Inkjet Head Ejection Adjustment via Judging Patterns
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Solution Overview
Problem
Inkjet printers face issues with uneven ink ejection due to variations in nozzle characteristics and gaps between the inkjet head and print sheet, leading to image quality deterioration, as the existing techniques struggle to accurately adjust ejection conditions across different areas of the print sheet.
Innovation Solution
The method involves forming ejection adjustment patterns with thickness measurement patterns and judging patterns on the print medium, using line-like patterns to detect positional relationships and identify ideal ejection conditions, allowing for precise adjustment of nozzle ejection conditions to compensate for gap variations and ensure consistent image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thickness measurement patterns are formed to adjust ink ejection characteristics, then ink ejection uniformity is improved, but measurement accuracy deteriorates due to gap variations between inkjet head and print sheet
Solution Approach 1:
The patent introduces judging patterns as intermediary elements that indirectly measure gap conditions. Instead of directly measuring thickness (which is affected by gap variations), the judging patterns serve as mediators to detect positional relationships between inkjet head and print sheet, allowing compensation for gap variations in thickness measurements
Solution Approach 2:
The patent replaces direct mechanical thickness measurement with an optical/detector-based system that measures positional relationships through judging patterns. The detector captures images of judging patterns to determine positional deviations, substituting mechanical measurement with a different measurement approach that is less sensitive to gap variations
2Productivity
If bi-directional printing is used to improve productivity, then printing speed is improved, but image quality deteriorates due to spotter position displacement from gap unevenness
Solution Approach 1:
The patent implements feedback by measuring actual spotter positions through judging patterns and using this information to adjust ink ejection conditions. The system continuously monitors positional deviations caused by gap variations and compensates by adjusting ejection parameters, allowing bi-directional printing to maintain image quality
Solution Approach 2:
The patent changes ejection parameters (such as ejection timing, ejection energy, or droplet size) based on measured gap conditions and positional deviations. By dynamically adjusting these parameters in response to detected variations, the system maintains consistent image quality while utilizing bi-directional printing for high productivity
3Manufacturing precision
If multiple thickness measurement patterns are formed to compensate for nozzle unevenness, then ink ejection uniformity is improved, but measurement reliability deteriorates when gap conditions vary across different areas
Solution Approach 1:
The patent applies local quality by forming multiple judging patterns at different positions across the print sheet to locally characterize gap conditions in each area. This allows the system to understand and compensate for local variations in gap, making thickness measurements more reliable even when overall gap conditions are non-uniform
Solution Approach 2:
The patent segments the measurement process by dividing the print sheet into multiple pattern forming areas, each with its own thickness measurement pattern and judging pattern. This segmentation allows independent analysis of each area's gap conditions and ejection characteristics, improving overall measurement reliability through localized optimization
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 approach effectively identifies and adjusts for variations in gap conditions across the print sheet, resulting in improved image quality by ensuring consistent ink drop placement and thickness, even in bi-directional printing scenarios.
Implementation Method 1
forming a plurality of thickness measurement patterns respectively on a plurality of pattern forming areas defined on the print medium by causing the plurality of nozzles of the inkjet head to eject ink drops
Data Source
AI summary
An ejection adjustment pattern forming method of forming an ejection adjustment pattern on a print medium with an inkjet head, which has a plurality of nozzles, with moving the inkjet head in a predetermined scanning direction. The method forms a plurality of thickness measurement patterns respectively on a plurality of pattern forming areas defined on the print medium by causing the plurality of nozzles of the inkjet head to eject ink drops, and forms a plurality of judging patterns respectively on the plurality of pattern forming areas. The ejection conditions of the plurality of nozzles, when the plurality of thickness measurement patterns are formed, are the same among the plurality of pattern forming areas. Further, the ejection conditions of the plurality of nozzles when the first judging pattern is formed and when the second judging pattern is formed are the same among the plurality of pattern forming areas.