Core-Shell Toner Particles for Low Fusing Temperature

Solution Overview

Problem

Conventional toner particles with high crystalline resin content face issues with charge maintainability and resistivity, particularly in humid environments, due to the low resistivity of crystalline resin, which affects their fusing temperature and performance.

Innovation Solution

A toner particle design with a core comprising 10-35% crystalline resin and a shell of 45-70% amorphous resin, where the shell encapsulates the core, preventing crystalline resin from reaching the surface and maintaining low resistivity, thereby achieving lower fusing temperatures and improved charge maintainability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the amount of crystalline resin in toner particles is increased to lower fusing temperature, then energy efficiency improves, but charge maintainability deteriorates

Engineering Contradiction:

Improvefuser power consumptionVSAvoidcharge maintainability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The toner particle is divided into a core containing crystalline resin (10-35% by weight) and a shell containing amorphous resin (45-70% by weight). This segmentation allows the crystalline resin to be isolated within the core, preventing it from reaching the surface and causing charge maintainability issues, while still providing the low fusing temperature benefit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are given different compositions: the core contains high crystalline resin content for low fusing temperature, while the shell contains amorphous resin for good charge maintainability. This local differentiation allows each region to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

2Use of energy by stationary object

If the amount of crystalline resin is increased to achieve lower fusing temperature, then energy efficiency improves, but toner charge deteriorates

Engineering Contradiction:

Improvefusing temperatureVSAvoidtoner charge

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The toner particle is segmented into a core containing crystalline resin (10-35% by weight) and a shell containing amorphous resin (45-70% by weight). This segmentation allows the crystalline resin to be isolated within the core, preventing it from reaching the surface and causing charge maintainability issues, while still providing the low fusing temperature benefit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are given different compositions: the core contains high crystalline resin content for low fusing temperature, while the shell contains amorphous resin for good charge maintainability. This local differentiation allows each region to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

3Use of energy by stationary object

If crystalline resin content is increased beyond 15% to lower fusing temperature, then energy efficiency improves, but charge maintainability sharply decreases

Engineering Contradiction:

Improvefusing temperatureVSAvoidcharge maintainability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The toner particle is segmented into a core containing crystalline resin (10-35% by weight) and a shell containing amorphous resin (45-70% by weight). This segmentation allows the crystalline resin to be isolated within the core, preventing it from reaching the surface and causing charge maintainability issues, while still providing the low fusing temperature benefit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are given different compositions: the core contains high crystalline resin content for low fusing temperature, while the shell contains amorphous resin for good charge maintainability. This local differentiation allows each region to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

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 solution results in toner particles with a minimum fusing temperature 10-30°C lower than conventional toners, maintaining charge stability and performance comparable to control toners, while avoiding the drawbacks of high crystalline resin content.

Implementation Method 1

According to convention, it was thought that the plasticization effect of the crystalline resin occurs only when the crystalline resin is incorporated into the amorphous resin during fusing.

Methodology Applied

Scientific EffectPlasticization:

Implementation Method 2

a shell over at least a portion of the core including at least a second amorphous resin

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

The toners may then be fused to the substrate by heating the toner with a contact fuser or a non-contact fuser, wherein the transferred heat melts the toner mixture onto the substrate.

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS8592119B2Super low melt toner with core-shell toner particles

Publication Date: 2013.11.26 XEROX CORP

AI summary

A toner particle having a core and a shell, and a method for making the toner particle. The core includes a crystalline resin and the shell includes an amorphous resin. The shell is substantially to completely free of the crystalline resin. The toner particle permits inclusion of greater amounts of crystalline resin materials in the core, thereby lowering the minimum fusing temperature of the toner formed from the particles.