Inkjet Recording Method Using Active Light-Curable Ink
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional UV-curable inkjet recording methods face issues with image quality due to dot combining and blooming phenomena, particularly when using gelling agents, which affect the glossiness and density of printed matter over time.
Innovation Solution
An inkjet recording process that involves landing actinic radiation-curable inkjet ink containing a gelling agent, photocurable compound, and photopolymerization initiator, with specific temperature control to maintain leveling and pinning properties while preventing blooming, by ensuring the gelation temperature is higher than the ink temperatures at landing and irradiation, and solubility of the gelling agent is less than 0.1% at the irradiation temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the ink temperature is raised to improve the leveling property, then the leveling property is improved, but combining of dots (liquid gathering) occurs due to lowering of the pinning property
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ink temperature within a specific range (20°C to 35°C) to optimize both leveling property and pinning property. This temperature parameter control prevents dot combining while maintaining adequate leveling, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent introduces a gelling agent that creates local gel structure formation at the ink-substrate interface, providing enhanced pinning effect in specific regions where needed. This local quality change allows the ink to maintain pinning property at dot boundaries while still achieving leveling within each dot area.
2Manufacturing precision
If a gelling agent is added to prevent combining of neighboring dots, then dot combining is prevented, but blooming phenomenon occurs affecting glossiness and density
Solution Approach 1:
The patent uses a composite material approach by combining the gelling agent with a specific solvent system (carboxylic acid and its ester). This composite formulation allows the gelling agent to provide pinning effect while the solvent system controls the gelation kinetics and prevents excessive blooming, achieving both dot separation and image quality.
Solution Approach 2:
The patent applies dynamics by controlling the gelation process to occur at a specific rate and timing. The gelation is not instantaneous but progresses dynamically after ink ejection, allowing the ink to first level within dots then gel to prevent blooming. This dynamic control resolves the contradiction between preventing dot combining and preventing blooming.
3Productivity
If high-speed recording is performed, then productivity is improved, but image quality deteriorates due to dot combining
Solution Approach 1:
The patent applies preliminary action by pre-formulating the ink with a gelling agent and solvent system that will automatically gel after ejection. This preliminary preparation ensures that the ink has built-in pinning capability that activates rapidly after deposition, allowing high-speed recording without dot combining while maintaining image quality.
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 process effectively prevents blooming and maintains image quality by controlling ink temperatures and solubility, allowing for curing with a small light energy dose and minimizing defects in the printed matter.
Implementation Method 1
the ink viscosity rapidly increases by sol-gel phase transition after the ink is landed (pinning effect)
Implementation Method 2
forming an image by discharging an actinic radiation-curable ink onto a recording medium; irradiating the image formed on the recording medium with actinic radiation
Implementation Method 3
polymerization reaction on the surface of an ink film is inhibited by oxygen
Data Source
AI summary
An inkjet recording method using an active light-curable inkjet ink according to the present invention is characterized in that: the inkjet ink contains at least a gelling agent, a photopolymerizable compound and a photopolymerization initiator; the gelling temperature T1 (° C.) of the active light-curable inkjet ink, the temperature T2 (° C.) of the ink at the time when the active light-curable inkjet ink landed on a recording medium, and the temperature T3 (° C.) of the ink at the time when the active light-curable inkjet ink is irradiated with active light satisfy the relationship T1 (° C.)>T2 (° C.)>T3 (° C.); and the solubility of the gelling agent in the photopolymerizable compound at T3 (° C.) is less than 0.1% by mass. This inkjet recording method is capable of suppressing blooming, while at least maintaining the leveling properties and the pinning properties of an inkjet ink.