Image Processing Method for Staggered Nozzle Black Ruled Line Thickness Control
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Solution Overview
Problem
In image processing for printers with staggered nozzle arrangements, there is a risk of black ruled lines appearing thicker than intended due to resolution reduction and ink combination issues between black and color ink nozzle rows, leading to visible thickness and potential image quality degradation.
Innovation Solution
An image processing method that reduces the resolution of image data in the sub-scanning direction by processing each N-unit region, generating recording data that includes dot generation for black ink pixels based on gradation values, and performing color conversion and halftone processing to ensure accurate ink discharge from staggered nozzle rows, thereby controlling the appearance of black ruled lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resolution reduction processing is performed on image data for a printer with staggered nozzle rows, then the recording speed and processing efficiency are improved, but black ruled lines may appear thicker than intended due to ink discharge from both black and color nozzle rows
Solution Approach 1:
The patent applies local quality by differentiating processing between black pixels and non-black pixels. For black pixels, the system selectively discharges black ink from the black nozzle row while suppressing color ink discharge from the color nozzle row. For non-black pixels, normal ink discharge proceeds. This localized differentiation ensures that black ruled lines maintain their intended thickness while other image elements are processed normally, resolving the contradiction between recording speed and line thickness accuracy.
Solution Approach 2:
The patent segments the ink discharge process into separate control paths for black ink and color ink based on pixel content. The image data is processed to identify black pixels, and the ink discharge is segmented such that black pixels trigger only black nozzle activation while non-black pixels allow both black and color nozzles to operate. This segmentation prevents unwanted color ink discharge that would otherwise thicken black ruled lines during resolution reduction processing.
2Area of stationary object
If both black ink nozzle row and color ink nozzle row are used for recording, then the coverage and color capability are improved, but black ruled lines may be recorded at a coarser interval causing visible thickness
Solution Approach 1:
The patent applies local quality by making the ink discharge behavior dependent on the specific pixel content. When a pixel is identified as black, the system locally adjusts the discharge behavior to use only the black nozzle row, preventing the color nozzle row from adding extra ink that would thicken the line. For non-black pixels, both nozzle rows operate normally to maintain coverage and color capability. This selective local adjustment resolves the contradiction between coverage and line width precision.
3Device complexity
If resolution is reduced from X×N dpi to X dpi in the sub scanning direction, then the data processing load is reduced, but the interval between black ink dots increases causing thicker appearance
Solution Approach 1:
The patent applies local quality by implementing different processing rules for black pixels versus non-black pixels during resolution reduction. For black pixels, the system maintains precise dot spacing by selectively activating only the black nozzle row and suppressing color nozzle discharge. For non-black pixels, standard resolution reduction processing applies. This localized differentiation allows the system to reduce data processing complexity while maintaining accurate dot spacing for black ruled lines.
Data Source
AI summary
An image processing method is an image processing method of a recording device. The image processing method includes inputting the image data having a resolution in a sub scanning direction of X×N dpi, performing data processing on the image data for each N-unit region, performing resolution reduction processing of reducing, to 1/N, a resolution in the sub scanning direction, and generating a recording data based on the reduced image data. In the data processing step, when the N-unit region is formed of a pixel having a black gradation value and a pixel having a gradation value that is equal to or greater than a predetermined value when expressed by RGB, and the pixel having the black gradation value is consecutive from another N-unit region adjacent to the N-unit region, a black dot is generated in a pixel after the resolution reduction processing.