Multilayered Toner Particle with Borax Coupling Agent

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Solution Overview

Problem

Chemically prepared toners face issues with the migration of lower molecular weight resins, waxes, and colorants to the surface of toner particles, which affects fusing, color covering power, and ship/store properties, and there is a need for a formulation that reduces this migration while maintaining low fusing temperatures for energy efficiency and robustness during storage and shipping.

Innovation Solution

A multilayered toner structure is created using an emulsion aggregation process with a borax coupling agent, where the toner components are precisely controlled within the particle, with a core of amorphous polyester resin, a first layer of medium Tg/Tm polyester resin, and an outer shell of high Tg/Tm polyester resin, and the borax coupling agent is placed between the layers to anchor the shell, ensuring that low molecular weight components are contained within the particle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyester binder resins are used to form toners, then mechanical properties and color pigment compatibility are improved, but migration of lower molecular weight resins, waxes and colorants to the surface occurs, weakening fusing, color covering power and ship/store properties

Engineering Contradiction:
Improvemechanical propertiesVSAvoidmigration of lower molecular weight resins, waxes and colorants
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent employs a multilayered toner particle structure where an inner core containing lower molecular weight resins and waxes is encapsulated by an outer shell layer. This nested configuration prevents the migration of low molecular weight components to the surface while maintaining the mechanical properties and color pigment compatibility provided by polyester binder resins.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The toner particle is segmented into distinct functional layers: an inner core layer containing lower molecular weight resins, waxes and colorants, and an outer shell layer with higher molecular weight resins that prevent surface migration. This segmentation isolates the harmful migrating components within the core while maintaining desirable surface properties.

Inventive Principle:
Principle #1Segmentation

2Use of energy by stationary object

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

Engineering Contradiction:
Improvefusing temperatureVSAvoidstability during storage and shipping
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by using different resin compositions in different regions of the toner particle. The outer shell layer uses higher molecular weight resins with higher melting points to maintain structural integrity during storage and shipping, while the inner core contains lower molecular weight resins that enable low-temperature fusing. This spatial differentiation of material properties resolves the contradiction between low fusing temperature and storage stability.

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 multilayered structure effectively controls the distribution of toner components, improving fusing and ship/store properties by preventing surface migration, achieving low fusing temperatures while maintaining stability during storage and shipping, thus enhancing energy efficiency and print quality.

Implementation Method 1

the borax coupling agent is placed between the layers to anchor the shell

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

The disclosed multilayered toner particle having a borax coupling agent is prepared using an emulsion aggregation process

Methodology Applied
Scientific EffectEmulsion aggregation: Emulsion

Data Source

PatentUS10495999B2Multilayered toner particle having a borax coupling agent and method of preparing the same
Publication Date: 2019.12.03 LEXMARK INTERNATIONAL INC

AI summary

A chemically prepared multilayered toner composition, according to one example embodiment, includes a core having a first amorphous polyester resin, a second amorphous polyester resin, a colorant, and a release agent. A first layer is formed around the core wherein the first layer includes the same second amorphous polyester resin that is in the toner core. A second layer is formed on the surface of the first layer, wherein the second layer includes a third amorphous polyester resin. A borax coupling agent is between the first and second layers. In an embodiment the ratio of the second polymer in the core to second polymer in the first layer is about 50:50. The second layer can also be referred to as a shell that is formed over the toner particle having a center core, first layer and borax coupling agent. In another embodiment, the core does not contain a second amorphous polyester resin.