Electrostatic Toner with Crystal Nucleating Agent

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Solution Overview

Problem

Electrophotographic toners with crystalline and amorphous resins face challenges in achieving low-temperature fixability while maintaining high image density and heat-resistant storage stability, as the compatibility between the two resins can reduce heat-resistant storage stability and dispersibility of the crystalline resin.

Innovation Solution

Incorporating o-acetoacetaniside as a crystal nucleating agent in toner base particles, with a content of 0.1 ppm by mass or more and 200 ppm by mass or less, to promote crystallization of the crystalline resin and improve dispersibility, thereby enhancing low-temperature fixability and image density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a crystalline resin is included to lower the toner fixing temperature, then low-temperature fixability is improved, but heat-resistant storage stability is reduced due to compatibility between the crystalline resin and amorphous resin

Engineering Contradiction:
Improvefixing temperatureVSAvoidheat-resistant storage stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

A crystal nucleating agent is introduced as an intermediary substance to promote crystallization of the crystalline resin. This intermediary facilitates the formation of a stable crystalline structure that prevents compatibility issues between the crystalline and amorphous resins, thereby maintaining heat-resistant storage stability while enabling low-temperature fixing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The crystallinity of the crystalline resin is enhanced by controlling crystallization parameters through the addition of a crystal nucleating agent. By changing the crystallization state and structure of the crystalline resin, the patent achieves both low-temperature fixability and maintains heat-resistant storage stability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a crystal nucleating agent is introduced to increase crystallinity of the crystalline resin, then heat-resistant storage stability is improved, but dispersibility of the crystalline resin is reduced

Engineering Contradiction:
Improveheat-resistant storage stabilityVSAvoiddispersibility of crystalline resin
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the crystallization parameters by carefully controlling the type and amount of crystal nucleating agent added. This parameter optimization enables the crystalline resin to achieve high crystallinity for heat-resistant storage stability while maintaining adequate dispersibility through controlled crystal growth

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the crystalline resin and amorphous resin are compatible before fixing, then low-temperature fixability is improved, but heat-resistant storage stability is reduced

Engineering Contradiction:
Improvefixing temperatureVSAvoidheat-resistant storage stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent segments the resin system into distinct crystalline and amorphous phases by promoting crystallization through a crystal nucleating agent. This segmentation prevents excessive compatibility between the two resin types, maintaining heat-resistant storage stability while preserving the low-temperature fixing capability through the crystalline phase

Inventive Principle:
Principle #1Segmentation

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 use of o-acetoacetaniside in toner base particles effectively improves low-temperature fixability, image density, and heat-resistant storage stability by optimizing the crystallization of the crystalline resin and maintaining the dispersibility of the colorant, resulting in improved toner performance.

Implementation Method 1

o-acetoacetaniside, which serves as a crystal nucleating agent for a crystalline resin

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

The crystalline resin melts at a melting point to plasticize an amorphous resin

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentUS10739691B2Electrostatic image developing toner and developer
Publication Date: 2020.08.11 KONICA MINOLTA INC

AI summary

An electrostatic image developing toner includes toner base particles, wherein the toner base particles contain: an amorphous polyester resin; a crystalline resin; and o-acetoacetaniside, and the content of the o-acetoacetaniside in the toner base particles is 0.1 ppm by mass or more and 200 ppm by mass or less.