Inkjet Dot Arrangement for Banding Reduction
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Solution Overview
Problem
Conventional inkjet recording apparatuses using linear base tones in halftone processes face issues with uneven printing results and banding due to varying impact points, which are not adequately addressed by existing techniques that only consider dot dispersity in the base tone direction, leading to increased dot dispersity and vertical lines.
Innovation Solution
The method involves forming dots such that those consecutively aligned in the base tone direction are printed in non-consecutive order, and those aligned in the sub-scanning direction are also printed in non-consecutive order, to disperse impact point deviations in both directions, thereby reducing banding and unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dots aligned in base tone direction are printed in consecutive order, then printing speed is improved, but dot impact position deviation increases causing banding and unevenness
Solution Approach 1:
The patent inverts the conventional printing approach by printing dots in reverse order of their arrangement. Specifically, dots that are spatially aligned in the base tone direction are printed in non-consecutive order, and dots aligned in the sub-scanning direction are printed in non-consecutive order. This inversion prevents cumulative positioning errors while maintaining efficient printing throughput.
Solution Approach 2:
The patent introduces dynamic printing sequences that adapt to dot position requirements. By varying the printing order dynamically based on spatial arrangement rather than following a fixed consecutive pattern, the system optimizes both speed and precision for different regions of the image.
2Device complexity
If conventional halftone processing with linear base tone is used, then image formation is simplified, but vertical lines and banding occur due to dot dispersity in sub-scanning direction
Solution Approach 1:
The patent addresses the one-dimensional limitation of conventional base tone processing by introducing considerations in both base tone direction and sub-scanning direction. This two-dimensional approach to dot arrangement and printing sequencing eliminates vertical line artifacts while preserving the simplicity of linear base tone halftone processing.
3Device complexity
If impact points are not dispersed in sub-scanning direction, then printing process is simplified, but dot dispersity increases causing vertical lines
Solution Approach 1:
The patent segments the printing process into distinct directional components (base tone direction and sub-scanning direction), applying non-consecutive printing orders to each segment. This segmentation allows independent optimization of each direction to prevent specific types of artifacts without overly complicating the overall process.
Data Source
AI summary
An imaging method is disclosed that is implemented in an image forming apparatus for forming a tone pattern on a recording medium by forming an arrangement of dots on the recording medium. The arrangement of dots is formed on the recording medium by jetting a recording liquid from a recording head while moving the recording head in a main scanning direction a plurality of times and intermittently conveying the recording medium in a sub-scanning direction that perpendicularly intersects the main scanning direction. The imaging method involves forming the arrangement of dots such that dots belonging to a first group that are consecutively aligned in a base tone direction and dots belonging to a second group that are consecutively aligned in the sub scanning direction are respectively formed in non-consecutive order on the recording medium.