Crystalline Polyester Encapsulated Toner for Component Migration Control

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Solution Overview

Problem

Chemically prepared toners face challenges in maintaining the distribution of lower molecular weight resins, waxes, and colorants away from the surface, leading to weakened fusing and shipping/storage properties and increased filming on printer components.

Innovation Solution

Encapsulating crystalline polyester with a styrene acrylic latex and using this encapsulated latex in the emulsion aggregation process to create toner cores, with a subsequent polymer shell, which helps anchor the pigment and wax into desired domains within the toner particle, preventing migration to the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If emulsion aggregation process is used to prepare toner, then particle size distribution and shape control are improved, but lower molecular weight resins, waxes, and colorants migrate to the toner surface

Engineering Contradiction:

Improveparticle size distribution and shape controlVSAvoidcomponent distribution within toner particle

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The toner particle is divided into multiple domains: a core domain containing lower molecular weight resins and waxes, and a shell domain containing polymer binder. This segmentation prevents migration of low molecular weight components to the surface by confining them to the core domain, while the shell provides structural integrity and controls surface properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are given different compositions and properties. The core domain has high concentration of low molecular weight resins and waxes for proper melting and flow, while the shell domain has polymer binder for structural stability. This local differentiation ensures proper component distribution without surface migration.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If low end of fuse window is reduced for energy efficiency, then fusing temperature is lowered, but toner melts during shipping and storage

Engineering Contradiction:

Improvefusing temperatureVSAvoidship/store stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The toner formulation uses a blend of polymer binders with different glass transition temperatures and low molecular weight resins with specific melting points. This parameter optimization allows the toner to maintain stability at ambient temperatures during shipping and storage, while melting at the desired low fusing temperature for energy-efficient printing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The toner is formulated as a composite material containing polymer binder, low molecular weight resins, waxes, and colorants in specific ratios. This composite structure provides both ship/store stability and low-temperature fusibility, resolving the contradiction between energy efficiency and reliability.

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 effectively reduces the migration of components to the toner surface, enhancing fusing, charging, and shipping/storage properties, and controlling color-to-color variation, resulting in improved toner performance and stability.

Implementation Method 1

preparing a monomer solution, seeding the crystalline polyester dispersion with a portion of the monomer solution, and adding an initiator solution and a remaining portion of the monomer solution to the seeded crystalline polyester dispersion

Methodology Applied

Scientific EffectEmulsion polymerization: Photopolymerisation

Implementation Method 2

A first and a second polymer emulsions as well as a pigment and a wax emulsion are combined and agglomerated to form toner cores

Methodology Applied

Scientific EffectEmulsion aggregation: Coagulation

Implementation Method 3

The first polymer emulsion is then combined and agglomerated with the pigment and wax dispersion and the encapsulated crystalline polyester latex to form toner cores

Methodology Applied

Scientific EffectPhase separation: Phase Change

Data Source

PatentUS10108101B2Toner formulation using crystalline polyester encapsulated with a styrene acrylate latex and method of preparing the same

Publication Date: 2018.10.23 LEXMARK INTERNATIONAL INC

AI summary

The present disclosure relates to a chemically prepared toner composition including a toner particle having a core including a first polymer binder, an styrene acrylate encapsulated crystalline polyester latex, a pigment, and a shell formed around the core including a second polymer binder and method to make the same. The disclosed method of preparing the toner results in a change in the distribution of the components of the toner particle wherein the lower molecular weight resins, the pigment and the wax are located away from the surface of the toner particle and the pigment is clinging to the edge of the wax domain.