Flexographic Plate Photoexposure Device Direct UV Light
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Solution Overview
Problem
Conventional methods for producing flexographic plates result in print points with rounded contours due to exposure to diffuse ultraviolet light, leading to reduced print quality.
Innovation Solution
A method involving a digital photopolymer plate coated with a protective layer of black graphite, followed by laser ablation and exposure to direct ultraviolet light using a combination of neon tubes and metal halogen lamps, with a permeable oxygen-blocking film to optimize polymerization, ensuring sharp contours and improved print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If exposure to diffuse ultraviolet light is used, then the polymerization process is simplified, but the print points acquire rounded contours reducing print quality
Solution Approach 1:
The patent segments the light source into two distinct types: direct UV light sources (metal halogen lamps) and diffuse UV light sources (neon tubes). By spatially separating and controlling these two types of light sources independently, the system achieves both sharp print point contours (from direct light) and complete polymerization (from diffuse light), resolving the contradiction between manufacturing simplicity and precision.
Solution Approach 2:
The patent applies different lighting conditions to different spatial zones: direct UV light is concentrated on the print point areas to ensure sharp contours, while diffuse UV light covers the entire plate surface to ensure complete polymerization. This local differentiation of light quality resolves the contradiction between sharpness and completeness.
2Manufacturing precision
If direct ultraviolet light is used for exposure, then sharp print point contours are achieved, but incomplete polymerization occurs
Solution Approach 1:
The patent merges two previously separate exposure processes into a single unified exposure step. By combining direct UV light sources (for sharpness) and diffuse UV light sources (for completeness) into one exposure system operating simultaneously, the patent achieves both sharp contours and complete polymerization in one go, eliminating the need for sequential processing.
Solution Approach 2:
The exposure device is designed with multi-functionality: it can provide both direct and diffuse UV illumination simultaneously, and can independently control each type of light source. This universal exposure system handles both the sharpness requirement and the completeness requirement within a single device, resolving the contradiction between precision and reliability.
3Manufacturing precision
If conventional washing with solvents is performed, then non-polymerized material is removed, but production downtime increases
Solution Approach 1:
The patent extracts and removes the washing step entirely from the manufacturing process. By using a water-soluble photopolymer composition that can be rinsed with water instead of requiring solvent-based washing, the system achieves plate cleanliness with a much faster, simpler water rinse operation, significantly reducing production downtime while maintaining precision.
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 method produces flexographic plates with print points having flat heads and sharp contours, enhancing print quality by preventing ink smudging and adapting better to printing imperfections on flexible and rigid materials, while reducing production and maintenance costs.
Implementation Method 1
a step of ablation by means of a laser, according to the graphic element to be provided
Implementation Method 2
the plates are cured where the graphite has been removed because, since the graphite is no longer present, the ultraviolet rays can strike the plates, initiating polymerization
Data Source
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AI summary
The present invention relates to a method for providing flexographic plates, particularly for flexographic printing systems, comprising the following steps: - first surface coating of a digital photopolymer plate (1) with a layer of protective material (2) that is impermeable to ultraviolet rays, - ablating by means of a laser device (3) according to a preset graphic element the digital photopolymer plate (1) in order to remove the layer of protective material (2) in a manner that corresponds to the print points that define said graphic element, - exposing, by means of one or more light sources (8), the digital photopolymer plate (1) for its polymerization in a manner that corresponds to the previously ablated regions (16), - washing the polymerized digital photopolymer plate (1) for removal of the non-ablated regions (11) of the digital photopolymer plate (1), - finishing the digital photopolymer plate (1) by means of an exposure to ultraviolet rays to complete the polymerization of the digital photopolymer plate (1). In the exposure step the digital photopolymer plate (1) is exposed to a light source (8) adapted to generate ultraviolet light at least of the direct type by means of a photoexposure device (50).