Clear Ink Application Control for Print Gloss Uniformity
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Solution Overview
Problem
Existing technologies fail to effectively suppress uneven glossiness in printed images when using clear ink across areas with predominantly light inks and dark inks, as they either adjust glossiness based on colored ink amounts or differentiate clear ink usage by printing modes, but not both simultaneously.
Innovation Solution
An image processing apparatus and method that determines and controls the application amounts of colored inks and clear ink using a print head, where the clear ink is applied before or after the colored ink, based on image data, to adjust glossiness between light and dark ink areas, ensuring the first application amount of clear ink is greater than the second in certain cases, and vice versa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clear ink is applied uniformly across all areas regardless of ink type, then the printing process is simple, but uneven glossiness occurs between light and dark ink areas
Solution Approach 1:
The patent applies different clear ink application strategies to different regions: in light ink areas, clear ink is applied before colored ink to enhance glossiness, while in dark ink areas, clear ink is applied after colored ink to minimize glossiness enhancement. This local differentiation resolves the contradiction by adapting the clear ink application timing and amount to the specific regional characteristics, achieving uniform glossiness across the entire image while maintaining operational simplicity through automated region-based control.
2Illumination intensity
If clear ink application amount is increased in light ink areas, then glossiness is enhanced, but glossiness becomes too strong and unnatural
Solution Approach 1:
The patent dynamically changes the clear ink application parameters based on the local ink characteristics: in light ink areas, clear ink is applied before colored ink with controlled amounts to provide moderate gloss enhancement, while in dark ink areas, clear ink is applied after colored ink with reduced amounts to prevent excessive glossiness. This parameter adaptation ensures that glossiness remains natural and visually pleasing across different regions without appearing overly strong or artificial.
3Illumination intensity
If clear ink is applied before colored ink, then glossiness is enhanced in light areas, but color density may be affected
Solution Approach 1:
The patent applies clear ink before colored ink selectively only in light ink areas where glossiness enhancement is desired, while in dark ink areas, clear ink is applied after colored ink to preserve color density. This spatial differentiation ensures that color density accuracy is maintained in critical dark regions while still achieving glossiness enhancement in light regions, resolving the contradiction between glossiness enhancement and color density reliability.
Data Source
AI summary
Uneven glossiness is effectively suppressed between areas where light inks are mainly used and areas where dark inks are mainly used. The gloss is raised in areas where dark cyan ink C is used. In other words, the application amount of second clear ink applied by after application printing is set to 32% at primary cyan (grid point 16) to equalize the gloss with areas where light cyan ink LC is used. Also, the application amount of first clear ink applied by common printing is set to 32% in a highlight portion (grid point 8) to equalize the gloss with the maximum gloss reached using dark cyan ink C. In so doing, it is possible to keep the gloss nearly constant over the entire range from white to cyan, or in other words, suppress uneven glossiness.