Liquid Electrophotographic Ink Composition with Tackifier

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Solution Overview

Problem

Liquid electrophotographic printing faces challenges with adhesion and transferability due to the low affinity of high molecular weight resins to substrates, leading to reduced durability of ink compositions.

Innovation Solution

A liquid electrophotographic ink composition comprising a charge director, a non-polar polymer carrier fluid, and ink particles with a polymeric resin and pigment, along with a tackifier to enhance adhesion and transferability by dissolving the tackifier in the carrier fluid and combining it with the charge director and ink particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high molecular weight resins are used to improve durability, then strength is improved, but adhesion deteriorates due to low affinity to substrates

Engineering Contradiction:
ImprovedurabilityVSAvoidadhesion
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent combines high molecular weight resins with low molecular weight resins to create a composite ink composition. The high molecular weight resin provides durability and strength, while the low molecular weight resin provides adhesion to substrates. This composite approach resolves the contradiction by integrating materials with complementary properties, allowing both durability and adhesion to be achieved simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different resin components to different functional requirements within the ink composition. The low molecular weight resin specifically targets the substrate interface to provide adhesion, while the high molecular weight resin forms the bulk structure for durability. This local differentiation of material properties allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

2Strength

If high molecular weight resins are used to improve durability, then strength is improved, but transferability deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidtransferability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The ink composition uses a composite of high and low molecular weight resins where the low molecular weight resin facilitates transferability during the printing process, while the high molecular weight resin ensures durability after transfer. The low molecular weight resin's lower viscosity and higher mobility enable easier transfer to substrates, while the high molecular weight resin provides the structural integrity for long-lasting images.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent exploits the dynamic behavior of resins at different stages of the printing process. During transfer, the low molecular weight resin provides fluidity and ease of movement. After transfer and drying, the high molecular weight resin provides structural stability. This dynamic adaptation of material properties throughout the process resolves the contradiction between transferability and durability.

Inventive Principle:
Principle #15Dynamics

3Force

If organic waxes are added to improve adhesion, then adhesion is improved, but device complexity increases due to additional components

Engineering Contradiction:
ImproveadhesionVSAvoidcomposition complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

Instead of adding organic waxes, the patent changes the molecular weight parameter of the resin components. By using low molecular weight resins (with molecular weights of 100-10,000 g/mol) instead of high molecular weight resins alone, the patent achieves improved adhesion through a fundamental parameter change rather than adding separate adhesive components. This approach improves adhesion while maintaining relatively simple composition.

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 inclusion of a tackifier improves the adhesion of the ink composition to substrates and facilitates better transfer from a blanket to the substrate, overcoming the adhesion-transferability trade-off and ensuring durable ink films.

Implementation Method 1

dissolving the tackifier in the carrier fluid

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

a charge director; a non-polar polymer carrier fluid

Methodology Applied
Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 3

facilitates better transfer from a blanket to the substrate, overcoming the adhesion-transferability trade-off and ensuring durable ink films

Methodology Applied
Scientific EffectThermal transfer: Conduction (thermal)

Data Source

PatentEP3265519B1Ink composition
Publication Date: 2020.04.08 HP INDIGO BV
  • EP3265519B1 patent drawingFigure 1
  • EP3265519B1 patent drawingFigure 2A~2D
  • EP3265519B1 patent drawingFigure 3A~3D

AI summary

Provided in one example hereinis aliquid electrophotographic ink composition. The composition includesa charge director, a non-polar carrier fluid comprising a polymer; andink particles each includinga polymeric resin and a pigment dispersed in the resin. The ink composition also includes a tackifier.