Litho Ink Additives to Eliminate Feedback
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Solution Overview
Problem
Web-offset lithographic printing faces issues with ink feedback and excessive ink build-up on non-printing plates, which lead to defects in printed materials, particularly during high-speed operations and color changes, where existing solutions are either expensive, inconvenient, or require process interruptions.
Innovation Solution
Incorporating a water-soluble alkyl thioether surfactant or an alkoxylated modified rosin, such as ethoxylated rosin, into the lithographic ink compositions to reduce or eliminate ink feedback and build-up, these additives can be used in oil-based or radiation-curable inks, and are applied during the printing process to improve ink transfer and reduce residue on rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional lithographic ink compositions are used, then printing can proceed without interruption, but ink feedback and build-up occur on non-printing plates and rollers causing defects
Solution Approach 1:
The patent introduces a dampening agent as an intermediary substance that modifies the interaction between ink and the dampening roller surface. The dampening agent creates a barrier that prevents ink from adhering to the dampening roller, thereby eliminating the feedback loop while allowing continuous printing operations to proceed without interruption or quality defects
Solution Approach 2:
The patent changes the chemical parameters of the ink composition by incorporating specific additives including silicones, fluorocarbons, or charged particles. These parameter changes modify the surface energy and adhesion properties of the ink, preventing it from building up on non-printing areas and dampening rollers while maintaining print quality during continuous operation
2Adaptability or versatility
If printing presses perform multiple color changes in a single day, then versatility is improved, but ink feedback and scumming increase requiring thorough cleansing
Solution Approach 1:
The dampening agent acts as a mediator that prevents direct contact and adhesion between ink residues and the dampening roller surface during color changes. This intermediary layer allows the press to switch between colors without ink buildup, reducing the frequency and intensity of cleansing operations while maintaining versatility
Solution Approach 2:
The patent extracts and removes the problematic component (ink adhesion to dampening rollers) by introducing repellent substances. This extraction of the harmful interaction enables multiple color changes without accumulating tinting and scumming, allowing the system to maintain adaptability without generating harmful factors
3Reliability
If passive hydrophilic chrome rollers are used, then damping control is improved, but they are not perfect in preventing tinting and scumming
Solution Approach 1:
The patent creates a composite dampening system by combining the passive hydrophilic chrome roller base material with additional functional coatings or chemical additives. This composite approach maintains the reliable damping control of the chrome roller while adding ink-repellent properties that eliminate residual tinting and scumming issues
Solution Approach 2:
The patent modifies the surface parameters of the chrome roller through chemical treatment or coating with substances that change its surface energy characteristics. This parameter change enhances the hydrophilic properties and adds ink repellency, improving reliability while eliminating the harmful residual effects that the base material alone could not prevent
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 use of these additives significantly reduces ink feedback and build-up on rollers, maintaining print quality and efficiency, even during high-speed operations and frequent color changes, without the need for expensive equipment or process interruptions.
Implementation Method 1
Incorporating a water-soluble alkyl thioether surfactant or an alkoxylated modified rosin, such as ethoxylated rosin, into the lithographic ink compositions to reduce or eliminate ink feedback and build-up
Implementation Method 2
The fountain solution typically forms a film on the water receptive areas of the plate, but forms tiny droplets on the water repellent areas
Implementation Method 3
The printing (image) areas are typically hydrophobic and ink receptive, while the non-printing areas are typically hydrophilic and water receptive
Data Source
AI summary
Provided are web-offset lithographic ink compositions that contain an alkyl thioether surfactant, an alkoxylated modified rosin, or a combination thereof. The ink compositions can be oil-based inks or water-based inks that can be radiation-curable. The resulting ink compositions can be used in web-offset lithographic printing to substantially reduce or eliminate the ink feedback and ink build-up that occurs during printing. Also provided are methods for reducing or eliminating ink feedback and build-up during lithographic printing processes.