UV Curable Ink Viscosity Control for Print Surface Smoothness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inkjet printing with UV curable ink faces challenges in achieving smoothness and high image quality due to the inherent unevenness of the ink layer surface and the trade-off between improving smoothness and image quality, with existing solutions either leading to curing defects or increasing equipment costs and power consumption.
Innovation Solution
The use of a UV curable ink composition containing a thixotropy-imparting agent, such as silica, which has a low viscosity for ejection and increases to at least 80 mPa·s within five seconds of landing on the print medium, allowing for flattening without color mixing and improved surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the ink retains fluidity after landing for a longer period of time to improve smoothness, then the smoothness of the ink layer surface is improved, but the image quality deteriorates due to interference in the ink landing and mixing of the ink colors
Solution Approach 1:
The ink composition dynamically changes its viscosity over time after landing. Initially, the ink maintains low viscosity to allow flattening and improve smoothness, then progressively increases viscosity to prevent color mixing while maintaining image quality. This time-dependent viscosity change resolves the contradiction between smoothness and image quality.
Solution Approach 2:
The patent changes the viscosity parameter of the ink over time through specific composition design. The ink starts with low viscosity for flattening, then increases to higher viscosity to prevent color mixing. This parameter change over time allows both smoothness improvement and image quality maintenance.
2Shape
If a gelling agent is added to UV curable ink and the ink is heated to lower viscosity for ejection then quickly cooled to increase viscosity, then smoothness and image quality are improved, but a large heating mechanism is needed at the periphery of the head and in the ink flow channel, raising equipment costs and power consumption
Solution Approach 1:
The patent removes the external heating mechanism from the system by incorporating temperature-dependent viscosity control directly into the ink composition itself. The ink naturally adjusts its viscosity based on temperature without requiring external heating devices, thereby eliminating the associated power consumption and equipment costs.
Solution Approach 2:
The ink composition self-regulates its viscosity through temperature changes during the printing process. The ink naturally heats up during ejection and cooling occurs after landing, and the viscosity adjusts accordingly without external intervention. This self-service mechanism eliminates the need for power-consuming heating systems.
3Productivity
If UV curable ink is used for printing, then high-speed production and small installation space are achieved, but the printing face has poor smoothness and is generally matte due to large unevenness of the ejected ink
Solution Approach 1:
The patent changes the viscosity parameter of UV curable ink over time after ejection. The ink starts with low viscosity to allow flattening and improve smoothness, then increases viscosity to maintain image quality. This time-dependent parameter change enables both high-speed printing and smooth printing face.
Solution Approach 2:
The patent uses a composite ink composition containing multiple components including polymerizable compounds, photopolymerization initiators, and viscosity modifiers. This composite formulation enables the ink to exhibit time-dependent viscosity changes, allowing both high-speed printing and smooth surface finish.
4Shape
If the timing of ultraviolet light irradiation is delayed for flattening on bent surface portions, then smoothness may be improved, but dripping occurs and a favorable image cannot be obtained
Solution Approach 1:
The ink composition dynamically adjusts its viscosity in response to temperature changes and time elapsed since ejection. This dynamic viscosity change allows the ink to maintain appropriate fluidity for flattening on bent surfaces while preventing dripping and maintaining image quality.
Solution Approach 2:
The patent changes the viscosity parameter of the ink over time and temperature. The ink naturally increases viscosity as it cools and ages, providing self-regulation that prevents dripping while allowing sufficient time for flattening on bent surfaces without compromising 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
This approach enables both the flattening of the ink layer surface and high image quality without color mixing, even on curved surfaces, while reducing the occurrence of silver rings and drips, thus enhancing the overall printing process.
Implementation Method 1
a UV curable ink composition containing a thixotropy-imparting agent, such as silica, which has a low viscosity for ejection and increases to at least 80 mPa·s within five seconds of landing on the print medium
Implementation Method 2
An inkjet printing apparatus that prints by ejecting UV curable ink that is cured by emitting ultraviolet light
Data Source
AI summary
To provide an inkjet printing apparatus that improves the smoothness of the ink layer surface and improves the image quality. Provided is an inkjet printing apparatus that prints with a UV curable ink, the inkjet printing apparatus including: an ejection unit configured to eject the UV curable ink onto the surface of a print medium; and a control unit configured to control the ejection of the UV curable ink from the ejection unit, the UV curable ink containing a thixotropy-imparting agent, and the control unit setting the viscosity of the UV curable ink to 1 mPa·s to 20 mPa·s at the time of ejection and to at least 80 mPa·s within five seconds of landing on the print medium.