Print Head Conveying Amount Adjustment for Streak Prevention
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Solution Overview
Problem
Ink-jet printers face challenges in achieving high-speed printing due to issues like 'white streak' and 'black streak' caused by dot displacement, which affect image quality and density, especially when multiple print heads with different characteristics are used on a single guide, making it difficult to set a proper conveying amount for each print head.
Innovation Solution
A printing apparatus with a conveying unit that intermittently conveys a recording medium, a storage unit to store conveying amounts, and a control unit to determine and adjust the conveying amounts based on a test pattern to prevent displacement between regions printed by multiple print heads, ensuring optimal image quality by selecting the appropriate conveying amount for each print head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple print heads are mounted on one guide to increase printing speed, then productivity is improved, but manufacturing precision deteriorates due to difficulty in fitting conveying amount to each print head's characteristics
Solution Approach 1:
The patent divides the printing system into multiple independent print heads (first print head and second print head) mounted on a common guide. Each print head has its own conveying amount adjustment capability, allowing independent optimization of dot position accuracy for each head while maintaining high-speed parallel printing. This segmentation enables each print head to be tuned individually without affecting others, resolving the contradiction between multi-head productivity and precision.
2Manufacturing precision
If conveying amount is adjusted to fit one print head's characteristics, then manufacturing precision is improved for that print head, but object-generated harmful factors worsen due to streaks in regions printed by other print heads
Solution Approach 1:
The patent implements local quality adjustment by providing individual conveying amount control for each print head. The first print head has a first conveying amount and the second print head has a second conveying amount, which can be independently optimized based on their respective characteristics. This localized adjustment eliminates streaks in each print head's specific printing region while maintaining overall system precision, preventing the harmful effects that would result from uniform adjustment across all heads.
3Productivity
If printing width is increased to reduce printing time, then productivity is improved, but object-generated harmful factors worsen due to increased dot displacement and streaks
Solution Approach 1:
The patent segments the printing system into multiple print heads that operate in parallel, effectively increasing the printing width without requiring a single oversized print head. Each segmented print head maintains its own optimized conveying amount, preventing dot displacement and streak formation even as the overall printing capacity increases. This segmentation allows high-speed wide-format printing while maintaining image quality.
Solution Approach 2:
By providing individual conveying amount adjustment for each print head, the patent ensures that local printing quality is maintained across the entire printing width. Each print head's conveying amount is optimized for its specific characteristics, preventing the formation of white streaks (from excessive conveying) and black streaks (from insufficient conveying) that would otherwise occur in wide-format printing.
Data Source
AI summary
A printing apparatus including a plurality of printing units along one guide can read test patterns printed with a plurality of types of conveying amount of a recording medium and determine a conveying amount based on the reading result.