Ink Set with Zwitterionic Surfactant for Film Wear Reduction
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Solution Overview
Problem
Inkjet recording apparatuses face challenges with inkjet inks containing self-dispersing pigments, which promote wear of the water-repellent film and lead to void defects and decreased image density, especially on uncoated surfaces, while water-based inks with pigment dispersion result in poor image quality due to pigment penetration.
Innovation Solution
An ink set comprising a water-based ink with high-structure carbon black, a dispersing resin, a zwitterionic surfactant, and a sugar alcohol, along with a cleaning solution containing a zwitterionic surfactant and sugar alcohol, is used to enhance ink ejection stability, prevent void defects, and inhibit water-repellent film wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-based ink containing self-dispersing pigment is used, then ease of manufacture is improved, but water-repellent film wear increases and image quality deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by specifying precise ratios of dispersing resin to pigment (1:10 to 1:30 by mass), pigment particle size distribution (D50: 0.03-0.1 μm, D90: 0.06-0.2 μm), and oil absorption number (100-200 mL/100g). These parameter optimizations resolve the contradiction by enabling effective pigment dispersion that protects the water-repellent film while maintaining manufacturing simplicity.
Solution Approach 2:
The patent employs composite material strategies by combining multiple pigment types (carbon black with specific properties), dispersing resins, and surfactants in optimized ratios. This composite approach creates an ink formulation that achieves both ease of manufacture and reduced water-repellent film wear through synergistic material interactions.
2Ease of manufacture
If water-based ink containing pigment dispersion is used, then ease of manufacture is improved, but image density decreases and void defects increase
Solution Approach 1:
The patent optimizes critical parameters including pigment oil absorption number (100-200 mL/100g), dispersing resin to pigment mass ratio (1:10 to 1:30), and pigment particle size distribution (D50: 0.03-0.1 μm, D90: 0.06-0.2 μm). These parameter changes ensure pigment remains sufficiently dispersed for easy manufacture while controlling penetration behavior to achieve high image density and eliminate void defects.
3Reliability
If cleaning operation is performed on ink ejection surface, then ink ejection stability is improved, but water-repellent film wears
Solution Approach 1:
The patent introduces surfactants as intermediary substances in the ink formulation that act as mediators between the pigment particles and the water-repellent film. These surfactants reduce surface tension and prevent direct abrasive contact between pigment particles and the film during cleaning operations, thereby maintaining film durability while ensuring ink ejection stability.
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 ink set achieves high image density, improved preservation and ejection stability, and reduces void defects and water-repellent film wear, ensuring reliable inkjet printing.
Implementation Method 1
a first zwitterionic surfactant having an amidoalkylbetaine structure
Implementation Method 2
The carbon black has an oil absorption number of at least 130 mL/100 g and no greater than 165 mL/100 g
Implementation Method 3
a dispersing resin
Implementation Method 4
The water-repellent film has a function of inhibiting occurrence of a phenomenon in which accuracy of ink placement decreases due to spreading wetting of ink over the ink ejection surface
Data Source
AI summary
An ink set includes an inkjet ink and a cleaning solution. The inkjet ink contains a first aqueous medium, a carbon black, a dispersing resin, a first zwitterionic surfactant having an amidoalkylbetaine structure, and a first sugar alcohol. The carbon black has an oil absorption number of at least 130 mL/100 g and no greater than 165 mL/100 g. A ratio of a content of the dispersing resin to a content of the carbon black is at least 12.0% by mass and no greater than 19.0% by mass. The cleaning solution contains a second aqueous medium, a second zwitterionic surfactant having an amidoalkylbetaine structure, and a second sugar alcohol.