Ejection Timing Adjustment for Multi-Head Printers
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Solution Overview
Problem
Existing methods for adjusting ejection timing in printers with multiple heads are hindered by movement errors caused by decentering of drive pulleys, making it difficult to accurately align the landing positions of liquid droplets due to indeterminable varying error components.
Innovation Solution
A method involving the formation of adjustment patterns by shifting relative ejection timings of liquid droplets from multiple nozzle rows, with patterns separated by a predetermined distance, and adjusting the ejection timing based on the average of these patterns to account for movement errors, particularly using a rotating member's half rotation distance for pattern separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adjustment patterns are formed using a single ejection timing setting, then the adjustment process is simple, but the movement error caused by decentering cannot be properly compensated
Solution Approach 1:
The patent divides the adjustment process into multiple segments by forming multiple adjustment patterns at different ejection timing settings. Instead of using a single adjustment pattern, the system creates several patterns (first adjustment pattern, second adjustment pattern, etc.) with different timing offsets. This segmentation allows the system to capture movement error characteristics at different timing points, enabling more accurate compensation of the decentering error through comparative analysis of the patterns.
2Manufacturing precision
If multiple adjustment patterns are formed at different positions, then the movement error can be compensated, but the adjustment process becomes more complex
Solution Approach 1:
The patent employs periodic action by forming adjustment patterns at regular intervals in the movement direction. The first adjustment pattern is formed at a first position, the second adjustment pattern at a second position, with each subsequent pattern spaced at predetermined intervals. This periodic arrangement creates a systematic sampling of movement error characteristics throughout the scanning range, allowing the controller to identify error patterns and compensate accurately without requiring complex adaptive algorithms.
3Measurement precision
If the head position is fixed during adjustment, then the measurement is simple, but the movement error caused by decentering cannot be detected
Solution Approach 1:
The patent introduces dynamics into the adjustment process by moving the head to different positions during the formation of adjustment patterns. Instead of keeping the head stationary, the system forms the first adjustment pattern at a first position, then moves the head to a second position to form the second adjustment pattern, and continues this dynamic positioning. This dynamic approach allows the system to detect movement errors caused by decentering by comparing the relative positions of droplets across different patterns, while the overall system remains manageable through automated control.
Data Source
AI summary
The invention relates to a method for adjusting ejection timing including: forming adjustment patterns on a medium by shifting relative ejection timings of liquid droplets from a first nozzle row and a second nozzle row lined up in a direction intersecting a row direction in which nozzles of the first nozzle row and the second nozzle row are lined up, while shifting the first nozzle and the second nozzle in respect to the medium in the intersecting direction of the first nozzle row and the second nozzle row; and determining adjustment amounts of relative ejection timings of the first nozzle row and the second nozzle row based on the adjustment patterns, wherein the adjustment patterns are formed in the intersecting direction in a plural number separated from each other by a predetermined distance, and the ejection timing is adjusted based on an average of the adjustment amounts determined based on the adjustment patterns.