Security Paper Color Features from Localized Wet-Web Dye Application

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Solution Overview

Problem

Existing methods for incorporating security features on security paper are inefficient and lack flexibility in design, making it difficult to produce security paper with customized and efficient security features.

Innovation Solution

A method involving a non-contact dye application process during the papermaking process, applying dye to a pre-dried intermediate product of the security paper, allowing for localized and controlled formation of colored security features before final drying, using techniques like inkjet printing or wide ink jets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If security features are applied after paper production, then the security paper can be produced in standard processes, but the security feature application becomes a separate inefficient step

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the security feature application process with the papermaking process by integrating the dye application device into the paper machine. The dye is applied to the paper web during the formation stage, merging two previously separate operations (paper production and security feature application) into a single integrated process, thereby improving productivity without significantly increasing overall process complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The security features are applied in advance during the papermaking process rather than as a subsequent step. The dye is applied to the wet or partially dried paper web while it is still on the forming fabric, performing the security feature application preliminarily before the paper is completely dried and finished, thus eliminating the need for a separate post-production application step

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If conventional security features are used, then production is straightforward, but design flexibility and customization are limited

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent employs a dynamic dye application system where the dye application can be controlled and adjusted during the papermaking process. The dye application device can be programmed to create various patterns, colors, and designs on the paper web, allowing for flexible customization of security features while maintaining ease of manufacture through automated control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The dye is applied locally to specific areas of the paper web rather than uniformly across the entire sheet. This localized application allows for creating specific security patterns, logos, or features in predetermined locations, providing design flexibility while maintaining manufacturing simplicity through targeted application

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If dye is applied to completely dried paper, then the paper structure is stable, but dye absorption and feature formation are poor

Engineering Contradiction:
Improvefeature formation qualityVSAvoidpaper structure stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The dye application is performed preliminarily while the paper is still wet or partially dried on the forming fabric, before the paper structure is completely stabilized. This timing allows the dye to be absorbed effectively by the porous wet paper structure, ensuring good feature formation quality while the paper is still in a receptive state

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent exploits the changing physical parameters of the paper during the drying process. The paper transitions from a wet, porous state with high dye absorption capability to a dried, stable state. By applying the dye during the transition phase when the paper is partially dried, the system takes advantage of the intermediate state that provides both adequate absorption and structural stability

Inventive Principle:
Principle #35Parameter changes

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 the production of security paper with individually designed color security features that can be efficiently integrated into various security documents, providing enhanced security and design flexibility.

Implementation Method 1

a dye is applied at least locally to a pressed and pre-dried, not yet completely dried, intermediate product of the security paper

Methodology Applied
Scientific EffectAbsorption (physical): Absorption (physical)

Data Source

PatentEP3704304B1Method for producing a security feature on a security paper, and use thereof
Publication Date: 2025.08.27 BUNDESDRUCKEREI GMBH
  • EP3704304B1 patent drawingFigure 1
  • EP3704304B1 patent drawingFigure 2

AI summary

The invention relates to a method for producing a security feature on a security paper, in which method a security paper (1) is generated by means of a paper production process and thereby a colour security feature (6) is designed on the security paper (1), wherein, in order to design the colour security feature (6), a colouring agent is applied during the paper production process at least locally to an intermediary product (5) of the security paper by means of a colour application method, said intermediary product being not yet dried or not yet completely dried, and the intermediary product (5) is subsequently dried or further dried. The invention also relates to the use of a produced security paper having the security feature in order to produce a security document.