Flexographic Printing Plate Precursor Exposure Control
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Solution Overview
Problem
Current water-developable flexographic printing plate precursors exhibit excellent rear end ink receptivity but insufficient microcell reproducibility, particularly in forming fine concave-convex structures with depths of 10 μm or less.
Innovation Solution
A flexographic printing plate precursor comprising a support and a photosensitive layer with specific composition and exposure conditions, including a back exposure amount of 600 μm and a main exposure amount of 4 μm for a 200 μm convex thin line, satisfying conditions R=(Ef/Eb)×(t−0.6)/0.54 between 12 and 30, and Ef being 5,000 or more, with a monomer and photopolymerization initiator content ratio within 15≤M×I1/2≤28, and containing non-fluid rubber and polymerization inhibitor within specified ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a water-developable photosensitive resin plate is used to improve the working environment and global environment, then rear end ink receptivity is improved, but microcell reproducibility becomes insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the exposure amounts (back exposure Eb and main exposure Ef) and their ratio R, along with the thickness t of the printing plate precursor. By adjusting these parameters to satisfy specific mathematical relationships, the patent achieves both excellent rear end ink receptivity and microcell reproducibility in water-developable photosensitive resin plates.
Solution Approach 2:
The patent uses composite materials by formulating a photosensitive layer containing water-dispersible particles, binder, monomer, photopolymerization initiator, and polymerization inhibitor. This composite composition enables the plate to achieve both good rear end ink receptivity and microcell reproducibility through the synergistic effects of different materials.
2Manufacturing precision
If the exposure amount is increased to improve microcell reproducibility, then fine concave-convex structure formation is improved, but rear end ink receptivity may deteriorate
Solution Approach 1:
The patent applies preliminary action by performing back exposure before the main exposure. This preliminary exposure creates a specific relief depth (600 μm) that prepares the plate structure for subsequent main exposure, ensuring that both microcell reproducibility and rear end ink receptivity are optimized through the pre-established structural foundation.
Solution Approach 2:
The patent uses periodic action by dividing the exposure process into two distinct stages: back exposure (Eb) and main exposure (Ef). By controlling the ratio and sequence of these periodic exposure actions, the patent achieves optimal balance between microcell reproducibility and rear end ink receptivity.
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 achieves excellent rear end ink receptivity and microcell reproducibility, enhancing the printed article's density and ink transfer quality while maintaining water-based ink resistance and development scum dispersibility.
Implementation Method 1
a photosensitive layer disposed above the support, in which the photosensitive layer contains at least water-dispersible particles, a binder, a monomer, a photopolymerization initiator, and a polymerization inhibitor
Data Source
AI summary
An object of the present invention is to provide a flexographic printing plate precursor which exhibits excellent rear end ink receptivity and microcell reproducibility in a case of being used for a flexographic printing plate. The flexographic printing plate precursor of the present invention includes a support and a photosensitive layer disposed above the support, in which all of the following conditions A and B are satisfied.Condition A: in a case where R=(Ef/Eb)×(t−0.6)/0.54, a value of R is 12 or more and 30 or less,Condition B: Ef is 5,000 or more,Here,Eb is a back exposure amount (unit: mJ/square centimeter), and refers to an exposure amount at which a relief depth is 600 μm,Ef is a main exposure amount (unit: mJ/square centimeter), and refers to an exposure amount at which a difference in height between an end part as a convex portion and a central part as a concave portion in a case of forming an image area consisting of a 200 μm convex thin line reaches 4 μm, andt refers to a thickness of the flexographic printing plate precursor from a bottom surface of the support to a surface of the photosensitive layer.