Print Data Generation Unit for Sharp Image Quality
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Solution Overview
Problem
Ink jet printers face image degradation due to 'blur of colors' caused by interference between different ink colors, which is particularly noticeable in gray scale conversion methods that fail to achieve sharpness in picture quality.
Innovation Solution
A print control apparatus that generates print data using a combination of first gray scale conversion with a dither mask for the ink of the highest brightness color and second gray scale conversion with a line screen for other colors, effectively reducing the visibility of blur caused by ink interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gray scale conversion using a dither mask is employed to generate print data, then picture quality and gradation level are improved, but regular blur patterns appear due to ink interference
Solution Approach 1:
The patent divides the gray scale conversion process into two separate stages: first converting the brightness component using a dither mask to preserve gradation levels, then converting the color components using a line screen to eliminate regular blur patterns. This segmentation allows each component to be optimized independently for its specific requirements.
Solution Approach 2:
The patent applies different gray scale conversion methods to different color components: the brightness component (L in LAB color space) receives dither mask processing for high gradation quality, while the color components (a and b) receive line screen processing to prevent regular blur. This local differentiation optimizes each component's characteristics.
2Object-affected harmful factors
If gray scale conversion using a line screen is employed to achieve sharp picture quality, then regular blur is eliminated, but picture quality and gradation level deteriorate
Solution Approach 1:
The patent separates the processing of brightness and color information, applying line screen only to color components where regular blur occurs, while preserving dither mask processing for brightness where gradation quality is critical. This segmentation enables selective optimization.
Solution Approach 2:
Different gray scale conversion techniques are applied locally to different data components: line screen for color components (a, b) to eliminate regular blur, and dither mask for brightness component (L) to maintain gradation levels. This localized approach resolves the contradiction by matching the method to the specific requirements of each component.
3Adaptability or versatility
If ink of different colors is dispensed onto the printing medium, then color printing is achieved, but blur of colors occurs due to ink interference
Solution Approach 1:
The patent converts the harmful effect of ink interference into a beneficial outcome by using the line screen's regular pattern to counteract and eliminate the regular blur patterns that would otherwise be visible. The harm of ink interference is transformed into an opportunity to apply a compensating pattern.
Solution Approach 2:
The patent changes the parameter of gray scale conversion method based on color component characteristics. By switching from dither mask to line screen for color components, the patent modifies the processing parameters to match the specific problem of ink interference in color printing, thereby reducing blur while maintaining color printing capability.
Data Source
AI summary
Provided is a print control apparatus that dispenses ink of a plurality of colors through corresponding nozzles according to print data, to print an image on a printing medium. The print control apparatus includes a print data generation unit that generates, according to the image, the print data defining on/off setting of dots in each of pixels with respect to the ink of each of the plurality of colors. The print data generation unit generates the print data for the ink of a specific color having highest brightness among the plurality of colors through first gray scale conversion using a dither mask, and generates the print data for the ink of the plurality of colors except for the color subjected to the first gray scale conversion, through second gray scale conversion using a line screen.