UV Clear Ink Fills Non-Colored Regions to Level Print Surface
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Solution Overview
Problem
Ink jet printers face issues with the formation of uneven overcoat layers due to irregularities in the print surface caused by colored ink application, leading to transverse streaks, cracks, and air bubbles, which degrade the quality of printed matter.
Innovation Solution
The method involves using a UV clear ink to fill the non-colored regions on the print surface, applying it after the colored ink has been cured, and controlling the ink layer thickness to ensure evenness, with the UV clear ink being cured either matte or glossy depending on the printing step, and using a gray-scaled or inverted image to adjust ink droplet discharge based on gradations in the print image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a colored ink is applied to print an image, then the image is formed on the medium, but the print surface develops irregularity between colored ink-applied region and colored ink-unapplied region
Solution Approach 1:
The patent applies a clear coating layer selectively to the colored ink-unapplied regions to fill surface irregularities locally, while maintaining the colored image regions as they are. This local differentiation resolves the surface uniformity issue without affecting the image quality.
Solution Approach 2:
The clear coating layer acts as an intermediary substance that fills the gaps and irregularities between colored ink-applied and colored ink-unapplied regions, creating a uniform base surface for subsequent overcoat layer formation.
2Shape
If UV clear ink is applied to fill non-colored regions, then surface irregularity is suppressed, but the ink may flow out before curing if the base has irregularity
Solution Approach 1:
The patent performs preliminary surface preparation by applying a clear coating layer to fill irregularities before applying the UV clear ink. This preliminary action ensures the base surface is smooth and ready to receive the UV clear ink without causing it to flow out or create unevenness.
3Device complexity
If the overcoat layer is formed without filling non-colored regions, then the printing process is simpler, but transverse streaks and unevenness appear in the cured overcoat layer
Solution Approach 1:
The patent segments the printing process into distinct stages: first applying the clear coating layer to non-colored regions, then applying the UV clear ink, and finally forming the overcoat layer. This segmentation allows each step to be optimized independently, achieving uniform overcoat layer formation without excessive complexity.
4Manufacturing precision
If colored ink is applied first for image printing, then the image is created, but irregularity in the base surface causes the UV clear ink to spread unequally
Solution Approach 1:
The clear coating layer serves as an intermediary between the colored ink layer and the UV clear ink layer. It fills the irregularities introduced by the colored ink application, creating a uniform base that ensures the UV clear ink spreads evenly without compromising the underlying 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 effectively suppresses irregularity between colored ink-applied and non-applied regions, preventing unevenness in the overcoat layer and enhancing the quality of printed matter by ensuring a smooth, even surface for the overcoat layer.
Implementation Method 1
Inks most typically used in the ink jet printers are inks of ultraviolet curing type curable by being irradiated with ultraviolet light
Data Source
AI summary
When an image is printed by inkjet printing on a print surface of a target medium, an overcoat layer is formed in a more appropriate manner. A printing method uses color ink heads 202 as exemplified colored ink heads, a clear ink head 204, and ultraviolet irradiators 206. The printing method includes a color printing step of printing a print image using a colored ink in at least a partial region on a print surface of a medium 50, a non-colored region clear printing step of applying a UV clear ink for printing in a region at least including a non-colored region in which ink droplets are not discharged in the color printing step, and an overcoat layer forming step of forming an overcoat layer that covers the print image using the UV clear ink in a region covering at least the print image printed in the color printing step.