Electrostatic Toner Viscoelasticity Fixability Gloss

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Solution Overview

Problem

The existing electrostatic image developing toners face challenges in achieving suitable fixability and maintaining consistent glossiness between images fixed under high-temperature, high-pressure and low-temperature, low-pressure conditions, with variations in glossiness due to differences in toner particle deformation under varying fixing conditions.

Innovation Solution

The electrostatic image developing toner includes toner particles with a binder resin and resin particles, where the loss tangents at specific temperatures and strains are controlled within certain ranges, and the number average molecular weight of the tetrahydrofuran-soluble component is between 5000 and 15000, along with crosslinked styrene (meth)acrylic resin particles, to ensure uniform viscoelasticity and reduced deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If toner particles are designed to be easily melted by heat to achieve suitable fixability, then fixability is improved, but the difference in glossiness between images fixed under high-temperature high-pressure condition and low-temperature low-pressure condition increases

Engineering Contradiction:
ImprovefixabilityVSAvoidglossiness consistency
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent applies parameter changes by precisely controlling the viscoelastic properties of the binder resin through specific measurements of storage modulus and loss tangent at defined temperatures (90°C and 150°C) and frequencies (1 Hz and 10 Hz). By adjusting these physical parameters within specified ranges, the toner achieves both suitable fixability and consistent glossiness across different fixing conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining the binder resin with specific ratios of crystalline resin (4-50 mass%) and amorphous resin (50-96 mass%). This composite structure allows the toner to exhibit both the melting characteristics needed for fixability and the elastic properties needed for glossiness consistency, resolving the contradiction between these two requirements

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

This approach enables suitable fixability and reduces the difference in glossiness between images fixed under different conditions, ensuring consistent image quality by limiting toner particle deformation and maintaining close viscoelasticity at various temperatures and strains.

Implementation Method 1

the loss tangents at specific temperatures and strains are controlled within certain ranges... to ensure uniform viscoelasticity and reduced deformation

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP4411480A1Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, image-forming device and image-forming method
Publication Date: 2024.08.07 FUJIFILM BUSINESS INNOVATION CORP
  • EP4411480A1 patent drawingFigure 1
  • EP4411480A1 patent drawingFigure 2
  • EP4411480A1 patent drawing

AI summary

An electrostatic image developing toner including toner particles including a binder resin. When loss tangents tanδ at a temperature of 90°C and a strain of 1%, a temperature of 90°C and a strain of 50%, a temperature of 150°C and a strain of 1%, and a temperature of 150°C and a strain of 50%, the loss tangents tanδ being determined by measurement of dynamic viscoelasticity of the electrostatic image developing toner, are defined as D1(90), D50(90), D1(150), and D50(150), respectively, D1(90), D50(90), D1(150), and D50(150) are each 0.5 or more and 2.5 or less, D50(150) - D1(150) is less than 1.5, and D50(90) - D1(90) is less than 1.0; the toner particles further include resin particles; and the number average molecular weight of a component of the toner particles, the component being soluble in tetrahydrofuran, is 5000 or more and 15000 or less.