Negative Planographic Plate Precursor for Visible On-Press Development

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Solution Overview

Problem

Existing planographic printing plate precursors lack sufficient visibility of exposed portions and durability during on-machine development, particularly in UV printing, and generate environmental waste from wet development treatments.

Innovation Solution

A planographic printing plate precursor with an image-recording layer containing an electron-accepting polymerization initiator, an infrared absorber, and a color-developing substance precursor, which is exposed to an infrared laser for on-machine development, ensuring a brightness change of 3.0 or more and utilizing a leuco colorant with phthalide structure and electron donating groups for enhanced visibility and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If an on-machine development type planographic printing plate precursor is used to eliminate wet development treatments, then environmental waste is reduced, but visibility of exposed portions and durability during UV printing are insufficient

Engineering Contradiction:
Improveenvironmental waste from wet developmentVSAvoiddurability during UV printing
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the image-recording layer by incorporating specific components: an electron-accepting polymerization initiator, an infrared absorber capable of donating electrons, and a color-developing substance precursor. These parameter changes enable the layer to undergo photoinduced electron transfer upon infrared exposure, creating visible color changes and ensuring durability during UV printing without requiring wet development treatments.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system in the image-recording layer that combines multiple functional components: the electron-accepting polymerization initiator, the infrared absorber with electron-donating capability, and the color-developing substance precursor. This composite structure enables simultaneous achievement of infrared sensitivity, visible exposure patterns, and printing durability, resolving the contradiction between eliminating wet development and maintaining reliability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional planographic printing plate precursors are used with wet development, then durability is maintained, but environmental waste is generated and the process complexity increases

Engineering Contradiction:
Improvedurability during printingVSAvoidprocess complexity including wet development
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the wet development treatment step from the conventional plate making process. By incorporating the color-developing substance precursor and electron-donating infrared absorber directly in the image-recording layer, the patent enables the development function to occur automatically during infrared exposure, removing the need for separate wet development equipment and procedures while maintaining durability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The image-recording layer is designed to perform self-development through the photoinduced electron transfer mechanism. Upon infrared laser exposure, the electron transfer between the infrared absorber and polymerization initiator triggers color development and polymerization reactions that create the final printing plate structure, enabling the system to serve itself without external wet development intervention.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the image-recording layer contains components for on-machine development, then wet treatment is minimized, but visibility and durability are insufficient without specific component optimization

Engineering Contradiction:
Improveminimization of wet treatmentsVSAvoidvisibility and durability of exposed portions
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by designing the infrared absorber with specific electron-donating groups positioned to interact with the electron-accepting polymerization initiator at exposure sites. This localized electron transfer capability ensures that color development and polymerization occur precisely where infrared light is applied, achieving high visibility and durability without wet treatments while maintaining ease of manufacture.

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

The solution provides improved visibility and durability of the exposed portions, enabling effective on-machine development and reducing environmental waste by minimizing wet treatments.

Implementation Method 1

the image-recording layer contains an electron-accepting polymerization initiator, an infrared absorber capable of donating electrons to the initiator

Methodology Applied
Scientific EffectPhotoinduced electron transfer: Photoelectric Effect

Implementation Method 2

an infrared absorber capable of donating electrons to the initiator, and a color-developing substance precursor, in a case where the image-recording layer is exposed to an infrared laser with a wavelength of 830 nm

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentEP4349602B1On-machine development type negative planographic printing plate precursor, method for preparing a planographic printing plate, and planographic printing method
Publication Date: 2025.11.12 FUJIFILM CORP
  • EP4349602B1 patent drawingFigure 1~2B
  • EP4349602B1 patent drawingFigure 3A~3B
  • EP4349602B1 patent drawingFigure 4A~4B

AI summary

Provided is an on-machine development type planographic printing plate precursor having a support and an image-recording layer on the support, in which the image-recording layer contains an initiator, an infrared absorber capable of donating electrons to the initiator, and a color-developing substance precursor, the image-recording layer can form an image by exposure to infrared laser, and in a case where the image-recording layer is exposed to an infrared laser with a wavelength of 830 nm at an energy density of 110 mJ/cm2, a brightness change ΔL of the image-recording layer before and after the exposure is 3.0 or more. Also provided are a method for preparing a planographic printing plate or a planographic printing method in which the on-machine development type planographic printing plate precursor is used.