Ink Formulation with Segmented Resins for Fixability
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Solution Overview
Problem
Inkjet inks struggle with poor fixability on low- or non-absorbable print media due to inadequate drying, and increasing resin content improves fixability but compromises storage stability, especially at high temperatures.
Innovation Solution
An ink formulation with a specific ratio of resins having different glass transition temperatures (Tg) and the inclusion of a silicone-based surfactant, which balances tack force between 6 gf and 13 gf at 100°C, ensuring both storage stability and fixability, even with low-drying-power methods like UV drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resin content in the ink is increased to improve fixability on low- or non-absorbable print media, then the ink achieves better adhesion and drying, but the storage stability deteriorates and the ink thickens when stored at temperatures above the glass transition temperature of the resins
Solution Approach 1:
The resin component is segmented into multiple types with different glass transition temperatures. The ink contains a first resin with Tg of 50°C or higher and a second resin with Tg of -50°C to 49°C, creating a distributed resin system that provides fixability at operating temperatures while maintaining storage stability through the presence of lower-Tg resins that remain flexible during storage.
Solution Approach 2:
The ink employs a composite resin system combining organic resins and inorganic resins in specific weight ratios (organic resin 70-95 wt%, inorganic resin 5-30 wt%). This composite approach leverages the adhesion benefits of organic resins while the inorganic resins contribute to durability and controlled rheology, achieving both fixability and storage stability.
2Force
If the resin content is increased to ensure adequate tack force for fixability, then the ink adheres better to the print media, but the ink becomes prone to thickening and degradation during storage
Solution Approach 1:
The invention changes the parameter distribution of resin glass transition temperatures rather than simply increasing total resin content. By specifying that the first resin has Tg ≥50°C and the second resin has Tg between -50°C and 49°C, the system achieves adequate tack force at printing temperatures while the lower-Tg second resin prevents thickening during storage by maintaining molecular mobility.
Solution Approach 2:
Different resin components perform different local functions: the first resin (higher Tg) provides the primary tack force and adhesion to the print media, while the second resin (lower Tg) locally maintains fluidity and prevents aggregation during storage. This functional differentiation within the resin system resolves the contradiction between tack force and storage stability.
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 achieves a balance between storage stability and fixability, maintaining tack force within the desired range and preventing curling of print media, while allowing for effective drying without degrading storage properties.
Implementation Method 1
an image formed with the ink on a print medium has a tack force of 6 gf or greater but 13 gf or less when measured at a probe temperature of 100 degrees C., where the image is a solid image formed at a resolution of 1,200 dpi, subsequently irradiated with light of 395 nm for 0.6 seconds
Data Source
AI summary
An ink including a pigment, water, and a resin is provided. An image formed with the ink on a print medium has a tack force of 6 gf or greater but 13 gf or less when measured at a probe temperature of 100 degrees C., where the image is a solid image formed at a resolution of 1,200 dpi, subsequently irradiated with light of 395 nm for 0.6 seconds, and left to stand at normal temperatures and normal humidities for 30 seconds.