Patterned Clear Ink Layer for UV Print Gloss Banding
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Solution Overview
Problem
Ultraviolet inkjet printing systems face the issue of gloss banding, which results in undesirable matte surface structures and visible gloss variations, particularly in high gloss finishes, due to the curing of UV ink droplets leaving a matte surface, limiting the availability of high gloss finishes and impacting print quality and color gamut.
Innovation Solution
A system and method involving the application of a clear, low print-density after-layer of high gloss ink, using a modified printer carriage with additional print heads and curing lamps to apply and cure colored and clear ink layers, allowing for precise control of gloss without relying on gelling agents or variable cure patterns, thereby reducing or eliminating gloss banding while maintaining a large color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If UV ink droplets are cured to create high gloss finishes, then the print quality and color gamut are improved, but gloss banding artifacts appear due to the matte surface structure left by curing
Solution Approach 1:
A clear gloss control layer is applied as an intermediary between the colored ink layers and the viewer. This clear layer acts as a mediator that modifies the surface properties to reduce gloss banding while preserving the color gamut and print quality of the underlying colored inks.
Solution Approach 2:
The clear gloss control layer is applied in a patterned manner with varying densities across different regions of the print. By locally adjusting the density of the clear layer, the invention creates different gloss levels in different areas, thereby compensating for gloss banding artifacts in specific regions while maintaining high gloss where desired.
2Object-generated harmful factors
If large ink droplets are used to achieve a matte effect, then gloss banding is reduced, but print quality and color gamut deteriorate due to low DPI and inefficient pigment use
Solution Approach 1:
Instead of modifying the colored ink droplets to achieve matte effects (which degrades print quality), the invention inverts the approach by applying a separate clear gloss control layer on top of the colored inks. This clear layer is optimized for gloss control rather than color reproduction, allowing the colored inks to maintain high print quality while the clear layer manages the surface appearance.
3Object-generated harmful factors
If a patterned mask is used for variable cure to control gloss, then gloss variation is achieved, but the process complexity increases and requires gelling agents
Solution Approach 1:
The invention extracts the gloss control function from the curing process itself. Instead of using complex variable cure patterns and gelling agents to control gloss, the invention separates color deposition from gloss control by applying a dedicated clear gloss control layer that is cured uniformly, thereby simplifying the overall printing and curing process.
4Illumination intensity
If high gloss ink is applied to achieve high gloss finish, then the reflective intensity is improved, but gloss banding artifacts become more visible
Solution Approach 1:
The invention changes the parameters of the clear gloss control layer, specifically its density and opacity, to optimize gloss control. By adjusting these parameters, the clear layer can reduce the visibility of gloss banding while maintaining adequate gloss reflectivity, achieving a balance between the two competing requirements.
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 solution effectively minimizes gloss banding at high print speeds while preserving color gamut, allowing for controlled gloss levels and improved print quality by applying a clear ink layer in a preprogrammed pattern, which is cured simultaneously with the colored ink, resulting in a uniform, low gloss finish with reduced visibility of gloss differentials.
Implementation Method 1
The printer heads are coupled with a container containing ink. Ink is ejected from one or more nozzles of the print heads when a piezoelectric crystal in the print head is actuated. The piezoelectric crystal generates a pulse in the ink so that the ink expels through the nozzle as a droplet.
Implementation Method 2
The deposited ink is cured with a UV light source. The one or more curing lamps are associated with the modified carriage and configured to cure the deposited ink.
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
The invention involves application of a clear, low-density after-layer of high gloss ink onto a printed substrate to reduce or eliminate negative printing effects, such as gloss banding. Some embodiments of the invention involve a method of applying colored ink, curing the colored ink, applying a clear ink layer in a pattern, and curing the clear layer.