Security Paper Stiffened Watermark with Overlapping Element
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Solution Overview
Problem
Existing security papers with paper-stiffening watermarks face limitations in integrating additional security elements due to increased paper thickness, leading to poor stacking behavior and uneven ink application during printing.
Innovation Solution
A security paper design featuring a paper-stiffening watermark with a plateau area and an outlet area where the paper thickness decreases, allowing security elements to overlap only in the outlet area, ensuring good adhesion and improved stacking while maintaining paper stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If paper-stiffening watermarks are used to strengthen banknotes, then the rigidity and stacking properties are improved, but the paper thickness increases which limits the placement of additional security elements
Solution Approach 1:
The paper-stiffening watermark is designed with non-uniform thickness distribution, featuring a thicker plateau area for structural strength and a thinner run-out area for element placement. This local differentiation allows the watermark to provide rigidity where needed while maintaining adaptability for security element integration in the run-out area.
2Reliability
If security elements are placed on top of paper-stiffening watermarks, then authentication features are enhanced, but the local increase in paper thickness results in poor stacking properties
Solution Approach 1:
The watermark structure creates a local thickness gradient where the run-out area provides a thinner substrate for security element placement. This local quality variation allows authentication elements to be added without causing excessive thickness accumulation that would deteriorate stacking properties.
Solution Approach 2:
The solution moves from a uniform two-dimensional watermark approach to a three-dimensional structure with varying thickness. By utilizing the vertical dimension (thickness variation) within the watermark itself, the design accommodates additional security elements while maintaining overall stacking performance.
3Strength
If conventional paper-stiffening watermarks are used with rotary screen printing, then the watermarks provide structural reinforcement, but the high thickness fluctuations cause uneven ink application
Solution Approach 1:
The watermark is designed with distinct functional zones: the plateau area provides structural reinforcement with higher thickness, while the run-out area with lower thickness ensures uniform ink application. This local quality differentiation resolves the contradiction between structural strength and printing precision.
Data Source
Figure 1~2
Figure 3~5(d)
AI summary
The invention relates to a security paper (12) for the production of security or valuable documents, comprising a vellum area (14), a paper-stiffening watermark (20) formed by an area with increased paper thickness compared to the vellum area, and a security element (28) overlapping the paper-stiffening watermark (20). According to the invention, the paper-stiffening watermark (20) includes a plateau area (22) in which the increased paper thickness has a maximum value, and a trailing area (24) adjoining the plateau area (22) in which the paper thickness is reduced compared to the maximum value of the plateau area (22), wherein the security element (28) overlaps the paper-stiffening watermark (30) essentially only in the trailing area (24).