White Ink Formulation for Single-Pass Printing Stability
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Solution Overview
Problem
Ink-jet printing systems using titanium oxide-based white inks face challenges with sedimentation, leading to ejection failures and instability, particularly in single-pass systems, where high-speed printing is desired but current solutions fail to provide sufficient long-term stability and hiding properties.
Innovation Solution
A white ink formulation with 15-30% titanium oxide by weight, a weight average particle diameter of 180-250 nm, and a basic pigment dispersant, surface-treated with silica, combined with specific polymerizable compounds and a polymerization initiator, to enhance dispersion stability and hiding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If titanium oxide is used as the white pigment in white ink, then the hiding property is improved, but the pigment sedimentation occurs due to high specific gravity
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of titanium oxide within 180-250 nm and adjusting its content to 15-30% by weight. This optimization balances the high specific gravity of titanium oxide with adequate dispersion stability, preventing sedimentation while maintaining sufficient hiding property for effective printing.
Solution Approach 2:
The patent employs composite materials by combining titanium oxide pigment with specific polymerizable compounds and a polymerization initiator to form an active energy ray-curable ink system. This composite formulation enhances both the stability and performance of the white ink, allowing it to resist sedimentation while achieving good hiding properties.
2Stability of the object's composition
If hollow particles are used instead of titanium oxide to reduce sedimentation, then the printing stability is improved, but the hiding property deteriorates
Solution Approach 1:
The patent resolves this contradiction by changing the particle size parameter of titanium oxide to a specific range (180-250 nm), which is small enough to reduce sedimentation but sufficient to maintain hiding property. This parameter optimization allows the use of titanium oxide without requiring hollow particles, thereby maintaining both stability and hiding performance.
3Illumination intensity
If multiple ink-jet heads are used to improve printing concentration, then the hiding property is improved, but the apparatus size increases
Solution Approach 1:
The patent changes the concentration parameter of titanium oxide to an optimized range of 15-30% by weight, which achieves sufficient hiding property in a single pass. This eliminates the need for multiple ink-jet heads, thereby maintaining a compact apparatus size while achieving the desired printing concentration and hiding performance.
4Productivity
If the ink-jet head is fixed for high-speed printing, then the productivity is improved, but the pigment sedimentation in nozzles occurs
Solution Approach 1:
The patent applies parameter changes by optimizing the titanium oxide particle size to 180-250 nm and controlling its content at 15-30% by weight. These parameter optimizations ensure adequate flowability and prevent sedimentation in fixed ink-jet heads, enabling high-speed single-pass printing while maintaining ejection stability over extended periods.
Solution Approach 2:
The patent uses composite materials by formulating the white ink with titanium oxide, polymerizable compounds, and a polymerization initiator. This composite system provides both the high-speed printing capability and the sedimentation resistance required for stable operation of fixed ink-jet heads in single-pass systems.
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 formulation achieves high printing stability and good hiding properties, preventing nozzle voids and maintaining performance over extended periods in single-pass ink-jet printing systems.
Implementation Method 1
the ink is landed on a base material to be printed, and then active energy rays are applied to the ink to cause polymerization reaction of the ink components
Implementation Method 2
the content of the pigment dispersant is from 3 to 8 parts by weight with reference to 100 parts by weight of titanium oxide
Data Source
AI summary
To provide an ink-jet white ink of active energy ray-curable type, wherein the white ink has high printing stability and good hiding property, and is particularly suitable for printing on the single-pass ink-jet printing system. An ink-jet white ink of active energy ray-curable type, comprising titanium oxide, a pigment dispersant, and a polymerizable compound, wherein the content of the titanium oxide is from 15 to 30% by weight with reference to the total weight of the ink, and wherein the weight average particle diameter of the titanium oxide is 180 to 250 nm. The titanium oxide is titanium oxide whose surface is treated with silica and the pigment dispersant comprises a basic dispersant.