Active Ray-Curable Ink Sol-Gel Phase Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Actinic energy radiation curable inkjet systems face issues with image quality due to dot coalescence and color mixture, particularly when using ultraviolet radiation curable inks, leading to inferior glossiness and unnatural image appearance, especially on non-absorptive and slightly absorptive recording media.
Innovation Solution
An actinic energy radiation curable inkjet recording method utilizing an ink with a gelling agent that undergoes reversible sol/gel phase transition, controlling the storage elastic modulus and temperature to prevent dot coalescence, ensuring the ink remains fluid at high temperatures for smooth ejection and solidifies promptly upon deposition, thereby maintaining natural glossiness and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultraviolet radiation curable ink is used for high speed recording, then productivity is improved, but dot coalescence occurs causing inferior image quality
Solution Approach 1:
The patent applies phase transition by utilizing the sol-gel transition of the ink composition. The ink is maintained in a sol state (liquid) at high temperature during ejection for fast recording, then transitions to gel state (semi-solid) upon cooling on the substrate, preventing dot coalescence while maintaining high productivity
Solution Approach 2:
The patent changes physical parameters of the ink, specifically temperature and viscosity. By controlling the ink temperature above the gelation temperature during ejection and allowing it to cool below the gelation temperature on the substrate, the ink transitions from low viscosity (fluid) to high viscosity (gel) state, preventing dot collapse while enabling high-speed recording
2Manufacturing precision
If gelling agent is added to prevent dot coalescence, then image quality is improved, but glossiness decreases and unnatural glitter appears
Solution Approach 1:
The patent precisely controls the gelation temperature parameter and the temperature difference between ejection and substrate. By optimizing these parameters, the ink gels at the right moment to prevent coalescence but maintains sufficient fluidity and surface smoothness to preserve natural glossiness without unnatural glitter
Solution Approach 2:
The patent creates a dynamic system where the ink's physical state changes over time and temperature. The ink is fluid during ejection, transitions to gel on the substrate to prevent coalescence, but the gelation is controlled to maintain surface smoothness for natural glossiness
3Stability of the object's composition
If recording temperature is lowered to prevent coalescence, then dot stability is improved, but color mixture occurs between adjacent dots
Solution Approach 1:
The patent uses phase transition from sol to gel state to stabilize dots. The ink remains in sol state (liquid) at ejection temperature allowing proper dot placement and color separation, then transitions to gel state upon cooling to prevent dot coalescence and maintain dot stability
Solution Approach 2:
The patent performs preliminary heating of the ink to maintain it in sol state during ejection, ensuring proper dot formation and color separation before the ink cools and gels on the substrate to prevent coalescence
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 method achieves high fineness and natural glossiness on various recording media by controlling the solidification strength and viscosity of the ink droplets, preventing dot collapse and maintaining image quality without deterioration.
Implementation Method 1
an ink with a gelling agent that undergoes reversible sol/gel phase transition
Implementation Method 2
solidified an ink droplet simultaneously with the deposition of the droplet, resulted in preventing the coalescence of ink droplets
Implementation Method 3
actinic energy radiation curable composition which can be cured by the activity energy radiation such as ultraviolet radiation
Data Source
Figure 1~2
Figure 3~4b
Figure 5
AI summary
Provided are an active ray-curable ink, which can achieve a high fineness and natural glossiness when recording is carried out onto a non-absorptive recording medium such as a film or a laminated paper or a slightly absorptive recording medium such as a coated paper; and an active ray-curable inkjet recording method. This active ray-curable ink, which is to be used in inkjet recording, is characterized by: said active ray-curable ink undergoing reversible sol/gel phase transition depending on temperature; said active ray-curable ink containing from 1 mass% inclusive to 10 mass% exclusive of a gelling agent; and, at temperature Tm (°C) that is separately defined, the storage modulus (G) of the active ray-curable ink being from 0.1 Pa inclusive to 1000 Pa exclusive and the storage modulus (G') being smaller than the loss modulus (G") thereof.