Ink Conductivity Control for Droplet Discharge Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The mixing of pigment and dye inks in liquid droplet discharge apparatuses often leads to pigment aggregation, causing nozzle clogging and reduced discharge stability due to dispersion destruction, which existing solutions fail to adequately address.

Innovation Solution

The use of a liquid droplet discharge apparatus with a specific conductivity relationship between pigment and dye inks, where the conductivity of the dye ink is between 2.0 to 5.0 mS/cm and the pigment ink is between 0.5 to 2.5 mS/cm, along with self-dispersing pigments and metallic salt structures, to maintain pigment dispersibility and prevent aggregation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pigment ink and dye ink are mixed on the nozzle surface, then both letter and image recording quality can be achieved, but pigment aggregation occurs causing nozzle clogging and reduced discharge stability

Engineering Contradiction:
Improverecording qualityVSAvoiddischarge stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent controls the conductivity of dye ink within 2.0 to 5.0 mS/cm and pigment ink within 0.5 to 2.5 mS/cm to prevent pigment aggregation when the inks mix on the nozzle surface, thereby maintaining discharge stability while enabling both letter and image recording capabilities

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses self-dispersing pigments with specific metallic salt structures that maintain dispersibility even when mixed with dye ink, creating a composite ink system that prevents aggregation and maintains reliable discharge performance

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If existing solutions add polymers or regulate counter ions to prevent pigment aggregation, then some dispersion stability is improved, but pigment aggregation still occurs on the nozzle surface causing discharge errors

Engineering Contradiction:
Improvedispersion stabilityVSAvoiddischarge stability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent specifically controls the conductivity parameter of the inks (dye ink: 2.0-5.0 mS/cm, pigment ink: 0.5-2.5 mS/cm) to prevent pigment aggregation, providing a more effective solution than previous polymer additions or counter ion regulation methods

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 configuration ensures excellent discharge stability and reduced pigment aggregation, even when pigment and dye inks are mixed, by controlling the conductivity and using self-dispersing pigments with metallic salt structures, thereby enhancing the ink's solubility and preventing nozzle clogging.

Implementation Method 1

The conductivity of the dye ink is between 2.0 to 5.0 mS/cm and the conductivity of the pigment ink is between 0.5 to 2.5 mS/cm

Methodology Applied
Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentEP2540507B1Liquid droplet discharge apparatus and ink set
Publication Date: 2016.02.24 SEIKO EPSON CORP
  • EP2540507B1 patent drawingFigure 1
  • EP2540507B1 patent drawingFigure 2
  • EP2540507B1 patent drawingFigure 3

AI summary

A liquid droplet discharge apparatus includes a head member. The head member is provided with a nozzle surface, a plurality of nozzle arrays including a first nozzle array and a second nozzle array is arranged on the nozzle surface, the nozzle array includes a plurality of nozzle holes which are arranged in a predetermined pattern, the first nozzle array discharges a pigment ink which contains water and a pigment, the second nozzle array discharges a dye ink which contains water and a dye, and the relationship between the conductivity [E1 (mS/cm)] of the pigment ink and the conductivity [E2 (mS/cm)] of the dye ink is expressed by the formula 0<(E2-E1)≤3.