Inkjet Nozzle Malfunction Detection via Substrate Image Analysis
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Solution Overview
Problem
Inkjet printers face significant productivity losses due to nozzle malfunctions, which are difficult to detect and require frequent manual monitoring or costly sensor systems, leading to production downtime and quality issues.
Innovation Solution
A device comprising a lighting source, camera system, control unit, and evaluation unit that sequentially illuminates substrates with printing colors and uses image processing to detect nozzle malfunctions, allowing for automatic evaluation of faulty patterns and decision-making on production continuation or cleaning cycles based on visibility thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual observation by operator is performed regularly, then nozzle malfunctions are detected, but production downtime increases and labor costs increase
Solution Approach 1:
The system enables self-service monitoring by automatically detecting nozzle malfunctions through image processing without requiring operator intervention. The evaluation unit continuously analyzes printed patterns and autonomously identifies defective nozzles, replacing manual visual inspection with an automated self-monitoring mechanism.
Solution Approach 2:
The patent replaces the mechanical/Manual inspection system with an automated optical detection system. A camera captures images of printed substrates, and image processing algorithms automatically analyze the patterns to detect nozzle failures, substituting human visual observation with automated optical-mechanical systems.
2Reliability
If frequent routine cleaning cycles are performed, then nozzle blockages are prevented, but production losses increase
Solution Approach 1:
The system performs preliminary detection of nozzle malfunctions before they cause significant quality defects. By continuously monitoring printed patterns and identifying early signs of nozzle failure, the system enables timely intervention only when necessary, preventing the need for frequent preventive cleaning cycles.
Solution Approach 2:
The patent changes the monitoring approach from time-based periodic cleaning to condition-based detection. Instead of cleaning at fixed intervals, the system continuously monitors print quality parameters and triggers cleaning only when actual nozzle malfunctions are detected, adapting the maintenance schedule to actual device condition.
3Measurement precision
If integrated sensors are installed in printheads, then individual nozzle monitoring is achieved, but design complexity and costs increase
Solution Approach 1:
The patent extracts the monitoring function from the printhead itself and places it externally. Instead of embedding sensors within the printhead structure, the system uses a separate camera and image processing unit to detect nozzle malfunctions by analyzing printed patterns on the substrate, separating the monitoring function from the printing function.
Solution Approach 2:
The substrate with printed pattern serves as an intermediary medium for detection. Rather than directly sensing nozzle status, the system uses the printed output on the substrate as an indirect indicator of nozzle health, allowing malfunction detection through pattern analysis without requiring direct access to nozzle internal state.
4Measurement precision
If test patterns are printed and analyzed, then nozzle defects are detected, but production interruption occurs
Solution Approach 1:
The system maintains continuous monitoring of nozzle functionality during normal production printing. Instead of interrupting production to print separate test patterns, the system continuously analyzes patterns printed during regular operation, ensuring uninterrupted production flow while maintaining constant quality monitoring.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables early detection of nozzle errors, reduces unnecessary production interruptions, and increases productivity by only initiating maintenance when errors exceed visibility thresholds, thus minimizing production losses.
Implementation Method 1
the decorated substrate being sequentially illuminated with light in the colors of the printing inks used by the at least one illumination source
Implementation Method 2
images of the print pattern of the decorated substrate captured by the camera system
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The nozzle assembly has a nozzle head for dropwise application of pressurized fluid to a substrate. A monitoring module is located for detection of malfunctions of the nozzles of the nozzle head. The image sensor (5) and the illumination unit (9) are located in a common housing (12). The nozzle fasteners (13) are provided to connect monitoring module and the nozzle head. A connecting device is connected with monitoring module and the print head through electrical signal lines (14).