UV-Curable Ink Jet Nozzle Cleaning and Curing Stability
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Solution Overview
Problem
Ink jet recording methods face issues with bleeding, wrinkles, and streaks due to the influence of ultraviolet irradiation light sources on the head, leading to decreased discharge stability and storage stability of the ink composition, especially when using hindered amines as polymerization inhibitors.
Innovation Solution
An ink jet recording method involving the use of an ultraviolet-curable ink composition containing a color material, a polymerizable compound with di- or higher functional (meth)acryloyl groups, a photopolymerization initiator, and a hindered amine compound, where the ink is discharged and irradiated multiple times with controlled ultraviolet energy, and the nozzle is wiped using a cleaning liquid to improve cleaning resettability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultraviolet irradiation light source with strong irradiation energy is disposed around the head to improve curing efficiency, then the curing speed is improved, but the heat influence on the head increases causing discharge stability to deteriorate
Solution Approach 1:
The ink composition is segmented into multiple functional components with specific roles: polymerizable compounds for curing, hindered amine compounds for stability, and surfactants for discharge control. This segmentation allows each component to optimize its function while maintaining overall system balance between curing speed and discharge stability.
Solution Approach 2:
The patent specifies precise parameter ranges for each component: polymerizable compounds at 70-95 mass%, hindered amine compounds at 0.01-5 mass%, and surfactants at 0.1-10 mass%. These parameter changes ensure the ink composition achieves both rapid curing under UV irradiation and stable discharge from the head, resolving the contradiction between curing efficiency and discharge reliability.
2Reliability
If ultraviolet irradiation energy is decreased to reduce heat influence on the head, then discharge stability is improved, but wrinkles are generated on the ink composition when hindered amine is used
Solution Approach 1:
The hindered amine compound acts as an intermediary substance that mediates between the conflicting requirements of low UV energy (for discharge stability) and sufficient curing (for surface smoothness). This intermediary component enables the system to achieve both discharge stability and wrinkle-free surfaces by controlling the polymerization process at low irradiation energies.
Solution Approach 2:
The ink composition is a composite material combining polymerizable compounds, hindered amine compounds, and surfactants in specific ratios. This composite formulation allows the system to simultaneously achieve discharge stability, prevent wrinkles, and maintain storage stability, resolving the contradiction between discharge reliability and surface quality.
3Stability of the object's composition
If hindered amine compound is used as polymerization inhibitor to improve storage stability, then storage stability is improved, but wrinkles are generated when ultraviolet irradiation energy is low
Solution Approach 1:
The patent optimizes the concentration parameter of hindered amine compounds within 0.01-5 mass% to achieve the right balance between storage stability and surface smoothness. This parameter change allows the hindered amine to function effectively as a polymerization inhibitor during storage while preventing wrinkle formation during low-energy UV curing.
Solution Approach 2:
The composite ink composition combines hindered amine compounds with specific polymerizable compounds and surfactants in controlled ratios. This composite material approach ensures that the hindered amine provides storage stability without causing wrinkles during curing, as the other components compensate for potential surface defects.
4Manufacturing precision
If ink composition is discharged in order of increasing curability to suppress bleeding, then bleeding is suppressed, but cleaning resettability deteriorates due to cross-linked polymer formation on the head
Solution Approach 1:
The patent extracts the polymerization reaction from the discharge process by using hindered amine compounds as polymerization inhibitors. This extraction prevents premature cross-linking on the head surface, allowing the ink to be discharged without forming difficult-to-remove cross-linked polymers, thereby improving cleaning resettability while maintaining bleeding suppression.
Solution Approach 2:
The hindered amine compound serves as an intermediary that prevents premature polymerization during discharge and storage, but allows controlled polymerization during UV curing. This intermediary function enables the system to suppress bleeding through controlled curing sequences while preventing cross-linked polymer accumulation on the head that would hinder cleaning resettability.
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 effectively suppresses bleeding, wrinkles, and streaks while maintaining excellent storage stability and discharge stability, enhancing the overall performance of the ink jet recording process.
Implementation Method 1
an ink jet recording method of curing an ink composition by ultraviolet irradiation
Implementation Method 2
when an ink composition containing a hindered amine is used, there is a problem of generating wrinkles on the ink composition adhered to the recording medium. Meanwhile, when the ink composition does not contain a hindered amine as a polymerization inhibitor, there is also a problem of the storage stability of the ink composition markedly deteriorating.
Implementation Method 3
irradiating the ultraviolet-curable ink composition adhered to the recording medium with ultraviolet rays two times or more
Data Source
AI summary
Disclosed herein is an ink jet recording method, including: scanning a recording medium with an ink jet head and simultaneously discharging an ultraviolet-curable ink composition for ink jet recording from the ink jet head to adhere the ink composition to the recording medium; irradiating the ultraviolet-curable ink composition for ink jet recording adhered to the recording medium with ultraviolet rays two times or more; and wiping a nozzle of the ink jet head, from which the ultraviolet-curable ink composition for ink jet recording has been discharged, using a nozzle wiping member.