Grained Aluminum Dry Lithographic Plates
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Solution Overview
Problem
In dry lithographic printing, metal substrates with high thermal conductivity pose challenges due to heat dissipation issues, requiring additional heat-insulating layers that complicate manufacturing and increase costs, while plastic substrates lack structural integrity, making them unsuitable for large plates.
Innovation Solution
A dry lithographic printing member is created using a metal sheet with a grained surface, coated with a crosslinked nitrocellulose imaging layer containing an infrared-absorbing dye and an oleophobic silicone or fluoropolymer top layer, eliminating the need for heat-insulating layers and allowing manufacturing on conventional wet-plate coating lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal substrate is used in dry lithographic printing, then structural integrity and rigidity are improved, but heat dissipation becomes excessive causing imaging failures
Solution Approach 1:
The patent applies composite materials by combining a metal substrate (aluminum) with a polymeric heat-insulating layer. This composite structure allows the metal to provide structural integrity and rigidity while the polymer layer provides thermal insulation to prevent excessive heat dissipation during laser imaging, thus resolving the contradiction between strength and heat loss.
Solution Approach 2:
The polymeric heat-insulating layer acts as an intermediary between the metal substrate and the imaging layer. This intermediate layer decouples the thermal conductivity issue by blocking heat transfer from the imaging layer to the metal substrate, allowing the metal to maintain its structural benefits without causing imaging failures due to heat dissipation.
2Loss of energy
If a heat-insulating polymeric layer is added between the base support and imaging layer, then heat dissipation is limited, but manufacturing complexity and cost increase
Solution Approach 1:
The patent makes the polymeric heat-insulating layer serve multiple functions: it provides thermal insulation to control heat dissipation, acts as an adhesion promoter for the imaging layer, and can be applied using conventional wet-plate coating lines. This multi-functionality reduces manufacturing complexity by eliminating the need for separate specialized processes while still achieving heat control.
Solution Approach 2:
The heat-insulating polymeric layer is designed to be self-sufficient by providing both thermal insulation and surface adhesion properties without requiring additional separate layers or complex manufacturing steps. The layer serves its own dual purpose, simplifying the overall plate construction and manufacturing process.
3Stability of the object's composition
If plate thickness is increased to improve rigidity for large plates, then structural stability is improved, but the plate becomes unwieldy and uneconomical
Solution Approach 1:
The patent changes the material parameters by using metal substrates with optimized thicknesses rather than increasing the thickness of polymeric or film-based plates. The metal substrate provides high rigidity and dimensional stability at relatively modest thicknesses, avoiding the need to make plates unwieldly thick while still achieving the necessary structural stability for large plate formats.
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 configuration simplifies the printing member structure, maintains waterless printing performance, and enables the use of metal substrates in dry plates, enhancing manufacturing efficiency and reducing costs by eliminating the need for additional layers.
Implementation Method 1
a polymeric imaging layer consisting essentially of a nitrocellulose composition having dispersed therein an infrared-absorbing dye or pigment
Implementation Method 2
image-wise exposure to imaging (e.g., infrared or 'IR') radiation that causes ablation of all or part of the central layer
Implementation Method 3
roughened, anodized aluminum sheets
Implementation Method 4
when heat-sensitive layers comprising an IR absorber and a crosslinked nitrocellulose composition are utilized in conjunction with roughened, anodized aluminum sheets
Implementation Method 5
an inherently oleophobic (e.g., silicone or a fluoropolymer) top layer
Implementation Method 6
the necessary ink-repellency is provided by an initial application of a dampening fluid to the plate prior to inking
Implementation Method 7
a crosslinked nitrocellulose imaging layer
Data Source
AI summary
Negative-working, IR-sensitive dry printing plates utilize an oleophobic topmost layer, a nitrocellulose-based imaging layer ablatable by laser discharge, and a grained metal substrate with no heat-insulating layer intervening between the imaging layer and the substrate.