Inkjet Nozzle Detection via Shrunken Image Printing
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Solution Overview
Problem
Existing methods for detecting and compensating for defective printing nozzles in inkjet printing machines are inefficient, leading to increased waste and complex quality control processes, as they often rely on test charts that differ from actual prints, causing false positives and necessitating post-print detection, which results in delayed compensation and increased waste.
Innovation Solution
A method involving shrinking the digitally available image to a print control strip height, allowing for detection and compensation of defective nozzles by printing a shrunk image with unchanged width onto the substrate ahead of the actual image, using image sensors and computer analysis to identify and compensate for defects without creating waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If test charts are printed and analyzed to detect defective nozzles, then nozzle detection is enabled, but false positives occur and waste increases
Solution Approach 1:
The patent creates a digital copy (shrunken version) of the actual image to be printed and uses this copy for nozzle detection. By shrinking the image dimensions while maintaining the same pattern structure, the system can analyze nozzle performance on a reduced-scale representation that accurately reflects the printing behavior on the full-size image, eliminating the need for separate test charts and reducing substrate waste.
Solution Approach 2:
The patent changes the scale parameter of the image by shrinking it to a smaller dimension while maintaining the same printing patterns. This parameter transformation allows the detection system to analyze nozzle performance on a compact representation that preserves all necessary information about nozzle functionality, thereby enabling accurate detection without requiring full-size test prints that would consume additional substrate.
2Ease of operation
If test charts differ from actual prints, then detection process is simplified, but false positives increase
Solution Approach 1:
Instead of using completely different test charts, the system creates a shrunken copy of the actual image to be printed. This copy maintains the same patterns, color distributions, and printing characteristics as the original image, ensuring that nozzle behavior detected on the shrunken version accurately reflects behavior on the full-size print, thereby eliminating false positives while keeping the process simple.
Solution Approach 2:
The system performs nozzle detection by printing the shrunken image before the actual full-size image. This preliminary action allows defective nozzles to be identified and compensated for in advance, ensuring that the main printing process proceeds with accurate nozzle functionality knowledge, thus preventing defects in the final print without requiring complex post-print analysis.
3Measurement precision
If defective nozzles are detected after printing, then comprehensive detection is achieved, but compensation is delayed and waste increases
Solution Approach 1:
The system performs nozzle detection by printing a shrunken version of the image before the actual printing process. This preliminary detection allows defective nozzles to be identified and compensated for in advance, so that when the full-size image is printed, the compensation parameters are already available, eliminating delays and preventing waste from defective printing.
Solution Approach 2:
The system implements a feedback loop where the shrunken image is printed, analyzed for defective nozzles, and the detection results are used to adjust compensation parameters before the main printing process. This feedback mechanism ensures that nozzle defects are detected comprehensively and that compensation is applied immediately, preventing defective nozzles from affecting the final print quality.
Data Source
AI summary
A method for detecting and compensating for defective printing nozzles in an inkjet printing machine by using a computer, includes shrinking the height of a digitally available image to the image height of a print control strip by using the computer while the image width remains uninfluenced, printing the shrunk digital image onto a printing substrate, recording the printed shrunk digital image by using at least one image sensor, comparing the recorded image with the shrunk digital image by using the computer, detecting defective printing nozzles for the digital image by using the computer based on the comparison and compensating for the detected defective printing nozzles. The digital image is printed onto the following printing substrate by using defective printing nozzle compensation.