Line-Scan Camera Inspection for Intaglio Printing Vibration Isolation
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Solution Overview
Problem
In-line inspection of printed material on intaglio printing presses using line-scan cameras is hindered by vibrations and shocks generated during the printing process, leading to optical aberrations and errors, making matrix-type cameras the preferred choice despite their lower performance and potential for optical deformations.
Innovation Solution
An in-line inspection system employing one or more line-scan cameras positioned transversely to the sheet path, combined with an intermediate transfer unit and a suction unit, which guides and supports the sheets to minimize the impact of cyclical vibrations, ensuring accurate image acquisition by aligning the inspection location with the sheet periodicity and using illumination and blowing devices for optimal image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If line-scan cameras are used for in-line inspection on intaglio printing presses, then measurement precision and image quality are improved, but vibrations and shocks during printing cause optical aberrations and errors
Solution Approach 1:
An intermediate transfer unit is introduced between the printing press and the inspection system. This intermediary component receives printed sheets from the printing press and transports them to the inspection location, isolating the line-scan camera from the vibrations and shocks generated during the printing process, thereby enabling high-precision imaging without optical aberrations
Solution Approach 2:
The inspection system is separated from the printing process into distinct functional modules: the printing press, the intermediate transfer unit, and the inspection system with line-scan camera. This segmentation allows the inspection component to operate in a vibration-free environment while the printing process continues independently
2Reliability
If matrix-type cameras are used for in-line inspection, then resistance to vibrations is improved, but manufacturing precision and inspection accuracy deteriorate due to optical deformations
Solution Approach 1:
The intermediate transfer unit serves as a mediator that decouples the inspection system from the vibrating printing environment, allowing the use of high-precision line-scan cameras without suffering from vibration-induced optical deformations
Solution Approach 2:
The patent replaces the traditional matrix-type camera system with a line-scan camera system that offers superior manufacturing precision and image quality, while using the intermediate transfer unit to eliminate the mechanical vibration problem
3Productivity
If in-line inspection is implemented directly on the printing press, then productivity is improved by real-time monitoring, but inspection accuracy deteriorates due to interference from printing vibrations
Solution Approach 1:
The intermediate transfer unit enables real-time in-line inspection by continuously transporting sheets from the printing press to the inspection system, maintaining productivity while the isolation from vibrations ensures high inspection accuracy
Solution Approach 2:
The intermediate transfer unit prepares and positions sheets in advance at the inspection location, allowing the line-scan camera to capture images at optimal moments when vibration interference is minimized, thus maintaining both real-time monitoring and high accuracy
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
Enables effective in-line inspection of printed material on intaglio printing presses using line-scan cameras, avoiding interference from vibrations and ensuring high-resolution images without optical aberrations, thus improving the inspection process's reliability and accuracy.
Implementation Method 1
a curved suction surface for holding a backside of the sheet against the curved suction surface
Data Source
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AI summary
There is described an inspection system (50) for in-line inspection of sheet or web material on an intaglio printing press, wherein the inspection system comprises an optical quality control apparatus for carrying out inspection of a printed area on a printed side of the sheet or web material, the optical quality control apparatus including a camera system (55) with one or more camera units each comprising at least one line-scan camera (56) for scanning and acquiring an image of the printed area while the sheet or web material is being transported in the intaglio printing press past the camera system (55). A location of the at least one line-scan camera (56) in the intaglio printing press along a delivery path of the sheet or web material is such that cyclical vibrations that spread periodically throughout the intaglio printing press during operation of the intaglio printing press do not occur while the camera system (55) is scanning the printed area of the sheet or web material and acquiring a complete image of the printed area.