Pivotable Foil-Guiding Elements for Detachment Control
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Solution Overview
Problem
Existing methods and devices for coating printing materials with foil are complex and do not adequately account for varying detachment behaviors of different foils, printing materials, or types of varnish or glue, leading to inefficiencies and potential collisions with grippers.
Innovation Solution
A method and device that involve changing the path or angle of the foil relative to the counter-surface using switchable foil-guiding elements, such as pneumatically activatable or pivotable guide rollers, to control the detachment behavior of the foil from the printing material, allowing for different foil paths and angles of detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed foil-guiding elements are used to guide the foil through the transfer nip, then the foil path is stable and consistent, but the device cannot adapt to different detachment behaviors of different foils, printing materials, or varnish types
Solution Approach 1:
The foil-guiding element is made dynamically adjustable through a pivotable mounting mechanism that allows changing the guide angle relative to the impression cylinder. This enables adaptation to different detachment behaviors of various foil and material combinations without requiring multiple fixed guiding systems.
Solution Approach 2:
The guide angle parameter of the foil-guiding element can be changed to optimize foil detachment for different materials. By adjusting this geometric parameter, the system adapts to varying detachment requirements while maintaining a single guiding element structure.
2Duration of action of stationary object
If the foil is guided over a longer distance on the impression cylinder to allow UV drying, then the varnish has sufficient time to harden, but the foil may collide with grippers holding the printing material
Solution Approach 1:
The foil-guiding element can be pivoted to different angular positions to create different foil paths along the impression cylinder. This dynamic adjustment allows selecting a path length that provides sufficient UV drying time while avoiding collision zones occupied by grippers.
Solution Approach 2:
Instead of only extending the foil path in the circumferential direction of the cylinder, the system uses angular adjustment of the guiding element to change the path geometry in a different dimensional aspect, achieving both drying time and collision avoidance.
3Object-affected harmful factors
If the foil-guiding element is disengaged from the counter-surface to avoid collisions, then gripper interference is eliminated, but precise control over foil detachment behavior is lost
Solution Approach 1:
The foil-guiding element maintains engagement with the counter-surface through a pivotable connection that allows angular adjustment while preserving continuous contact. This enables precise control of foil detachment through angle variation without complete disengagement, combining both precision and collision avoidance.
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
This approach enables more precise control over the detachment of the foil, improving the quality of the coating process by adapting to different materials and preventing collisions with grippers, thus enhancing the efficiency and effectiveness of the coating operation.
Implementation Method 1
pneumatically activatable or pivotable guide rollers
Implementation Method 2
The transfer layer is detached from the carrier and is transferred to the printing material under pressure in the areas that are coated with glue
Implementation Method 3
The hardening is achieved by using UV varnish and a UV drier above the web of foil
Data Source
AI summary
A device and a method for coating a printing material include a foil engaged with a printing material on an impression cylinder using guide rollers. The foil and the printing material are guided together in an engagement area and a functional layer, such as glue or varnish, is dried, i.e. activated or polymerized, through the foil in the engagement area using a drier. The guide rollers are disengaged from the impression cylinder to avoid contact between the foil and grippers of the impression cylinder. To improve a detachment behavior of the foil from the functional layer, an angle of detachment between the foil and the sheet is varied by pivoting the guide rollers about an external geometrical pivot axis or an internal geometrical pivot axis, or at least assisting the disengagement of the foil from the impression cylinder by a change of a pneumatic condition of a foil-guiding element.