Core-Shell Toner Using Wax Encapsulation for Fusing Stability

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Solution Overview

Problem

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

Innovation Solution

Encapsulating wax with a styrene acrylic latex and incorporating it into the emulsion aggregation process to create toner cores, where the wax accumulates in larger domains away from the surface and the pigment accumulates on the edges of these domains, using a core-shell structure with a borax coupling agent to enhance anchoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a styrene acrylic copolymer latex binder is used in emulsion aggregation toner, then the toner can be manufactured with good control of size and shape, but the fusing properties and shipping/storage properties must be traded off against each other

Engineering Contradiction:

Improvesize and shape controlVSAvoidfusing and shipping/storage properties

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention segments the toner particle into core and shell regions with different compositions. The core contains styrene acrylic copolymer for manufacturing control, while the shell contains polyester resin for improved fusing and shipping properties. This segmentation allows each region to optimize its function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite materials by combining styrene acrylic copolymer and polyester resin in a core-shell structure. The polyester shell layer (at least 30 wt% of total binder) provides enhanced fusing properties and shipping stability while the styrene acrylic core maintains manufacturing precision.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If the low end of the fuse window is reduced to save energy, then fusing temperature is lowered, but the toner may melt during shipping and storage

Engineering Contradiction:

Improvefusing energyVSAvoidshipping/storage stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The invention applies local quality by creating a shell layer with specific polyester resin composition that has higher melting point characteristics. This shell layer (at least 30 wt% of total binder) provides thermal stability during shipping and storage while allowing the core to facilitate low-temperature fusing, thus achieving low fusing energy consumption without compromising shipping stability.

Inventive Principle:

Principle #3Local quality

3Reliability

If lower molecular weight resins, pigment, and wax are located at the surface of toner particles, then certain functions are enhanced, but fusing and shipping properties are weakened and filming increases

Engineering Contradiction:

Improvefusing and shipping propertiesVSAvoidfilming on printer components

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention inverts the conventional distribution pattern by placing polyester resin (which provides fusing and shipping stability) in the outer shell layer rather than having lower molecular weight resins and additives concentrated at the surface. This inversion prevents filming while maintaining necessary functions through the core-shell architecture.

Inventive Principle:

Principle #13The other way round (Inversion)

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 distribution improves fusing, charging, and shipping/storage properties, reducing the likelihood of component migration and filming, while maintaining low energy fusing temperatures and stability during storage and shipping.

Implementation Method 1

encapsulating wax with a styrene acrylic latex formulation

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

emulsion aggregation process to create toner cores

Methodology Applied

Scientific EffectEmulsion aggregation: Flocculation

Implementation Method 3

borax coupling agent to enhance anchoring

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS9733582B2Toner formulation using wax encapsulated with a styrene acrylate latex formulation and method of preparing the same

Publication Date: 2017.08.15 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 wax 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.