Core-Shell Toner for Low-Temperature Fixing and Transport Stability

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Solution Overview

Problem

Existing electrostatic charge image developing toners face challenges in achieving compatibility between low power consumption and instant-on fixing, while also maintaining sufficient low-temperature fixing properties, and suffer from toner aggregation and clogging issues due to heat and stress during transportation in high-temperature and high-humidity environments.

Innovation Solution

The development of an electrostatic charge image developing toner with a core portion containing a first polyester resin, a colorant, and a release agent, coated with a first shell layer of a second polyester resin, and an outermost second shell layer of a polymer of an aromatic vinyl monomer and an unsaturated polyester resin, which improves heat and stress resistance, preventing aggregation and clogging, and enhancing transportability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a toner is designed for low-temperature fixing to reduce power consumption, then energy efficiency is improved, but the toner suffers from aggregation and clogging due to heat and stress during transportation in high-temperature and high-humidity environments

Engineering Contradiction:

Improvepower consumptionVSAvoidtransportability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The toner particle is divided into a core portion and a shell layer. The core contains the binder resin with low glass transition temperature for low-temperature fixing, while the shell layer contains a polymer with high heat resistance to protect the core during transportation in high-temperature environments, thus resolving the contradiction between low power consumption and transportability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The toner uses a composite structure combining a binder resin with low glass transition temperature (for low-temperature fixing) and a polymer with high heat resistance (for transport stability). This composite material approach allows the toner to achieve both low power consumption during fixing and reliable transportability in high-temperature environments.

Inventive Principle:

Principle #40Composite materials

2Speed

If the toner is designed for instant-on fixing with low glass transition temperature resin, then fixing speed is improved, but heat resistance during transportation deteriorates

Engineering Contradiction:

Improvefixing speedVSAvoidheat resistance

Core Design Contradiction:

SpeedVSTemperature

Solution Approach 1:

The toner is segmented into a core portion containing the low glass transition temperature binder resin for instant-on fixing, and an outer shell layer containing a heat-resistant polymer. This segmentation allows the inner core to provide fast fixing while the outer shell protects against heat during transportation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle have different thermal properties: the core portion has low glass transition temperature for fast fixing response, while the shell layer has high heat resistance for stable transportation. This local quality differentiation resolves the contradiction between fixing speed and heat resistance.

Inventive Principle:

Principle #3Local quality

3Reliability

If the shell layer thickness is increased to improve heat resistance, then transportability is improved, but the amount of binder resin available for low-temperature fixing is reduced

Engineering Contradiction:

ImprovetransportabilityVSAvoidlow-temperature fixing property

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention optimizes the shell layer thickness to be within 16% to 40% by weight of the total toner particle. This parameter control ensures sufficient heat resistance for transportability while maintaining adequate binder resin content for low-temperature fixing properties, thus resolving the contradiction between these two requirements.

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 toner exhibits improved heat resistance, stress resistance, and transportability, preventing clogging and ensuring high-quality image formation with enhanced low-temperature fixing properties and image quality.

Implementation Method 1

the second shell layer contains a polymer of an aromatic vinyl monomer and a third polyester resin having an ethylenic unsaturated double bond that is polymerizable with the aromatic vinyl monomer

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS8663890B2Electrostatic charge image developing toner and manufacturing method thereof, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Publication Date: 2014.03.04 FUJIFILM BUSINESS INNOVATION CORP

AI summary

Provided is an electrostatic charge image developing toner, each toner particle including a core portion, a first shell layer, and a second shell layer, wherein the core portion contains a first polyester resin, a colorant, and a release agent, the first shell layer contains a second polyester resin and covers the core portion, the second shell layer contains a polymer of an aromatic vinyl monomer and a third polyester resin having an ethylenic unsaturated double bond that is polymerizable with the aromatic vinyl monomer, and covers the first shell layer, and a total amount of the first shell layer and the second shell layer is within a range of from 16% by weight to 40% by weight of the toner particle.