Photosensitive Printing Plate Floor Thickness Control

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Solution Overview

Problem

Existing printing processes face variability in plate quality due to undefined time delays between exposure steps, leading to inconsistent dot sizes and stability issues in printed elements.

Innovation Solution

An apparatus and method that involve sequentially exposing the back side and then the front side of a photosensitive printing plate to radiation, with a precisely defined and repeatable time delay between exposures, ensuring that each radiation step provides only a fractional amount of the total exposure, and repeating these steps until the desired total radiation is achieved, while optimizing the time delay for optimal dot size and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If simultaneous front and back exposure is used, then productivity is improved, but manufacturing precision deteriorates due to inability to control floor thickness independently

Engineering Contradiction:
Improveexposure efficiencyVSAvoidfloor thickness control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The exposure process is segmented into distinct stages: first back-side exposure to form the floor, then front-side exposure to create the image. This segmentation allows independent control of floor thickness and image quality, resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The back-side exposure is performed as a preliminary action before front-side exposure. By pre-forming the floor structure through back exposure, the subsequent front exposure can focus solely on image creation without interfering with floor thickness, thus maintaining both efficiency and precision.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If variable time delay between exposure steps is used, then ease of operation is improved, but manufacturing precision deteriorates due to unpredictable plate quality

Engineering Contradiction:
Improveprocess flexibilityVSAvoidplate quality consistency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The time delay between back-side and front-side exposure is changed from a variable parameter to a controlled parameter with optimized values. By establishing specific time delay ranges (e.g., 1-30 seconds), the process maintains operational flexibility while ensuring consistent plate quality and predictable manufacturing outcomes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If smaller printing plate elements are used to reduce dot size, then manufacturing precision is improved, but reliability deteriorates due to increased susceptibility to damage

Engineering Contradiction:
Improvedot size controlVSAvoidelement stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Different regions of the printing plate are given different properties through selective exposure: the floor area receives optimized back-side exposure for stability and durability, while the image areas receive front-side exposure for precise dot formation. This local quality differentiation allows small, precise dots while maintaining overall element reliability.

Inventive Principle:
Principle #3Local quality

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 results in smaller, more stable print dots with improved printing quality by optimizing the time delay between back and front exposures, minimizing variability and enhancing the precision of printed details.

Implementation Method 1

a photosensitive polymer activated by exposure to radiation

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3583470B1Process and apparatus for adjusting the floor of a flexographic printing plate in a controlled exposure system or process
Publication Date: 2022.09.21 ESKO GRAPHICS IMAGING
  • EP3583470B1 patent drawingFigure 1A
  • EP3583470B1 patent drawingFigure 1B
  • EP3583470B1 patent drawingFigure 2A~2B

AI summary

A method and apparatus to expose photosensitive printing plates with a predetermined radiation density from the main side (top) and a predetermined radiation density from the back side (bottom). The method comprises executing the main exposure with a time delay after the back exposure. The time delay between back exposure and main exposure is optimized to create smaller stable single dot elements on the photosensitive printing plate after processing and smaller single element dot sizes printed on the print substrate. The plate floor is adjusted by performing a back-side-only exposure prior to executing the combined back and main exposure with the time delay.