininess.
Innovation Solution
An ink set comprising an ink composition with resin particles, a colorant, and water, along with a treatment solution containing an anionic surfactant and a compound to aggregate the colorant or resin particles, where the anionic surfactant has a hydrocarbon group with 6 or more carbon atoms, and the surfactant-to-aggregating compound ratio is between 0.001 and 0.600, enhancing wetting and droplet coalescence to improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a treatment solution with high surfactant content is used to improve permeability on water-repellent substrates, then wetting property improves, but liquid droplets spread excessively and interfere with each other causing graininess
Solution Approach 1:
The patent optimizes the surfactant concentration parameter to a specific range (0.01-5% by mass) and controls the ratio between surfactant and aggregating compound (0.001-0.600 by mass) to achieve balanced wetting without excessive droplet spread. This parameter optimization resolves the contradiction by finding the precise concentration range where wetting improvement occurs without triggering droplet interference and graininess.
2Measurement precision
If the ink droplet size is reduced to improve resolution, then image detail improves, but image density decreases due to insufficient ink coverage
Solution Approach 1:
The treatment solution is applied in advance to the substrate before ink ejection, modifying the substrate surface properties to enhance wetting and ink reception. This preliminary action allows smaller ink droplets to spread more effectively and coalesce properly on the treated surface, maintaining both high resolution and sufficient image density without requiring larger droplet sizes.
Solution Approach 2:
The treatment solution acts as an intermediary between the water-repellent substrate and the ink droplets, facilitating better interaction. The surfactant and aggregating compound in the treatment solution modify the substrate surface to improve ink wetting and promote controlled droplet coalescence, enabling small droplets to achieve adequate coverage and density while maintaining resolution.
3Manufacturing precision
If a compound to aggregate colorant or resin particles is added to suppress graininess, then image uniformity improves, but droplet coalescence is inhibited leading to decreased image density
Solution Approach 1:
The patent optimizes the concentration of the aggregating compound and controls its ratio to the surfactant (0.001-0.600 by mass) to achieve the right balance. This parameter control allows the aggregating compound to suppress graininess by controlling particle aggregation while the surfactant promotes droplet coalescence, resolving the contradiction between image uniformity and image density.
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 suppresses density decrease, striped unevenness, and graininess by improving substrate wetting and droplet size consistency, resulting in high-density, uniform images on substrates with high water repellency.
Implementation Method 1
a treatment solution including an anionic surfactant, water, and a compound configured to aggregate at least one of the colorant or the resin particles in the ink composition
Implementation Method 2
the substrate surface has a low wetting property with water
Implementation Method 3
a compound configured to aggregate at least one of the colorant or the resin particles in the ink composition
Data Source
AI summary
An ink set including an ink composition including resin particles, a colorant, and water, and a treatment solution including an anionic surfactant, water, and a compound configured to aggregate at least one of the colorant or the resin particles in the ink composition, in which the ratio of the content of the anionic surfactant with respect to the content of the compound configured to aggregate at least one of the colorant or the resin particles is 0.001 to 0.600 in terms of mass. An image forming method in which the ink set is used.