Dual Carbon Black Aqueous Ink for Stable High-Density Ejection
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Solution Overview
Problem
Ink jet recording methods face issues with ejection failure, density unevenness, and blurring when recording high optical density images due to air bubbles in the ink flow path, particularly during continuous large ink consumption.
Innovation Solution
An aqueous ink formulation using two types of self-dispersible carbon black pigments with specific particle diameter ratios and anionic groups, along with a nonionic surfactant, to stabilize and break air bubbles, ensuring stable ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If self-dispersible carbon black is used to achieve high optical density, then image quality improves, but air bubbles mix in the ink flow path causing ejection failure
Solution Approach 1:
The patent changes the particle size parameters of carbon black by using a dual-pigment system with specific D50 values (first pigment: 80-150nm, second pigment: 30-60nm). This parameter optimization reduces air bubble formation while maintaining high optical density, resolving the contradiction between image quality and ejection stability
Solution Approach 2:
The patent creates a composite pigment system combining two different carbon black pigments with distinct particle size distributions. This composite approach achieves both high optical density (from the finer second pigment) and reduced air bubble mixing (from the coarser first pigment), simultaneously improving image quality and ejection reliability
2Quantity of substance
If large ink consumption amount is used for solid images, then image coverage improves, but air bubbles accumulate in the flow path causing non-ejection
Solution Approach 1:
The patent optimizes the particle size parameters of the carbon black pigments, specifically using a D50 ratio of 1.3 or more between the first and second pigments. This parameter configuration reduces air bubble accumulation during high ink consumption, enabling stable ejection even for solid image recording
Solution Approach 2:
The patent converts the potential harm of high ink consumption (which causes air bubble accumulation) into a benefit by using the dual-pigment system. The specific particle size distribution transforms the high-volume ink flow from a problem into an opportunity to demonstrate the system's superior bubble-resistance and continuous ejection capability
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 reduces air bubble stability, maintaining ejection accuracy and improving optical density even during continuous high ink consumption, preventing non-ejection and image defects.
Implementation Method 1
the ink includes a surfactant
Implementation Method 2
the first pigment and the second pigment are each self-dispersible carbon black in which an organic group including an anionic group is bonded to a surface of a particle of carbon black
Data Source
AI summary
Provided is an aqueous ink for ink jet capable of recording an image having a high optical density, in which the non-ejection of the ink is less liable to occur, even when an image having a large ink consumption amount is continuously recorded. The aqueous ink for ink jet includes: a first pigment; a second pigment; and a surfactant. The first pigment and the second pigment are each self-dispersible carbon black in which an organic group including an anionic group is bonded to a surface of a particle of carbon black. A ratio of a cumulative 50% particle diameter (nm) of the first pigment on a volume basis to a cumulative 50% particle diameter (nm) of the second pigment on a volume basis is 1.3 times or more, and the cumulative 50% particle diameter of the second pigment on a volume basis is 60 nm or less.