Inkjet Printer White Ink Dot Size Control for Coverage
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Solution Overview
Problem
Inkjet printers with fewer heads for overcoat layer printing often fail to provide sufficient coverage of the lower layer, especially when printing on transparent media, resulting in inadequate visual effects due to insufficient light shielding and incomplete layer coverage.
Innovation Solution
An inkjet printer configuration with a first ink head for process color inks and a second ink head for white special color ink, where the dot size of the special color ink is larger than that of the process color ink, ensuring complete coverage by controlling the curing time and intensity of ultraviolet radiation for each ink type, without increasing the number of nozzles or ejection times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of heads for overcoat layer printing is smaller than the number of color ink heads, then the device complexity is reduced, but the coverage effect of the overcoat layer becomes insufficient
Solution Approach 1:
The patent applies local quality by making the dot size of the white ink (overcoat layer) larger than that of the color inks. Specifically, the white ink nozzles are configured to eject ink droplets with a larger diameter, allowing a single head to achieve better coverage through optimized local ink distribution rather than increasing the number of heads system-wide.
2Reliability
If the dot size of the special color ink is larger than that of the process color ink, then the coverage of the lower layer is improved, but the manufacturing precision may be affected
Solution Approach 1:
The patent changes the parameter of dot size differently for different ink types. The white ink is configured to produce larger dots (e.g., 0.06-0.08mm diameter) compared to color inks (e.g., 0.04-0.06mm diameter), allowing the system to optimize coverage for the overcoat layer while maintaining appropriate precision for the image layer through parameter differentiation.
3Reliability
If the curing time for white ink is extended to ensure complete coverage, then the coverage quality is improved, but the printing productivity is reduced
Solution Approach 1:
The patent applies preliminary action by having the color inks cured first before the white ink is ejected and cured. This sequential approach allows the white ink to be applied to already-cured color layers, preventing ink mixing and allowing optimized curing conditions for each layer without compromising overall printing speed.
Solution Approach 2:
The patent uses periodic action through separate curing cycles for different ink layers. The color inks are cured in one cycle, then the white ink is applied and cured in a subsequent cycle, allowing each curing process to be optimized independently while maintaining overall printing efficiency through rhythmic, alternating operations.
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 configuration ensures reliable coverage of the lower image layer by the special color ink, achieving the desired visual effect without compromising printing efficiency by maintaining the same nozzle array and ejection frequency.
Implementation Method 1
a light emitter that emits light to cure the color ink ejected onto the recording medium and the white ink ejected onto the color ink
Data Source
AI summary
A printer includes a first ink head that ejects a first ink, a second ink head that ejects a second ink, a first dot controller that controls a dot size after curing of the ejected first ink, and a second dot controller that controls a dot size after curing of the ejected second ink. The second ink is ejected over the first ink on a recording medium, and the second ink is caused to have a dot size that is larger than a dot size of the first ink.