UV Inkjet Head Gloss Control via Variable Printing Rate
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Solution Overview
Problem
The existing liquid discharging apparatuses using ultraviolet cure ink for printing result in uneven glossiness due to high surface roughness in areas with independent dots and linked dot groups, leading to variations in glossiness when these areas are mixed.
Innovation Solution
A liquid discharging apparatus and method that control the discharging head to vary the printing rate periodically or aperiodically at less than 100% in solid image areas based on raster data, reducing the formation of linked dots and thus minimizing gloss variations by adjusting the ink droplet size and printing rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the printing rate is maintained at 100% in solid image areas, then the printing efficiency is maximized, but the glossiness becomes uneven due to the formation of linked dots and dot groups with high surface roughness
Solution Approach 1:
The patent applies periodic action by intentionally varying the printing rate periodically within solid image areas. The controller causes printing rates lower than 100% to appear periodically along the printing direction, creating a cyclic pattern of dot group formations that suppresses excessive linking and reduces surface roughness variations, thereby achieving uniform glossiness while maintaining high overall printing efficiency
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the printing rate parameter within solid image areas. The controller varies the printing rate between 100% and lower values along the printing direction, changing the physical state of dot formation and linking behavior. This parameter modulation allows the system to achieve both high productivity and uniform glossiness by optimizing the printing rate according to the desired output quality
2Manufacturing precision
If the printing rate is reduced to suppress linked dots, then the glossiness uniformity is improved, but the printing efficiency decreases
Solution Approach 1:
The patent applies local quality by differentiating the printing rate treatment between different image areas. In solid image areas, the printing rate is varied periodically to suppress linked dot formation and improve glossiness uniformity, while in non-solid image areas, the printing rate can be maintained at 100% to preserve printing efficiency. This localized approach ensures quality improvement only where necessary
Solution Approach 2:
The patent implements partial action by applying printing rate reduction only to specific regions (solid image areas) rather than the entire image. The controller selectively varies the printing rate in solid image areas while maintaining 100% printing rate in other areas, achieving glossiness uniformity improvement without excessive impact on overall printing efficiency
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 glossiness variations across the recording medium by reducing the number of linked dots and dot groups, resulting in a more uniform finish, especially on non-osmotic media like resin and metal.
Implementation Method 1
By irradiating the ink liquid droplets landed on the recording medium with ultraviolet rays, the ink is cured and then fixed on the recording medium
Data Source
AI summary
A liquid discharging apparatus includes: a discharging head configured to discharge an ultraviolet cure ink onto a recording medium; and a controller configured to control the discharging head to: discharge the ink onto the recording medium on the basis of a raster data for an image to be formed on the recording medium, the image including a solid image area formed with the raster data at 100% of a printing rate; and execute a gloss reduction printing in which the solid image area is printed on the recording medium by varying the printing rate such that printing rates lower than 100% appear along a printing direction periodically or aperiodically in the course of 100% printing rate.