Printhead Monitoring With Real-Time Banding Correction
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Solution Overview
Problem
Current methods for monitoring print head functionality are time-consuming and disruptive, failing to address individual nozzle issues effectively, leading to banding and inconsistent color reproduction across different substrates.
Innovation Solution
A method involving color management systems and imaging measurement to continuously monitor and correct print head performance by converting image files between RGB, L*a*b*, and CMYK color spaces, using ICC profiles and spectral imaging to identify and adjust print head malfunctions without interrupting the printing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If banding correction is performed using test forms printed and analyzed offline or with interrupted printing, then print quality can be improved, but productivity decreases and the printing process is interrupted
Solution Approach 1:
The patent implements continuous monitoring during the printing process by integrating the measurement system into the printing workflow. The system measures print quality parameters continuously without stopping the printing operation, allowing real-time detection of banding and nozzle defects while maintaining productive printing activity throughout the process.
Solution Approach 2:
The system incorporates real-time feedback mechanisms where measurement data from the printing process is immediately analyzed and used to generate control corrections. This closed-loop feedback system allows the printing process to self-adjust for banding and nozzle issues without requiring manual intervention or process interruption, thereby maintaining both quality and productivity.
2Manufacturing precision
If control voltages on print heads are changed to correct banding, then print quality improves, but individual nozzle issues cannot be addressed and color consistency deteriorates
Solution Approach 1:
The patent divides the print head into individually controllable nozzle segments or groups. The control system can independently adjust voltages or control parameters for specific nozzle regions based on measured defects, enabling precise localization and correction of individual nozzle issues while maintaining overall color consistency across the print width.
Solution Approach 2:
The system implements localized control and correction strategies where different regions of the print head receive customized control parameters based on their specific performance characteristics. This allows individual noisy or defective nozzles to be addressed with targeted adjustments while other regions operate at optimal settings, thereby improving both color consistency and operational precision.
3Productivity
If printing is performed at high speed, then productivity increases, but detection and measurement of print defects becomes more difficult
Solution Approach 1:
The system performs measurement and analysis actions during the printing process rather than after completion. By continuously monitoring print quality parameters in real-time at high printing speeds, the system can detect defects immediately as they occur, allowing for timely corrections without requiring slower printing speeds for measurement purposes.
Data Source
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AI summary
The invention relates to a method for monitoring the functionality of at least one print head, in which correction values for a print image file generated from an input image file with original resolution are calculated by measuring correction values as the difference between a measured scan image and a comparison file generated from the input image file. The correction values are transferred from the scan resolution to the original resolution in an intermediate step.