Ink Composition Thermo-Reversible Gelling for Print Quality
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Solution Overview
Problem
Inkjet printing technologies face issues with low viscosity inks causing show-through, bleeding, and unsharp images due to insufficient viscosity control, especially on porous and non-absorbing media, and polymeric gelling agents introduce unwanted rheological effects and increased viscosity, limiting design freedom and print quality.
Innovation Solution
An aqueous ink composition using a low molecular weight organic amine oxide as a gelling agent, with a molecular weight between 200 g/mol and 700 g/mol, which exhibits thermo-reversible gelling properties, allowing controlled viscosity increase with temperature changes, preventing spreading and absorption issues without significantly affecting ink properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a low viscosity ink is used, then the ink spreads quickly and absorbs well into the receiving medium, but the ink penetrates through porous media causing show-through and bleeding
Solution Approach 1:
The patent applies a viscosity-modifying agent that dynamically changes ink viscosity based on environmental conditions (temperature, humidity, substrate interaction). The agent remains dormant during jetting but activates after deposition, transforming the ink from low-viscosity (for fast spreading) to high-viscosity (for preventing show-through and bleeding), thus resolving the contradiction between spreading speed and image sharpness
Solution Approach 2:
The patent changes the viscosity parameter of the ink over time and space by incorporating a viscosity-modifying agent. The agent responds to triggers such as temperature change, humidity exposure, or substrate contact to increase viscosity after the ink is deposited, allowing the ink to spread initially then stabilize, preventing further unwanted flow that causes bleeding and show-through
2Manufacturing precision
If polymeric gelling agents are used to increase viscosity, then the ink shows improved spreading control, but the basic viscosity level increases limiting design freedom
Solution Approach 1:
The patent extracts the unwanted continuously high viscosity property from conventional polymeric gelling agents and replaces it with a triggered viscosity increase mechanism. The viscosity-modifying agent only activates under specific conditions after ink deposition, allowing the ink to maintain low basic viscosity for design freedom while providing spreading control only when needed, thus resolving the contradiction between spreading control and viscosity working range
Solution Approach 2:
The patent incorporates the viscosity-modifying agent into the ink formulation in advance, but the agent remains inactive during jetting and storage. The agent is designed to activate only after the ink is deposited on the substrate, providing spreading control at the right moment without affecting the ink's basic viscosity characteristics during handling and storage
3Manufacturing precision
If polymeric gelling agents are used, then the ink shows improved gelling properties, but unwanted non-linear rheological effects such as shear thinning and yield stress are introduced
Solution Approach 1:
The patent replaces complex polymeric gelling agents with a simpler viscosity-modifying agent that provides the necessary gelling control without introducing problematic rheological effects. The agent is designed to provide linear, predictable viscosity changes that maintain stable ink flow through the printing system while still achieving the desired gelling control after deposition, thus resolving the contradiction between gelling control and ink supply reliability
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 composition effectively controls viscosity and prevents print artifacts like feathering, show-through, and bleeding, enhancing print quality and productivity while maintaining design flexibility, suitable for various substrates and printing methods.
Implementation Method 1
the ink composition has thermo-reversible gelling properties and has a low viscosity at jetting conditions
Implementation Method 2
it is generally known that viscosity of a liquid system depends on temperature, in particular that the viscosity increases with decreasing temperature
Data Source
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Figure 3~4
Figure 5A~7B
AI summary
The present invention relates to an aqueous ink composition comprising a low molecular weight gelling agent, for example an organic amineoxide, in particular octadecyldimethylamine oxide. The invention further relates to a method of printing such an ink composition.