Ink-Jet Recording Ink Particle Size Control
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Solution Overview
Problem
Conventional ink-jet recording inks using colored particles suffer from blurring and stability issues due to particle size distribution and density differences, leading to clogged nozzles and image distortion.
Innovation Solution
An ink-jet recording ink with colored particles having a volume average diameter of 1 μm to 5 μm and a controlled particle diameter distribution, where particles larger than 1.5 times the average diameter are 5 vol% or less, ensuring improved ejection and storage stability by preventing sedimentation and floating, and maintaining sharp image edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If colored particles with broad diameter distribution are used, then the ink can be manufactured easily, but large particles cause nozzle clogging and storage instability
Solution Approach 1:
The patent applies parameter changes by strictly controlling the particle diameter within 0.01 μm to 20 μm range and limiting particles ≥1/5 of nozzle diameter to 5 vol% or less. This parameter optimization resolves the contradiction by enabling easy manufacturing with commercially available particles while preventing nozzle clogging and storage instability through controlled particle size distribution.
2Device complexity
If particle diameter is increased, then the ink formulation becomes simpler, but sedimentation velocity increases reducing storage stability
Solution Approach 1:
The patent optimizes particle diameter parameters to 0.01 μm to 20 μm, balancing formulation simplicity with storage stability. By controlling particles to be less than 1/5 of nozzle diameter and limiting larger particles to 5 vol% or less, the formulation remains simple while sedimentation velocity is controlled within acceptable ranges, preventing particle separation during storage.
3Productivity
If density of ink solvent differs from colored particles, then the ink can be prepared quickly, but particle separation occurs during storage
Solution Approach 1:
The patent controls particle density to be 1.0 to 1.5 g/cm³ and adjusts ink solvent composition to match this density range. By controlling the density difference to within 0.05 g/cm³, the patent achieves quick ink preparation without requiring extensive density adjustment, while preventing particle sedimentation or floating during storage through matched density parameters.
4Manufacturing precision
If small particles are used, then blurring is reduced, but ejection stability deteriorates due to meniscus distortion
Solution Approach 1:
The patent optimizes particle diameter to 0.01 μm to 20 μm, with specific control that particles ≥1/5 of nozzle diameter constitute 5 vol% or less of total particles. This parameter optimization resolves the contradiction by ensuring particles are small enough to prevent blurring while limiting the proportion of larger particles that could distort the meniscus and affect 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 achieves stable ejection and storage, preventing blurring and print dropouts, with sharp image edges and reduced bleeding, while minimizing the need for density adjusting agents and maintaining cost-effectiveness.
Implementation Method 1
the specific gravity of the ink solvent be the same as that of the colored particles in order to prevent the colored particles from separating out from the ink solvent
Implementation Method 2
a problem arises in that blurring can be observed with the naked eye and the edges of the image lines may be disturbed
Data Source
AI summary
An ink for ink-jet recording, by use of which the ejection stability and the storage stability are improved while the occurrence of blurring is prevented, includes water, a water soluble organic solvent and a colored particle as a coloring agent. The volume average diameter of the colored particles is about 1 μm to about 5 μm, and the amount of particles having diameters equal to or greater than about 1.5 times the volume average diameter is about 5 vol % or less with respect to the total volume of the colored particles.