Offset Printing Halftone Imaging for Continuous Defect Prevention
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Solution Overview
Problem
Existing offset printing machines suffer from deteriorating print quality due to changes in halftone dot shape, which is difficult to detect through visual inspection, leading to defective printed matter and reduced production efficiency, especially when using roll paper.
Innovation Solution
A print quality control system that includes an imaging device to capture halftone dot patterns on paper and a determining device to compare them with ideal shapes, using machine learning to predict and prevent print quality deterioration by adjusting printing conditions without stopping the machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection by operator using magnifying monitoring device is used to confirm halftone dot shape, then print quality can be confirmed, but work time is prolonged and production efficiency deteriorates
Solution Approach 1:
The patent replaces the manual visual inspection system with an automated image processing system. An imaging device captures halftone dot patterns, and a determining device with calculation part automatically analyzes the captured images to confirm halftone dot shapes, eliminating the need for operators to use magnifying monitoring devices and thereby maintaining production speed while ensuring accurate quality control
Solution Approach 2:
The system creates digital copies of halftone dot patterns through imaging and stores them as reference data. The determining device compares captured images against stored reference images to automatically confirm quality, replacing the need for direct visual inspection while preserving the ability to accurately assess halftone dot shapes
2Reliability
If operator visually inspects printed matter to detect defective printed matter, then quality control is achieved, but detection time is delayed and defective printed matter is produced
Solution Approach 1:
The imaging device is positioned to continuously capture halftone dot patterns during the printing process without interruption. The determining device processes images in real-time as they are captured, enabling continuous quality monitoring that detects defects immediately rather than through delayed visual inspection, thus preventing defective printed matter while maintaining production flow
Solution Approach 2:
The system establishes a feedback loop where captured images are immediately analyzed by the determining device, and results are used to detect quality deterioration in real-time. This continuous feedback mechanism allows for immediate detection of defective printed matter and enables timely adjustments to printing conditions
3Measurement precision
If offset printing machine stops to visually confirm printed matter using magnifying monitoring device, then halftone dot shape can be confirmed, but production speed is reduced
Solution Approach 1:
The patent replaces the stop-and-inspect mechanical process with a continuous automated imaging and analysis system. The imaging device captures halftone dot patterns during machine operation, and the determining device with calculation part processes images automatically, eliminating the need to stop the printing machine while ensuring accurate halftone dot shape confirmation is maintained
Solution Approach 2:
The system performs preliminary imaging and analysis of halftone dot patterns during normal printing operations. By continuously capturing and analyzing images before quality deterioration becomes severe, the system maintains production speed while ensuring quality control through advance detection of shape variations
Data Source
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AI summary
Provided is a print quality control device of an offset printing machine in which an operator is notified of a control for suppressing an occurrence of a defective printed matter at an early stage or the control can be automatically executed, when there exists a sign that the defective printed matter will be caused due to deterioration in the print quality. A print quality control system for an offset printing machine is configured to print a pattern and a shape confirmation halftone dot pattern on a paper and comprises an imaging device for capturing the shape confirmation halftone dot pattern printed on the paper and a determining device which are provided on a paper conveying path, the determining device is configured to confirm a change in a halftone dot shape based on an image of the shape confirmation halftone dot pattern and notify the operator of or execute automatically the control for suppressing the occurrence of the defective printed matter, when the print quality of printed matter would be deteriorated and the defective printed matter would be caused if printing continues as it is.