Non-aqueous Ink Surface Energy Control for Roller Transfer Staining

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Solution Overview

Problem

Non-aqueous inks used in inkjet printing systems face issues with roller transfer staining due to the coloring material being retained on the printing substrate, leading to image density reduction and contamination, while maintaining high image density is challenging without compromising ink absorption properties.

Innovation Solution

A non-aqueous ink with a total surface free energy of 25 to 30 mN/m and a dispersive component ratio of 0.55 to 0.75, paired with a printing substrate having a coating layer with inorganic particles and a total surface free energy of 30 to 50 mN/m and a dispersive component ratio of 0.80 to 1.0, which enhances ink absorption and prevents roller transfer staining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a non-aqueous ink is used to print on plain paper, then the printing substrate transport is facilitated (no curling or cockling), but the image density is reduced due to poor separation of solvent from coloring material

Engineering Contradiction:
Improveprinting substrate transportVSAvoidimage density
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling the surface free energy (25-30 mN/m) and dispersive component ratio (0.55-0.75) of the non-aqueous ink, and matching it with a printing substrate having specific surface properties (total surface free energy 30-50 mN/m, dispersive component ratio 0.80-1.0). This parameter optimization enables both easy substrate transport and high image density by achieving proper ink absorption and coloring material fixation.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the ash content of the printing substrate is increased to improve image density, then the coloring material is retained on the surface, but roller transfer staining occurs due to transferred coloring material

Engineering Contradiction:
Improveimage densityVSAvoidroller transfer staining
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by changing the surface energy parameters of both the ink and substrate. The non-aqueous ink is formulated with total surface free energy of 25-30 mN/m and dispersive component ratio of 0.55-0.75, while the printing substrate has total surface free energy of 30-50 mN/m and dispersive component ratio of 0.80-1.0. This parameter matching ensures proper wetting and absorption that fixes coloring material effectively, preventing roller transfer staining while maintaining high image density.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining specific components in the non-aqueous ink formulation (solvent, coloring material, and surface energy modifiers) and using a printing substrate with specific coating properties. This composite approach creates a system where the ink and substrate work together to achieve both high image density and prevent roller transfer staining through optimized surface interactions.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If the coloring material is retained on the surface of the printing substrate to increase image density, then the printed item has high image density, but the coloring material transfers to the roller and soils subsequent printed items

Engineering Contradiction:
Improveimage densityVSAvoidprinted item contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the surface free energy and dispersive component ratio of both the non-aqueous ink and printing substrate. The ink is formulated with total surface free energy of 25-30 mN/m and dispersive component ratio of 0.55-0.75, while the substrate has total surface free energy of 30-50 mN/m and dispersive component ratio of 0.80-1.0. This parameter optimization ensures that coloring material is retained on the substrate surface with proper adhesion strength, achieving high image density while preventing transfer to rollers and contamination of subsequent printed items.

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

The solution effectively suppresses roller transfer staining while maintaining high image density by optimizing the affinity and absorption properties between the ink and the substrate, ensuring rapid ink penetration and satisfactory fixing on the substrate.

Implementation Method 1

the coloring material and the solvent tend to be prone to penetrating together into gaps between the fibers of the printing substrate

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the non-aqueous ink has a total surface free energy, calculated from the Kaelble-Uy theoretical formula, of 25 to 30 mN/m, and a dispersive component ratio

Methodology Applied
Scientific EffectSurface free energy: Surface Tension

Implementation Method 3

the printing substrate has a coating layer comprising inorganic particles, has a total surface free energy, calculated from the Kaelble-Uy theoretical formula, of 30 to 50 mN/m, has a dispersive component ratio represented by the formula (1) of 0.80 to 1.0, and exhibits a liquid absorption property for the inorganic particles

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

the printing substrate has a coating layer comprising inorganic particles, has a total surface free energy, calculated from the Kaelble-Uy theoretical formula, of 30 to 50 mN/m

Methodology Applied
Scientific EffectSurface free energy: Surface Tension

Data Source

PatentUS8585197B2Method for printing non-aqueous ink and printing substrate for non-aqueous ink
Publication Date: 2013.11.19 RISO KAGAKU CORP

AI summary

A method for printing a non-aqueous ink onto a printing substrate, using a non-aqueous ink including a coloring material and a non-aqueous solvent is provided, wherein the non-aqueous ink has a total surface free energy, calculated from the Kaelble-Uy theoretical formula, of 25 to 30 mN/m, and a dispersive component ratio of 0.55 to 0.75, and the printing substrate has a coating layer containing inorganic particles, has a total surface free energy, calculated from the Kaelble-Uy theoretical formula, of 30 to 50 mN/m, has a dispersive component ratio of 0.80 to 1.0, and exhibits a liquid absorption property for the inorganic particles of 0.30 or greater. The method for printing a non-aqueous ink enables roller transfer staining to be suppressed while maintaining high image density.