Inkjet Ink Set with Pre-treatment Fixing Fluid for Offset Media

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Solution Overview

Problem

Current inkjet printing technologies face challenges in achieving high-speed printing on coated offset media due to issues with ink absorption, bleed control, and image quality, particularly with aqueous inks, which result in reduced optical density and gloss, and can lead to pen reliability problems.

Innovation Solution

An inkjet ink set comprising a pre-treatment fixing fluid with calcium-containing crashing agents, surfactants, and a polyurethane binder, combined with specific liquid inks, is used for wet-on-wet printing, dynamically lowering surface tension and improving interaction with the media to enhance print quality and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If aqueous inks are used for high-speed printing on coated offset media, then printing speed is improved, but image quality (optical density and gloss) deteriorates

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A pre-treatment fixing fluid is introduced as an intermediary substance applied to the coated offset media before the aqueous ink. This fluid modifies the media surface properties to enhance ink absorption and interaction, thereby maintaining high-speed printing capability while improving image quality attributes including optical density and gloss.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pre-treatment fixing fluid dynamically lowers the surface tension of the media surface, changing the physical-chemical parameters to optimize aqueous ink wetting and absorption. This parameter modification enables the ink to interact more effectively with the media at high printing speeds without compromising image quality.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If pre-treatment fixing fluid with high crashing agent content is used, then ink absorption and bleed control are improved, but pen reliability deteriorates

Engineering Contradiction:
Improveink absorption and bleed controlVSAvoidpen reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The pre-treatment fixing fluid formulation dynamically adjusts surface tension through the interaction of crashing agents (calcium propionate and calcium nitrate) with the media and ink. This dynamic parameter change allows effective ink control while maintaining pen reliability by preventing excessive precipitation that would cause nozzle issues.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pre-treatment fixing fluid is formulated as a composite system containing specific crashing agents (calcium propionate and calcium nitrate), surfactants, and water in optimized proportions. This composite formulation achieves both effective ink absorption control and pen reliability by balancing the properties of individual components.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If conventional ink formulations are used, then formulation simplicity is maintained, but print durability and mechability are insufficient

Engineering Contradiction:
Improveformulation simplicityVSAvoidprint durability
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The ink formulation is enhanced as a composite system incorporating a polyurethane binder alongside traditional ink components. This composite formulation improves print durability and mechability through the binding properties of polyurethane while maintaining relative formulation simplicity by integrating the binder into the existing ink structure rather than creating a completely separate system.

Inventive Principle:
Principle #40Composite materials

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 inkjet ink set provides improved print quality, reliability, and durability at high speeds, with enhanced optical density, gloss, and mechability, while maintaining nozzle health and decap performance, allowing for high-speed printing on coated offset media without compromising quality.

Implementation Method 1

dynamically lowering surface tension and improving interaction with the media

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

calcium-containing crashing agents consisting of calcium propionate and calcium nitrate

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

a polyurethane binder

Methodology Applied
Scientific EffectPolymer binding: Binder

Data Source

PatentEP3433326B1Inkjet ink set with a pre-treatment fixing fluid
Publication Date: 2022.08.31 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3433326B1 patent drawingFigure 1
  • EP3433326B1 patent drawingFigure 2

AI summary

An inkjet ink set comprising a pre-treatment fixing fluid including calcium-containing crashing agents; at least a co-solvent; one or more surfactants and a balance of water; and, at least, a liquid ink. The liquid ink includes a pigment dispersion, a surfactant, a polyurethane binder, a co-solvent and a balance of water. Also disclosed are and inkjet printing system containing such ink set and the method for printing in such inkjet printing system.