Dewatering Screen with Plastic Watermark Insert for Security Paper
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Solution Overview
Problem
Existing dewatering screens for paper production do not effectively combine robustness, security against forgery, and attractive visual appearance, particularly for security papers like banknotes, which require both physical reinforcement and distinctive watermarks.
Innovation Solution
A dewatering sieve with a paper-stiffening watermark is developed, featuring elongated depressed areas on a hydrophobic plastic insert with a fine structure that appears bright in transmitted light, integrated into a carrier screen to create areas of increased paper thickness, providing both rigidity and security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional dewatering screens are used for paper production, then the production process is simple and cost-effective, but the resulting paper lacks robustness, resistance to creases and folds, and security features
Solution Approach 1:
The dewatering screen is segmented into multiple functional layers: a supporting screen structure and a plastic watermark insert with depressed regions. This segmentation allows the screen to simultaneously provide structural support and create paper-stiffening watermarks, resolving the contradiction between simplicity and enhanced paper properties.
Solution Approach 2:
The invention uses a composite structure combining a supporting screen (metal or plastic mesh) with a plastic watermark insert made of hydrophobic material. This composite design enables the dewatering screen to impart both mechanical strength and security features to the paper without significantly complicating the overall structure.
2Reliability
If watermarks are added to security papers for authentication, then security against counterfeiting is improved, but the visual appearance and attractiveness are compromised
Solution Approach 1:
The plastic watermark insert creates optical effects through its depressed regions and motif elements, producing bright appearances in transmitted light. The hydrophobic plastic material and specific geometric structures (elongated depressed regions with motif elements) generate attractive visual patterns that simultaneously provide security features, resolving the contradiction between security and aesthetics.
3Stability of the object's composition
If thickened paper areas are created for watermarks to strengthen banknotes, then rigidity is improved, but the paper becomes more susceptible to folding and creasing at the thickened areas
Solution Approach 1:
The plastic watermark insert creates localized thickened areas with depressed regions and motif elements that provide rigidity where needed. The elongated depressed regions (length-to-width ratio of 5 or more) with controlled dimensions (width ≤ 2.5 mm) create strategic reinforcement zones that strengthen the banknote while minimizing fold susceptibility through their specific geometry and distribution.
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
The solution enhances the rigidity and security of paper products by creating visible, bright fine structures within thickened areas, making them resistant to bends and folds while preventing unauthorized reproduction.
Implementation Method 1
a fine structure which appears bright in transmitted light
Implementation Method 2
The dewatering screen can also have a plastic overmolding or backmolding that connects the watermark insert to the supporting screen
Data Source
Figure 1~2
Figure 3~5
Figure 6~7b
AI summary
The invention relates to a dewatering screen (40) for the production of paper (10) with a paper-stiffening watermark (12, 14), wherein, according to the invention, the paper-stiffening watermark (12, 14) is provided in the form of at least one area of increased paper thickness (20, 24), within which a watermark fine structure (22, 26), appearing bright in transmitted light, is present in the form of patterns, characters, or a code. The dewatering screen (40) has a carrier screen (42) with a screen surface (52) on which paper is deposited, and a perforated plastic watermark insert (60) arranged in a partial area of the carrier screen (42).The plastic watermark insert (60) has at least one recessed area (62) below the screen surface (52) for the production of the paper-stiffening watermark (12), in the interior of which motif elements (66) protruding from the recessed area (62) with a characteristic dimension of 0.6 mm or less are arranged in the form of patterns, characters or a code, which serve to produce the watermark fine structure (22).