Acrylate Ink Formulation for Digital Offset Lithography
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Solution Overview
Problem
Digital offset lithography printing systems face challenges with ink delivery, solubility in dampening fluids, ghosting issues, high manufacturing costs, and inefficient image transfer, particularly with anilox roller-type systems and non-aqueous dampening fluids.
Innovation Solution
Development of acrylate ink compositions with specific formulations, including pigments, acrylates, dispersants, photoinitiators, stabilizers, and rheology modifiers, optimized for stable rheology and compatibility with reimageable surfaces and non-aqueous dampening fluids, enabling efficient delivery and transfer in digital offset printing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If related art offset-type inks are used in digital offset lithography printing systems, then printing can be performed with existing systems, but the inks exhibit poor delivery via anilox roller-type inking systems, solubility in dampening fluids causing ghosting, and inefficient image transfer
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink, specifically using a pigment dispersion system with controlled particle size distribution (D50 between 0.5-2.0 micrometers) and specific binder resin ratios, to achieve optimal rheological properties that enable reliable delivery through anilox rollers while preventing solubility issues in dampening fluids
Solution Approach 2:
The ink formulation employs a composite material system combining specifically selected pigment particles, binder resins, and dispersants in controlled ratios, creating a stable dispersion that resists solubility in dampening fluids while maintaining deliverability through printing system components
2Ease of operation
If inks are made soluble in dampening fluids for easy application, then ink application becomes simpler, but ghosting and image background issues occur
Solution Approach 1:
The patent converts the potential harm of ink-dampening fluid interaction by formulating an ink that is specifically insoluble in the dampening fluid, using this insolubility property to prevent ghosting and background issues while still allowing proper ink application through the printing system
3Productivity
If ink formulations are optimized for high transfer efficiency, then image transfer improves, but compatibility with printing system components and dampening fluids deteriorates
Solution Approach 1:
The patent applies local quality by creating specific functional zones within the ink formulation: pigment particles optimized for transfer efficiency, binder resins optimized for component compatibility, and dispersants that ensure stable suspension, with each component performing its specific function optimally
4Adaptability or versatility
If conventional inks are used to maintain compatibility with existing printing systems, then system compatibility is maintained, but manufacturing costs and operational costs increase
Solution Approach 1:
The patent reduces manufacturing cost by optimizing pigment concentration parameters and using readily available binder resin materials in specific ratios, achieving compatible performance with conventional printing systems while lowering material costs compared to conventional ink formulations
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 acrylate ink compositions improve ease of delivery, transfer efficiency, and print quality on various substrates, maintaining compatibility with printing system components and reducing ghosting, while being cost-effective and compatible with diverse dampening fluids.
Implementation Method 1
The ink may be transferred directly to a target substrate, such as paper, or may be applied to an intermediate surface, such as an offset (or blanket) cylinder in an offset printing system
Implementation Method 2
The disclosed acrylate ink compositions exhibit stable rheology that enables delivery using an anilox roll delivery system, and demonstrate desirable transferability to a reimageable surface of an imaging member
Implementation Method 3
Regions of the dampening fluid are removed by exposure to a focused radiation source (e.g., a laser light source) to form pockets
Implementation Method 4
The inked surface is then brought into contact with a substrate, and the ink transfers from the pockets in the dampening fluid layer to the substrate
Data Source
AI summary
Compatible acrylate ink sets include acrylate ink composition having 30% or less by weight pigment, 10% or less dispersant, between 40% and 80% acrylate, 12% or less photoinitiator, a viscosity between 5×105 and 3×107 cps at 35° C., and a 60 second tack between 25 and 50 g-m at 35° C.