Water-Based Ink Suspension for Digital Printing
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Solution Overview
Problem
Digital ink-jet printing faces issues with VOC emissions, nozzle clogging, and counter-printing due to quick-drying inks, leading to material waste, equipment damage, and health hazards, particularly in large-format industrial printing on flexible materials.
Innovation Solution
A concentrated suspension with less than 3% VOC content, comprising pigments, dispersing agents, and aqueous solvents, optimized for ink-jet printing, which reduces VOC emissions and prevents nozzle clogging by maintaining ink fluidity and preventing drying within printheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If inks are formulated with quick-drying products (low boiling-point alcohols and/or glycols), then drying speed is improved, but nozzle clogging and VOC emissions increase
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by replacing quick-drying alcohols and glycols with water as the solvent. This parameter change maintains the drying functionality through water evaporation while eliminating the harmful effects of nozzle clogging and excessive VOC emissions associated with traditional quick-drying formulations.
Solution Approach 2:
The patent employs a water-based formulation that allows for easier and more frequent cleaning of the printhead nozzles. By using water as the solvent, the system can be quickly flushed and maintained, effectively treating the potential clogging issue as a manageable maintenance problem rather than a reliability failure.
2Productivity
If inks are formulated with quick-drying products, then printing speed is improved, but counter-printing and staining of transport cylinders occur
Solution Approach 1:
The patent modifies the ink formulation by using water as the solvent instead of quick-drying organic compounds. This parameter change allows the ink to dry at appropriate speeds without creating the excessive viscosity or rapid evaporation that causes counter-printing and staining of transport cylinders, thereby maintaining productivity while eliminating harmful effects.
3Duration of action of moving object
If inks are formulated with quick-drying products, then drying performance is improved, but VOC emissions increase causing health and environmental hazards
Solution Approach 1:
The patent fundamentally changes the solvent parameter from organic quick-drying compounds to water. This parameter change maintains effective drying performance through water evaporation while completely eliminating or significantly reducing VOC emissions, thereby resolving the contradiction between drying performance and environmental/health hazards.
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 solution significantly reduces VOC emissions, prevents nozzle clogging, and enhances printing quality and productivity by ensuring consistent ink flow and extended printhead life, while minimizing maintenance and environmental impact.
Implementation Method 1
The inks generally used in ink-jet printers consist of water, pigments and various solvents... the solvent is an aqueous solvent... the aqueous solvent is preferably water, more preferably distilled water
Implementation Method 2
said at least one pigment is present in a concentration comprised between 18 and 65% weight/weight (w/w), the dispersing agent is present in the suspension in a concentration comprised between 5 and 55% w/w
Data Source
AI summary
The present invention relates to a suspension comprising at least one pigment, a dispersing agent and a solvent. Preferably, the suspension has a volatile organic compound (VOC) content less than 3% w/w. Furthermore, the invention relates to an ink comprising the suspension and a printing process comprising at least one step of using the ink.