Nitrocellulose Lithographic Printing Members with Dual Imaging Layers
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Solution Overview
Problem
Current laser-based lithographic systems face challenges in imaging speed and red-spot formation due to the collapse of nitrocellulose structure when combined with IR-absorbing dyes, leading to inefficient ablation and unwanted voids in printed sheets.
Innovation Solution
Implementing dual adjacent imaging layers, one with an IR-absorptive dye and a binder, and the other with nitrocellulose and an IR-absorptive pigment, to maintain the benefits of high dye loading and nitrocellulose ablation characteristics while avoiding structural collapse, using a melamine resin as a binder and carbon black as the absorber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nitrocellulose is combined with IR-absorbing dyes in a single layer, then the plate can absorb imaging radiation effectively, but the nitrocellulose structure collapses leading to red-spot formation and reduced imaging quality
Solution Approach 1:
The patent divides the imaging system into two separate imaging layers: a first imaging layer containing nitrocellulose and an IR-absorbing pigment, and a second imaging layer containing an IR-absorbing dye. This segmentation prevents the nitrocellulose structure from collapsing while maintaining effective radiation absorption through the combined action of both layers.
2Productivity
If laser power is increased to improve imaging speed, then ablation rate increases, but imaging precision decreases due to excessive energy delivery
Solution Approach 1:
The patent modifies the compositional parameters of the imaging layers by separating nitrocellulose and IR-absorbing dyes into different layers, and by optimizing the ratio of nitrocellulose to binder resin (0.2:99.8 to 50:50). These parameter changes enable effective imaging at lower laser fluence levels, improving both speed and precision.
3Use of energy by moving object
If high dye loading is used to improve radiation absorption, then imaging sensitivity increases, but nitrocellulose structural stability decreases causing red-spot defects
Solution Approach 1:
The patent segments the functional components into separate layers: the first imaging layer contains nitrocellulose with an IR-absorbing pigment, while the second imaging layer contains the IR-absorbing dye. This allows high dye loading in the second layer without compromising nitrocellulose structural stability in the first layer, eliminating red-spot defects while maintaining high imaging sensitivity.
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
Enhances nitrocellulose-containing lithographic printing member performance by reducing or eliminating red-spot areas, allowing for higher imaging speeds and improved durability without impairing layer coatability, and achieving effective ablation at lower fluence levels.
Implementation Method 1
the first imaging layer comprises a binder and a near-IR absorber including a dye, the second imaging layer comprises nitrocellulose and a near-IR absorber that does not include a dye
Implementation Method 2
exposing the printing member to imaging radiation in an imagewise pattern, the imaging radiation at least partially ablating the imaging layers where exposed
Implementation Method 3
using a melamine resin as a binder and carbon black as the absorber
Data Source
AI summary
Dry, ablation-type, nitrocellulose-containing lithographic printing members include dual adjacent imaging layers, both including an absorber and at least one containing a binder (which may include or consist essentially of a melamine resin). The absorber of the nitrocellulose-containing layer is a pigment and this layer contains no absorbing dye, while the absorber of the other imaging layer includes or consists essentially of a dye.