Security Document Sheet Sorting by Defect Severity
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Solution Overview
Problem
Conventional methods for producing security documents fail to effectively identify and manage defects in substrate materials, leading to unnecessary waste as security printers process defective sheets without prior knowledge of their quality.
Innovation Solution
A method and installation for processing substrate webs into individual sheets, which includes inspecting the sheets for quality, applying security features, providing identifying codes, and sorting sheets into grade-A, grade-B, and grade-C stacks based on defect severity, allowing for optimized production and clear quality indication to security printers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate material is produced and supplied in conventional form without inspection, then production continuity is maintained, but defects remain undetected leading to waste
Solution Approach 1:
The patent implements inspection systems that examine substrate material before it reaches the security printer, enabling early detection of defects. This preliminary action allows defective sheets to be identified and separated before processing, preventing waste while maintaining production continuity.
Solution Approach 2:
The patent establishes a feedback mechanism where inspection results are communicated back to the production process. Quality information about substrate defects is fed back to enable real-time adjustments and proper sorting, ensuring that only合格 materials proceed to printing while defective ones are diverted.
2Measurement precision
If inspection systems are implemented to check substrate quality, then defect detection improves, but process complexity increases
Solution Approach 1:
The patent divides the inspection process into multiple stages and locations along the substrate production and distribution chain. Different inspection systems are placed at strategic points (e.g., during web production, before winding, before delivery) to detect defects at various levels, making the overall complex system manageable through modular segmentation.
Solution Approach 2:
The patent employs inspection systems that serve multiple functions: detecting various types of defects (visual, dimensional, material properties), classifying defect severity, and providing sorting guidance. This multi-functionality reduces the need for separate specialized systems for each inspection task.
3Productivity
If all sheets are processed by security printers without quality sorting, then production efficiency is maintained, but defective sheets cause rework and waste
Solution Approach 1:
The patent implements preliminary sorting of substrate sheets based on inspection results before they reach the security printer. Sheets are pre-categorized into acceptable and defective groups, ensuring that only suitable materials enter the printing process. This prevents rework and waste while maintaining high production efficiency for合格 materials.
Solution Approach 2:
The patent converts the potentially harmful effect of defective sheets (waste and rework) into a benefit by using the inspection and sorting process to identify and separate defective materials. The sorting mechanism transforms what would be wasted resources into a structured quality control process that improves overall production efficiency.
4Productivity
If substrate defects are not identified prior to printing, then production flow is uninterrupted, but quality issues arise after processing
Solution Approach 1:
The patent performs quality inspection and sorting actions before the printing process begins. By detecting and separating defective sheets in advance, the system ensures that only high-quality substrates enter the printing workflow, guaranteeing print quality without interrupting the overall production flow of合格 materials.
Solution Approach 2:
The patent introduces an intermediary quality control system between substrate production and printing processes. This intermediary inspection and sorting mechanism acts as a buffer that filters out defective materials, allowing the printing process to operate continuously with guaranteed input quality, thus maintaining both productivity and manufacturing precision.
Data Source
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AI summary
There is described a method of processing a substrate web (W) into individual sheets (S) for the production of security documents, such as banknotes, the method comprising the following steps: a) providing a substrate web (W) ; b) inspecting the substrate web (W) to check a quality thereof; c) cutting the substrate web (W) into individual sheets (S) ; d) sorting the individual sheets (S) in dependence of results of the inspection at step b) to produce at least two types of sorted sheets (SA, SB, SC), including good sheets (SA) meeting desired quality requirements and bad sheets (SB, SC) that are found to exhibit defects ; and e) processing at least the good sheets (SA), and preferably also the bad sheets (SB, SC), into individual stacks or reams (R, RW) each consisting of a predetermined number of individual sheets. Also described is an installation for carrying out this method.