Inkjet Printer Nozzle Ejection Control for Striped Variation
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Solution Overview
Problem
Inkjet printers face challenges in maintaining consistent ejection characteristics of nozzles, leading to striped variations and reduced image quality, especially in high-speed single-scan printing systems, where abnormal nozzles affect the printed result.
Innovation Solution
The implementation of an inkjet printer system that adjusts ejection control signals for each nozzle to bring the average ejection errors close to zero, utilizing gradation control functions to correct abnormal nozzles without requiring complex changes, allowing for high-quality printing in single-scan systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single-scan printing system is used for high-speed printing, then printing speed is improved, but nozzle ejection characteristic variation directly affects printed result causing striped variation
Solution Approach 1:
The patent applies local quality by differentiating ejection control between normal nozzles and abnormal nozzles. The ejection control unit identifies abnormal nozzles and applies corrected ejection control signals specifically to these nozzles, while normal nozzles use standard control signals. This localized correction approach maintains high-speed single-scan printing while compensating for ejection characteristic variations in specific nozzles, thereby preventing striped variation and maintaining image quality.
2Manufacturing precision
If nozzle ejection characteristics are controlled with extremely high accuracy, then ink droplet volume consistency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements feedback by measuring the ejection characteristics of each nozzle and using this information to generate corrected ejection control signals for abnormal nozzles. The ejection control unit receives feedback on nozzle performance and adjusts the ejection control signals accordingly, allowing the system to compensate for manufacturing variations without requiring extremely high manufacturing precision, thus reducing device complexity and manufacturing difficulty.
3Manufacturing precision
If multi-scan printing system is used to average nozzle variation, then image quality is improved, but printing speed decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing corrected ejection control signals for each abnormal nozzle based on its measured ejection characteristics. During single-scan printing, these pre-prepared correction signals are applied directly without requiring multiple scanning passes. This preliminary correction approach enables the system to achieve image quality comparable to multi-scan systems while maintaining high-speed single-scan operation.
Data Source
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AI summary
(Problem to be Solved) To appropriately restrain occurrence of striped variation and to appropriately enhance image quality of a printed result. (Solution) An inkjet printer in which multi-gradation printing is performed in an inkjet method includes an ejection control section for controlling ejection of ink droplets by supplying an ejection control signal to a nozzle for controlling ejection of the ink droplets from the nozzle of an inkjet head. The inkjet head forms lines of ink dots juxtaposed in a line direction so that the lines are juxtaposed in a direction perpendicular to the line direction. In a case that a nozzle which forms a line is the abnormal nozzle, an ejection control signal corresponding to an ink dot size which is different from a case of the normal nozzle is supplied as the ejection control signal corresponding to a part of the dots juxtaposed in the line, thereby an average value in the line of ejection errors is brought close to zero.