Radiation-Curable White Ink for Digital Offset Printing
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Solution Overview
Problem
Conventional digital offset inks face challenges such as solubility issues with dampening fluids, swelling of imaging member surfaces, poor release properties, and limited curing performance, which affect image quality and efficiency in high-speed variable data printing processes.
Innovation Solution
Development of radiation-curable white digital offset inks with high pigment loading, optimized wetting and release properties, and compatibility with non-aqueous dampening fluids, enabling efficient transfer and partial curing for improved image quality and process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional digital offset inks are used, then solubility with dampening fluids is achieved, but swelling of imaging member surfaces occurs causing poor release properties
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink, specifically using radiation-curable acrylic or epoxy-based inks with controlled pigment loading (10-50% by weight) and viscosity (50-5000 cP at 25°C). These parameter changes allow the ink to be compatible with non-aqueous dampening fluids while preventing swelling of the imaging member surface, thereby resolving the contradiction between solubility and release properties.
Solution Approach 2:
The invention uses composite ink formulations combining radiation-curable resins (acrylic or epoxy), pigments, and specific additives that create a material with dual functionality: compatibility with dampening fluids and non-swelling properties on imaging members. This composite approach enables the ink to achieve both solubility requirements and release properties simultaneously.
2Manufacturing precision
If high pigment loading is used to improve image quality, then color strength increases, but viscosity increases making ink delivery difficult
Solution Approach 1:
The patent formulates the ink with dynamic rheological properties where viscosity can vary with shear rate and temperature. The ink exhibits shear-thinning behavior and controlled temperature dependence, allowing it to maintain stability during storage and delivery while enabling smooth flow during application. This dynamic property resolution allows high pigment loading (10-50% by weight) without compromising ink delivery.
Solution Approach 2:
The invention carefully controls the viscosity parameter within the range of 50-5000 cP at 25°C, and adjusts other parameters such as pigment particle size distribution and resin molecular weight to maintain optimal balance between image quality and ink deliverability through the printing system.
3Productivity
If radiation-curable ink is used for high-speed printing, then curing speed increases, but compatibility with system component materials becomes challenging
Solution Approach 1:
The patent selects radiation-curable chemistries (acrylic or epoxy-based) with appropriate molecular weights and functional group densities to achieve rapid curing while maintaining compatibility with imaging member materials such as photopolymer emulsion layers and silicone-based components. The ink formulation parameters are optimized to ensure no adverse reactions occur during the curing process, resolving the contradiction between curing speed and material compatibility.
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 new inks achieve high transfer efficiency, reduce ghosting, and maintain image quality by adhering correctly to imaging member surfaces while being compatible with non-aqueous dampening fluids, enhancing the capabilities of digital offset printing systems.
Implementation Method 1
radiation-curable ink composition... partial curing... efficient transfer
Data Source
AI summary
A white ink composition for ink-based digital printing includes a white pigment. The white pigment is titanium dioxide. A method for ink-based digital printing includes applying dampening fluid to an imaging member to form a dampening fluid layer, patterning the dampening fluid layer using a laser imaging system, applying a white ink composition to the imaging member surface having the patterned dampening fluid disposed thereon to form an ink image, partially curing the ink image, and transferring the partially cured ink image to a printable substrate.