Convex Coating Roller for Fine Line Pigment Application
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Solution Overview
Problem
Existing methods for applying iridescent pigments on substrates, such as security documents, are limited in the number of fine, adjacent lines that can be applied and suffer from inadequate control over application quantity and stripe width, particularly due to temperature-dependent viscosity issues.
Innovation Solution
A device with a convex surface area and controllable passage openings allows for precise application of a large number of fine lines by adjusting the angle of attack, which compensates for viscosity changes and ensures consistent application, enabling the creation of complex color codes and security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual pipette-like devices are used to apply pigmented color to an application roller, then the application process can be performed, but the number of individual strips that can be applied in direct proximity is limited and their width cannot fall below a certain level
Solution Approach 1:
The application roller is segmented into multiple independently controllable sections, each capable of receiving and applying different pigmented colors. This segmentation allows multiple narrow strips to be applied simultaneously in direct proximity without interfering with each other, thereby increasing both the number of strips and reducing the minimum achievable width.
Solution Approach 2:
The invention transitions from applying strips sequentially in one dimension to applying multiple strips simultaneously across the width of the substrate in another dimension. The application roller contacts the substrate web along its width, enabling parallel application of multiple colored strips, thus increasing productivity while maintaining fine stripe width.
2Manufacturing precision
If a roller is used to apply pigmented color to the substrate web, then the application process can be performed, but the application quantity and stripe width cannot be sufficiently controlled
Solution Approach 1:
The application roller is designed with dynamically adjustable parameters including variable rotation speed for each segment, adjustable contact pressure with the substrate web, and controllable pigment supply rates. These dynamic controls enable precise regulation of application quantity and stripe width while compensating for temperature-dependent viscosity changes, thereby improving both manufacturing precision and process stability.
Solution Approach 2:
The system allows independent adjustment of multiple parameters including pigment viscosity, application roller surface speed, contact pressure, and segment rotation rates. By dynamically changing these parameters, the invention achieves precise control over application quantity and stripe width while maintaining process stability despite environmental variations.
3Adaptability or versatility
If the pigments are applied with temperature-dependent viscosity, then the pigments can be applied, but the application process becomes difficult to control in terms of application quantity and stripe width
Solution Approach 1:
The system incorporates feedback mechanisms that monitor pigment viscosity and application parameters in real-time. Based on this feedback, the control system automatically adjusts roller speed, contact pressure, and pigment supply rates to compensate for temperature-dependent viscosity changes, thereby maintaining consistent application quantity and stripe width across varying temperatures.
Solution Approach 2:
The invention compensates for temperature-dependent viscosity by dynamically adjusting operational parameters such as roller rotation speed, contact pressure, and pigment flow rate. When temperature increases causing viscosity to decrease, the system reduces speed or pressure to maintain consistent application, and vice versa, thereby preserving manufacturing precision across different temperature conditions.
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 device enables the precise application of numerous fine lines in different colors, enhancing security features by providing high edge sharpness and optical effects, while maintaining process stability despite temperature variations.
Implementation Method 1
the application quantity depends on the lowest height of the gap essentially at the contact line between the paper web and the coater head contour
Data Source
Figure 1
Figure 2a~3b
Figure 4~5
AI summary
The invention relates to a device (1) for applying a color to a substrate web (3) guided past the device (1) along a running direction (12). The device is characterized in that it comprises a surface region (28) that is designed convex in the running direction (12) and linear perpendicular to the running direction (12), which region can be brought in contact with the substrate web (3), and the convexly designed surface region (28) is provided with one passage, preferably at least two passages (6) for the color, which can be controlled separately in terms of the color and are offset in a direction perpendicular to the running direction (12), and through which the color is directly applied to the substrate web (3), wherein the application quantity of the color is dependent on the angle of attack (13-15) between the plane of the substrate web (3) and the normal to a tangential plane at the surface region (28) at the site of the respective passage (6).