Inkjet Ink Ohnesorge Number Control for Satellite Suppression

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Solution Overview

Problem

Inkjet recording apparatuses face challenges in suppressing satellite phenomenon and blurring when using aqueous ink on poorly absorbent recording media, leading to displaced ejection and widened line images.

Innovation Solution

The development of inkjet ink containing a pigment, a water-soluble organic solvent with both glycol ether and glycol compounds, and a surfactant, which maintains an Ohnesorge number between 0.180 and 0.188, optimizing viscosity and dynamic surface tension to prevent excessive spreading and enhance image formation on poorly absorbent media.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aqueous ink is used on poorly absorbent recording media, then image formation is possible, but satellite phenomenon occurs and line width increases due to excessive spreading

Engineering Contradiction:

Improveimage formation qualityVSAvoidline width control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the ink by adjusting the Ohnesorge number to a specific range (0.180-0.188) and controlling the dynamic surface tension to 53.0-58.0 mN/m. This parameter optimization balances the ink's spreading behavior on poorly absorbent media, preventing excessive spreading that causes satellite phenomenon while maintaining proper image formation and line width control.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite ink formulation containing multiple components: pigment, water-soluble organic solvent (combining glycol ether and glycol compound), water, and surfactant. This composite composition works synergistically to control the ink's rheological properties and surface tension, enabling precise control over spreading behavior on poorly absorbent recording media.

Inventive Principle:

Principle #40Composite materials

2Productivity

If ejection speed is increased, then productivity improves, but satellite phenomenon worsens due to displacement of ink landing position

Engineering Contradiction:

Improveejection speedVSAvoidink landing position accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the Ohnesorge number parameter to a narrow range (0.180-0.188), which specifically addresses the balance between ejection speed and landing position accuracy. This parameter control ensures that even at high ejection speeds, the ink maintains proper coherence and lands at the correct position, minimizing satellite phenomenon while preserving productivity.

Inventive Principle:

Principle #35Parameter changes

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

This formulation effectively suppresses displaced ejection and achieves the desired line width on poorly absorbent media by balancing viscosity and surface tension, ensuring proper image formation and moisture retention.

Implementation Method 1

σ represents the dynamic surface tension of the inkjet ink with a surface age of 0.027 milliseconds

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Implementation Method 2

μ represents the viscosity of the inkjet ink

Methodology Applied

Scientific EffectViscosity:

Data Source

PatentUS20240141187A1Inkjet ink and inkjet recording apparatus

Publication Date: 2024.05.02 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

Inkjet ink contains a pigment, a water-soluble organic solvent, water, and a surfactant. The water-soluble organic solvent contains both a glycol ether and a glycol compound. The inkjet ink has an Ohnesorge number Oh of 0.180 or more but 0.188 or less.