Print Data Generation for White Ink Optimization on Dark Media
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Solution Overview
Problem
Conventional methods for printing white ink on dark-colored recording media, such as black, require excessive white ink and fail to maintain image quality due to mismatched inverted brightness and white ink usage.
Innovation Solution
A print data generating apparatus and method that converts input image data into CMYK format, calculating white scale values by inverting black scale values, allowing for optimal white ink usage and image quality on various media colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a solid white base layer is formed on dark-colored recording media, then image quality is improved, but white ink usage increases significantly
Solution Approach 1:
Instead of inverting the entire image to determine white ink amounts, the patent inverts only the black channel data to calculate white scale values. This selective inversion approach allows the system to leverage the existing dark background of the recording medium, eliminating the need for a solid white base layer while maintaining image quality and reducing white ink consumption.
Solution Approach 2:
The patent changes the parameter used for white ink calculation from inverted brightness (0-255 scale) to inverted black channel scale values. This parameter transformation enables precise control of white ink ejection amounts, allowing the system to achieve optimal image quality with minimal white ink by directly controlling the white scale values based on the recording medium's characteristics.
2Ease of manufacture
If inverted brightness is used to determine white ink amount, then processing is simplified, but white ink usage does not correspond to actual requirements
Solution Approach 1:
The patent applies local quality by processing only the black channel data separately from the color channels. Instead of inverting the entire image data, it extracts and inverts only the black component (K channel in CMYK), allowing precise control of white ink amounts specific to each pixel's black content while maintaining simplicity in the processing workflow.
Solution Approach 2:
The patent transforms the parameter from inverted brightness to inverted black channel scale values. This parameter change maintains processing simplicity while significantly improving the accuracy of white ink amount determination, as the black channel directly reflects the recording medium's characteristics and the actual ink requirements.
3Adaptability or versatility
If discharge printing is performed on dark-colored media, then colored image formation is enabled, but image quality deteriorates due to insufficient white ink
Solution Approach 1:
The patent applies inversion by calculating white scale values as the complement of black scale values (255 - black_scale_value). This inversion approach allows the system to adapt to dark-colored recording media by automatically adjusting white ink amounts based on the medium's characteristics, thereby maintaining image quality while enabling printing on previously unsuitable surfaces.
Solution Approach 2:
The patent changes the control parameter to white scale values derived from inverted black channel data. This parameter transformation enables precise control of white ink ejection, allowing the system to adapt to various dark-colored media types while maintaining consistent image quality through accurate white ink dosage control.
Data Source
AI summary
A print data generating apparatus to generate print data, which is to be used in a printing apparatus to form an image in a plurality of colorants, based on originally inputted image data representing the image, is provided. The print data generating apparatus includes a black enabled image data converter unit to convert the inputted image data into black enabled image data, which indicates scale values of a plurality of colors including a black color to be used in the image, a white scale value calculator unit to obtain scale values of a white color to be used in the image to be formed. The white scale value calculator unit calculates the scale values of the white color by inverting the scale values of the black color obtained in the conversion by the black enabled image data converter unit.