UV LED Printing Plate Cooling to Prevent Thermal Polymerization

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Solution Overview

Problem

Existing curing methods for flexographic printing plates fail to efficiently prevent thermal polymerization during UV exposure, leading to unwanted broadening of small features and distortion of tone curves due to inadequate cooling arrangements.

Innovation Solution

A system and method that directs cooling air from the trailing edge of the radiation source to the leading edge during UV exposure, utilizing a controlled airflow system to maintain optimal temperature and prevent thermal polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cooling air is directed from the leading edge to the trailing edge of the radiation source, then the cooling system is simpler to implement, but thermal polymerization increases causing feature broadening and tone curve distortion

Engineering Contradiction:

Improvecooling system implementationVSAvoidfeature dimensions and tone curves

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional cooling air flow direction by directing cooling air from the trailing edge to the leading edge of the radiation source, opposite to the direction of source movement. This inversion creates a cooling boundary layer that prevents thermal polymerization, thereby maintaining manufacturing precision while still using a relatively simple cooling system implementation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Object-affected harmful factors

If cooling air volume is increased to prevent thermal polymerization, then thermal polymerization is reduced, but energy consumption and system complexity increase

Engineering Contradiction:

Improvethermal polymerizationVSAvoidcooling air energy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter of cooling air flow direction from the conventional leading-edge-to-trailing-edge direction to the opposite direction (trailing edge to leading edge). This parameter change optimizes the cooling efficiency, allowing effective prevention of thermal polymerization with moderate air volume, thereby reducing energy consumption compared to simply increasing air volume in the conventional direction.

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If UV LED sources with larger radiation-emitting lateral dimension are used, then curing coverage is improved, but thermal polymerization risk increases

Engineering Contradiction:

Improvecuring coverage areaVSAvoidthermal polymerization

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs pneumatic cooling by directing a controlled volume of cooling air through the gap between the radiation source and the printing plate. This pneumatic cooling system effectively removes heat from the photopolymer during exposure, preventing thermal polymerization even when using UV LED sources with larger radiation-emitting lateral dimensions that provide broader curing coverage.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 effectively reduces thermal polymerization, maintaining precise feature dimensions and tone curves by optimizing cooling efficiency, particularly with UV LED sources.

Implementation Method 1

a cooling air handling system configured to direct a volume of cooling air into the gap between the radiation source and the printing plate only in a direction from the trailing edge to the leading edge

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

curing flexographic polymer printing plates... exposure to actinic radiation... a photopolymer printing plate curable by exposure to actinic radiation

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4285187B1Printing plate exposure method and apparatus with reduced thermal polymerization

Publication Date: 2026.03.25 ESKO GRAPHICS IMAGING

Figure 1A~1B
Figure 2
Figure 3A

AI summary

Systems and methods for curing a photopolymer printing plates. A radiation source, such as an UV LED source having a radiation-emitting lateral dimension in a range 10-60 cm, is spaced from a substrate that holds the printing plate. The source and substrate are configured to move relative to one another in a movement direction that defines a leading edge of the radiation source and a trailing edge of the radiation source. A cooling air handling system directs a volume of cooling air into the gap between the radiation source and the printing plate in a direction from the trailing edge to the leading edge. The cooling air handling system may have one or more outlets attached at least one edge of the source, may be configured to only direct air from the trailing edge to the leading edge, or a combination thereof.