Electrostatic Toner with Phase-Separated Resins

Solution Overview

Problem

Electrophotographic toners with amorphous and crystalline resins face issues with streaky image defects in high temperature and high humidity environments due to compatibility between the resins, leading to deformation and poor image quality.

Innovation Solution

The development of an electrostatic charge image developing toner with toner particles containing an amorphous resin and a crystalline resin, where the phase-separated amount of crystalline resin is optimized to prevent excessive compatibility, maintaining a specific area ratio before and after heating, thereby reducing deformation and enhancing image stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If toner particles include both amorphous resin and crystalline resin, then low-temperature fixing properties are improved, but streaky image defects occur in high temperature and high humidity environments due to resin compatibility

Engineering Contradiction:

Improvefixing temperatureVSAvoidimage quality stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention creates a sea-island structure where crystalline resin forms discrete islands within an amorphous resin sea. This local phase separation ensures that the crystalline resin provides low-temperature fixing capability at specific locations while the amorphous resin maintains overall structural integrity and prevents streaky defects in high humidity environments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses a composite resin system combining amorphous and crystalline resins with controlled phase separation. The specific composition ratio and phase distribution create a material that exhibits both low-temperature fixing properties and resistance to streaky image defects through the synergistic interaction of the two resin phases.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If crystalline resin and amorphous resin are compatible, then toner particle homogeneity is improved, but toner particles deform under mechanical loads in high temperature and high humidity environments

Engineering Contradiction:

Improveresin compatibilityVSAvoidmechanical load resistance

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The invention creates a sea-island structure where crystalline resin forms discrete islands within an amorphous resin sea. This local phase separation ensures that the crystalline resin provides low-temperature fixing capability at specific locations while the amorphous resin maintains overall structural integrity and prevents streaky defects in high humidity environments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention controls the degree of phase separation between crystalline and amorphous resins by adjusting processing parameters such as cooling rate and annealing conditions. This parameter control optimizes the balance between resin compatibility (for homogeneity) and phase separation (for mechanical strength), preventing both excessive compatibility and complete separation.

Inventive Principle:

Principle #35Parameter changes

3Strength

If excessive phase separation occurs between crystalline resin and amorphous resin, then mechanical load resistance is improved, but toner particle structure becomes unstable

Engineering Contradiction:

Improvemechanical load resistanceVSAvoidphase-separated structure stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The invention controls the degree of phase separation between crystalline and amorphous resins by adjusting processing parameters such as cooling rate and annealing conditions. This parameter control optimizes the balance between resin compatibility (for homogeneity) and phase separation (for mechanical strength), preventing both excessive compatibility and complete separation.

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 optimized toner particles exhibit improved resistance to mechanical loads in high temperature and high humidity environments, preventing streaky image defects by maintaining a controlled phase-separated structure and area ratio of crystalline resin, ensuring better image quality and durability.

Implementation Method 1

toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement to determine an area ratio of the crystalline resin present on a surface of the toner particle before and after being heated

Methodology Applied

Scientific EffectPhase separation: Phase Change

Data Source

PatentUS9989871B2Electrostatic charge image developing toner, electrostatic charge image developer, and toner cartridge

Publication Date: 2018.06.05 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement to determine an area ratio of the crystalline resin present on a surface of the toner particle before and after being heated at a temperature of 50° C. and a humidity of 50% RH for a week, a relationship between an area ratio a (%) of the crystalline resin present on a surface of the toner particles before being heated and an area ratio b (%) of the crystalline resin present on a surface of the toner particles after being heated satisfies Expression (1): 0.05≤(b−a)/b≤0.50.