White Ink Opacity and Durability via Latex Optical Spacing
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Solution Overview
Problem
Ink-jet printing technologies face challenges in achieving desirable ink opacity and durability, particularly with certain pigments like metal oxides, which can result in suboptimal print quality and longevity.
Innovation Solution
A white ink formulation comprising an aqueous vehicle, metal oxide particles with high refractive index, and fusible latex particles that provide optical spacing, enhancing opacity and durability by adjusting the metal oxide to latex particle ratio and using heat fusion to create a more opaque and durable printed layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metal oxide particles are densely packed to increase opacity, then light scattering capability improves, but particle crowding reduces opacity and light scattering efficiency
Solution Approach 1:
The patent introduces a binder material as an intermediary substance between metal oxide particles. This binder creates optimal spacing that prevents particle crowding while maintaining high opacity, allowing light to scatter efficiently through the ink layer without the particles being too densely packed
Solution Approach 2:
The patent creates a composite ink formulation combining metal oxide particles with a binder material. This composite structure allows the metal oxide particles to maintain high opacity while the binder prevents excessive packing, achieving both high light scattering capability and maintained opacity
2Illumination intensity
If metal oxide particle concentration is increased to enhance opacity, then ink opacity improves, but ink durability deteriorates
Solution Approach 1:
The patent formulates a composite ink containing both metal oxide particles and binder material. The binder provides durability and adhesion properties that compensate for the potential weakness of high metal oxide concentration, while the metal oxide particles provide the necessary opacity
Solution Approach 2:
The patent optimizes the concentration parameters of both metal oxide particles and binder material to achieve a balance where sufficient opacity is maintained while durability is enhanced through the binder's protective and adhesive properties
3Illumination intensity
If metal oxide particle density is increased to improve opacity, then light scattering improves, but inkjet printability deteriorates
Solution Approach 1:
The binder acts as an intermediary that disperses metal oxide particles uniformly throughout the ink vehicle. This uniform distribution prevents particle aggregation and maintains smooth ink flow properties, enabling good inkjet printability while preserving high opacity
Solution Approach 2:
The patent adjusts the particle size and concentration parameters of metal oxide particles along with binder content to optimize both opacity and inkjet printability, ensuring the ink maintains appropriate viscosity and flow characteristics for inkjet deposition
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 increases print opacity by up to 25% and enhances durability, overcoming the limitations of densely packed metal oxide particles by using latex particles to create a more efficient light scattering effect and binding the metal oxide particles into a continuous, durable coating.
Implementation Method 1
by selecting metal oxide particles with a high refractive index (e.g., from 1.8 to 2.8), and latex particles with a relatively lower refractive index (e.g., from 1.3 to 1.6), the opacity of the ink when printed on a media sheet can further be unexpectedly increased
Implementation Method 2
In providing some optical spacing between metal oxide particles by interposing latex particles there between, opacity can be increased compared to inks without the latex particles present
Implementation Method 3
using heat fusion to create a more opaque and durable printed layer
Data Source
AI summary
The present disclosure provides a white ink comprising an aqueous ink vehicle, a white colorant, and latex particles. The colorant can consist essentially of metal oxide particles present at from 2 wt % to 50 wt %, can have an average particle size from 100 nm to 1000 nm, and can have a high refractive index from 1.8 to 2.8. The latex can be present in the ink at from 2 wt % to 20 wt %, can have a glass transition temperature from 0° C. to 130° C., and can have a low refractive index from 1.3 to 1.6. The metal oxide particles and latex particles can be present in the white ink at weight ratio is from 6:1 to 1:3.