Inkjet Image Formation Using High SP Value Solvent Removal

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Solution Overview

Problem

Inkjet recording methods face challenges in achieving sufficient dispersion stability and rub resistance in images formed, despite improvements in rub resistance through the use of volatile solvents and acid-functionalized polymer particulates.

Innovation Solution

An image forming method employing an ink composition with a water-soluble solvent having an SP value of 27.5 or more, a pigment, and polymer particles, where at least a part of the volatile solvent is removed from the ink composition on a recording medium, enhancing dispersion stability and rub resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If volatile solvent and acid-functionalized polymer particulates are used to improve rub resistance, then the image shows better resistance to rubbing, but the dispersion stability of the ink is insufficient

Engineering Contradiction:

Improverub resistanceVSAvoiddispersion stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by incorporating a specific water-soluble organic solvent (SP value 27.5 or more, 30-80 mass%) alongside acid-functionalized polymer particulates. This parameter modification resolves the contradiction by achieving both improved dispersion stability and rub resistance simultaneously, rather than sacrificing one for the other.

Inventive Principle:

Principle #35Parameter changes

2Strength

If heating is applied to remove volatile solvent to improve rub resistance, then the image shows better rub resistance, but the process complexity and energy consumption increase

Engineering Contradiction:

Improverub resistanceVSAvoidheating energy

Core Design Contradiction:

StrengthVSUse of energy by stationary object

Solution Approach 1:

The patent converts the harmful effect of volatile solvent (which causes poor rub resistance when remaining in the ink) into a beneficial outcome by selecting solvents with specific SP values that facilitate controlled removal. The volatile solvent's tendency to evaporate is harnessed to achieve image fixation and rub resistance without requiring excessive heating energy, as the solvent removal occurs more efficiently at lower temperatures due to the specific solvent characteristics.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 method improves the stability and rub resistance of images formed, while maintaining high-speed recordability and preventing curling, by using a specific formulation of ink composition and solvent removal process.

Implementation Method 1

removing at least a part of the volatile solvent from the ink composition on the recording medium

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS8187675B2Image forming method

Publication Date: 2012.05.29 FUJIFILM CORP

AI summary

The invention provides an image forming method including at least: applying, onto a recording medium, an ink composition containing at least a water-soluble solvent, a pigment, a polymer particle and water; and removing at least a part of the volatile solvent from the ink composition on the recording medium. Herein, the water-soluble solvent contains at least a volatile water-soluble solvent having an SP value of 27.5 or more at an amount of 30 mass % thereof.