UV-Curing Metallic Ink Brightness via Particle Alignment
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Solution Overview
Problem
Ultraviolet curing type metallic inks fail to achieve sufficient brightness in printed materials, despite increased metal particle content, due to incomplete orientation and alignment of metal particles, leading to diffuse reflection and reduced brightness.
Innovation Solution
A printing method involving an ink ejection process with ultraviolet curing type metallic ink, followed by a leveling process using heat to align metal particles parallel to the recording medium, a temporary curing process to prevent excessive ink penetration, and a main curing process to achieve a thin ink layer and uniform particle alignment, thereby enhancing brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the content of metal particles is increased to improve brightness, then the brightness should be improved, but the brightness is not sufficiently improved because the metal particles are not properly aligned
Solution Approach 1:
The patent applies preliminary action by performing a leveling process before the main curing process. The leveling process aligns metal particles in scale shape to be parallel to the recording medium surface before UV curing fixes their positions. This preliminary alignment ensures that when more metal particles are added, they contribute effectively to brightness enhancement rather than causing diffuse reflection.
Solution Approach 2:
The patent changes the physical state parameters of the ink layer by controlling solvent penetration to achieve a thin ink layer thickness. This parameter change creates optimal conditions for metal particle alignment during the leveling process and ensures uniform UV curing, preventing curing shrinkage that would disrupt particle alignment and reduce brightness.
2Quantity of substance
If the ink layer thickness is increased to provide more metal particles for brightness, then more metal particles are available, but the metal particles cannot be properly aligned and curing shrinkage causes position displacement
Solution Approach 1:
The patent changes the parameter of ink layer thickness by controlling solvent penetration into the recording medium. A thin ink layer is formed to enable proper metal particle alignment while still providing sufficient particle quantity for brightness. The solvent penetration depth is controlled to achieve optimal thickness that balances particle quantity with alignment capability.
Solution Approach 2:
The leveling process is performed as a preliminary action before UV curing to align metal particles in the thin ink layer. This ensures that even with limited particle quantity in a thin layer, the particles are optimally oriented for maximum brightness, preventing the diffuse reflection that would occur with random orientation.
3Reliability
If ultraviolet rays are irradiated for complete curing to fix the ink, then the ink is fully cured, but curing shrinkage displaces metal particle positions and reduces brightness
Solution Approach 1:
The patent segments the UV curing process into two distinct stages: a leveling process and a main curing process. The leveling process performs partial curing with sufficient UV irradiation to begin fixation while maintaining conditions for particle alignment. The main curing process then completes the fixation. This segmentation prevents the single-step complete curing from causing excessive shrinkage that would displace aligned particles.
Solution Approach 2:
The leveling process serves as a preliminary curing action that partially fixes the ink while metal particles are still being aligned. This preliminary fixation prevents particles from moving during alignment while allowing the alignment process to occur, and avoids the shrinkage problems of complete one-step curing.
4Strength
If the ink is allowed to penetrate deeply into the recording medium to ensure adhesion, then adhesion is improved, but the ink layer thickness increases and prevents proper particle alignment
Solution Approach 1:
The patent changes the parameter of solvent penetration depth to achieve optimal balance between adhesion and particle alignment. The solvent penetrates sufficiently into the recording medium to ensure good adhesion of the ink layer, but the penetration depth is controlled to maintain a thin overall ink layer thickness that allows metal particles to align properly during the leveling process.
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 results in a printed material with improved brightness by ensuring uniform alignment and reduced curing shrinkage of metal particles, preventing discoloration and maintaining particle position, thus achieving higher reflectivity.
Implementation Method 1
a process in which the solvent of the ultraviolet curing type metallic ink is penetrated into the recording medium, thereby making the thickness of a formed ink layer thin
Implementation Method 2
a temporary curing process in which ultraviolet rays are irradiated to the metallic ink on the recording medium to cure in such a degree that the ink is not completely cured; and a main curing process in which ultraviolet rays are irradiated to the metallic ink on the recording medium for curing after the temporary curing process
Implementation Method 3
the leveling process is performed by heating the recording medium
Data Source
Figure 1~2
AI summary
The problem addressed by the present invention lies in obtaining printed material having higher brightness using an ultraviolet-curing metallic ink. In order to solve this problem, the printing method according to the present invention comprises the following steps : an ink discharge step in which an ultraviolet-curing metallic ink is discharged onto a recording medium which is readily penetrated by the metallic ink ; a levelling step for levelling the ink ; a temporary curing step in which ultraviolet rays are irradiated to the extent that the metallic ink is not completely cured ; and a full curing step in which ultraviolet rays are irradiated in order to cure the metallic ink.