Printing Apparatus Ink Ejection Sequence Suppresses Bronze Phenomenon
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Solution Overview
Problem
Printing on glossy paper with high smoothness often results in the 'bronze phenomenon' where reflected light appears differently colored than the original pigment, and existing solutions require additional nozzles increasing manufacturing costs.
Innovation Solution
A printing apparatus with a first nozzle for dark black ink and a second nozzle for low-content black ink, where the second ink is ejected after the first ink to suppress the bronze phenomenon, allowing for a light black color expression without the need for a special clear ink nozzle, thus reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If clear ink is ejected separately from pigment ink to suppress bronze phenomenon, then the bronze phenomenon is suppressed, but the manufacturing cost increases due to requiring an exclusive nozzle
Solution Approach 1:
The patent makes the second nozzle serve multiple functions: it ejects low-concentration black ink to suppress the bronze phenomenon on glossy paper, and simultaneously ejects standard concentration black ink for normal printing operations. This multi-functionality eliminates the need for a separate clear ink nozzle, reducing manufacturing cost while maintaining the ability to suppress bronze phenomenon when needed.
Solution Approach 2:
The patent changes the concentration parameter of black ink in the second nozzle (making it lower than standard concentration) to enable bronze phenomenon suppression. By controlling the ink concentration ratio between first and second nozzles, the system can suppress bronze phenomenon without requiring a completely separate clear ink system, thus balancing performance improvement with cost control.
2Object-affected harmful factors
If second ink with low coloring material content is ejected after first ink to suppress bronze phenomenon, then the bronze phenomenon is suppressed and light black color is expressed, but the ink use rate must be precisely controlled
Solution Approach 1:
The patent implements feedback control by calculating the ink use rate of the second nozzle based on the total ink ejection amount and adjusting the second nozzle's operation accordingly. The control unit determines whether to activate the second nozzle based on the computed ink use rate, ensuring precise control over the bronze phenomenon suppression while maintaining simple operational logic.
3Illumination intensity
If the second ink is ejected to all pixels in unit area with high use rate, then darker black color is achieved, but the bronze phenomenon suppression effectiveness decreases
Solution Approach 1:
The patent optimizes the ink use rate parameter of the second nozzle to a specific range (1% to 15%) that balances two competing requirements: achieving sufficient black color depth while maintaining effective bronze phenomenon suppression. This parameter optimization allows the system to express darker black colors without sacrificing the anti-bronze effect, resolving the contradiction between color depth and phenomenon suppression.
Data Source
AI summary
A printing apparatus includes a first nozzle which ejects first ink containing a black coloring material, a second nozzle which ejects second ink with a low content rate of the coloring material compared to the first ink, and a control unit which controls ejecting of the ink from the first and second nozzles, in which, in a case of printing a darkest point, the control unit causes the second ink to be ejected after causing the first ink to be ejected, and causes the second ink to be ejected from the second nozzle so that a use rate of the second ink becomes 1% or more and 15% or less, when causing the second ink to be ejected.