Dynamic Inkjet Nozzle Test Pattern Adaptation
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Solution Overview
Problem
Current methods for detecting defective print nozzles in inkjet printing machines are inefficient, leading to delayed detection and increased wastage due to static test patterns that cannot accurately assess nozzle serviceability, especially in volatile print head regions, resulting in poor printing quality.
Innovation Solution
A dynamic method where print nozzle test patterns are printed and evaluated in two phases: the first phase determines the current nozzle state, and the second phase modifies the test patterns to focus on critical regions, increasing the frequency of checks for faulty nozzles, using a computer to adapt and distribute test patterns based on nozzle conditions, ensuring more accurate and timely detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If static print nozzle test patterns are used for detection, then the detection method is simple, but the detection accuracy and timeliness deteriorate due to inability to adapt to volatile nozzle conditions
Solution Approach 1:
The patent implements dynamic test patterns that adapt to the actual printing conditions and nozzle states. The system continuously monitors printing quality and adjusts test pattern parameters (such as line density, spacing, and positioning) in real-time to match the volatile conditions of print head regions, enabling accurate detection of nozzle defects that static patterns cannot detect.
Solution Approach 2:
The system changes test pattern parameters dynamically based on detected nozzle conditions. When nozzle serviceability deteriorates or printing conditions change, the test pattern parameters are adjusted to optimize detection sensitivity, allowing the system to maintain high detection accuracy across varying operational states.
2Loss of time
If test patterns are printed frequently to improve detection timeliness, then detection accuracy improves, but printing productivity deteriorates due to increased test pattern printing time
Solution Approach 1:
The system implements periodic test pattern printing at optimized intervals rather than continuous printing. Test patterns are printed at strategically determined time points during the printing process, balancing the need for timely defect detection with the requirement to maintain overall printing productivity. The periodic intervals are adjusted based on nozzle stability and printing conditions.
Solution Approach 2:
The system applies partial testing by selecting specific critical regions of the print head for focused test pattern printing rather than testing all nozzles uniformly. This partial action approach concentrates detection resources on volatile regions that require monitoring, reducing overall test printing time while maintaining effective detection of critical nozzle defects.
3Device complexity
If uniform test patterns are applied to all print head regions, then the detection process is simple, but detection effectiveness deteriorates in volatile regions due to lack of targeted assessment
Solution Approach 1:
The patent applies different test pattern characteristics to different regions of the print head based on their volatility and criticality. Volatile regions receive test patterns with higher sensitivity parameters, while stable regions use standard patterns. This local quality approach ensures that each region is assessed with the appropriate detection sensitivity, improving overall detection reliability without excessive complexity.
Solution Approach 2:
The system segments the print head into different regions based on nozzle volatility and criticality, applying differentiated test patterns to each segment. This segmentation allows the system to focus detection resources on critical volatile regions while using simpler patterns in stable regions, optimizing both detection effectiveness and process complexity.
4Measurement precision
If continuous monitoring of all nozzles is performed, then detection completeness improves, but system complexity and processing time deteriorate
Solution Approach 1:
The system performs partial monitoring by focusing on critical volatile regions rather than continuously monitoring all nozzles equally. Test patterns are strategically positioned to assess the most critical regions with higher probability of nozzle failure, achieving effective detection completeness while reducing system complexity and processing requirements.
Solution Approach 2:
The system extracts and isolates the most critical volatile regions for focused monitoring, separating them from the rest of the print head. By taking out these critical regions for specialized attention with adapted test patterns, the system achieves high detection completeness for problematic areas without the complexity of uniform continuous monitoring of all nozzles.
Data Source
AI summary
A method detects defective print nozzles in an inkjet printing machine by a computer. In a first phase within the context of a print job, print nozzle test patterns are printed beside a subject on a printing substrate. These print nozzle test patterns are then digitized by an image sensor and sent to the computer, where they are analyzed by the computer to determine the current state of the print nozzles, including defective print nozzles. After the first phase, the print nozzle test patterns are modified by the computer on the basis of the current state of the print nozzles and, in a second phase, the modified print nozzle test patterns are printed, digitized and evaluated by the computer with regard to the determination of the current state of the print nozzles and defective print nozzles.