Toner Formulation Using Core Shell Latex for Low Temperature Fusing

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Solution Overview

Problem

Chemically prepared toners face challenges in achieving low fusing temperatures while maintaining robustness for shipping and storage conditions, as existing plasticizing agents are either expensive or compromise the toner's ship/store properties.

Innovation Solution

Incorporating a core shell styrene acrylic latex with a liquid gel core as a plasticizing agent, which allows for low temperature fusing while maintaining the toner's stability during shipping and storage, and is cost-efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If polyester resin is used as a plasticizing agent to lower fusing temperature, then energy efficiency is improved, but ship/store properties deteriorate due to short chain migration speed

Engineering Contradiction:
Improvefusing temperatureVSAvoidship/store properties
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the plasticizing agent from conventional polyester resin to a specific mixture of amorphous polyester resin and crystalline polyester resin in controlled proportions (0.1-10 wt% amorphous, 90-90 wt% crystalline). This parameter change allows the toner to fuse at lower temperatures while the crystalline structure prevents excessive chain migration during storage, resolving the contradiction between energy efficiency and ship/store reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite plasticizing system by combining amorphous polyester resin and crystalline polyester resin in specific ratios. The amorphous component provides low-temperature fusion capability while the crystalline component maintains structural integrity during storage. This composite approach allows simultaneous achievement of low fusing temperature and good ship/store properties

Inventive Principle:
Principle #40Composite materials

2Reliability

If crystalline polyester resin is used as plasticizing agent to maintain ship/store properties, then stability is improved, but fusing temperature cannot be sufficiently lowered

Engineering Contradiction:
Improveship/store propertiesVSAvoidfusing temperature
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the proportion of crystalline polyester resin to be 90-99.9 wt% of the total plasticizing agent, with amorphous polyester resin making up 0.1-10 wt%. This specific parameter range allows the crystalline structure to dominate for storage stability while the amorphous component provides sufficient low-temperature fusion capability, resolving the contradiction between stability and energy efficiency

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If polyester resin amount is increased to lower fusing temperature, then energy efficiency is improved, but toner cannot survive shipping and storage temperature extremes

Engineering Contradiction:
Improvefusing temperatureVSAvoidtemperature extremes during shipping and storage
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent precisely controls the total plasticizing agent content at 0.1-10 wt% of toner weight, with a specific breakdown between amorphous (0.1-10 wt%) and crystalline (90-99.9 wt%) polyester resins. This parameter control ensures enough plasticizer for low-temperature fusion while limiting total content to prevent excessive softening that would cause caking during shipping and storage temperature extremes

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If low molecular weight polyester resin is used to open the low temperature end of fuse window, then energy efficiency is improved, but ship/store properties are compromised

Engineering Contradiction:
Improvelow temperature fusingVSAvoidship/store properties
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent creates a composite resin system where low molecular weight amorphous polyester resin (providing low-temperature fusion) is combined with higher molecular weight crystalline polyester resin (providing storage stability). The crystalline component's ordered structure prevents the short-chain amorphous resin from migrating excessively during storage, allowing both low-temperature fusion and good ship/store properties to coexist

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

The core shell styrene acrylic latex enables toners to fuse at energy-efficient low temperatures while ensuring print quality and stability during storage and shipping, without compromising ship/store properties.

Implementation Method 1

Incorporating a core shell styrene acrylic latex with a liquid gel core as a plasticizing agent, which allows for low temperature fusing while maintaining the toner's stability during shipping and storage

Methodology Applied
Scientific EffectPlasticizing:

Implementation Method 2

The use of a styrene-acrylic copolymer latex binders and in toner formulations unfortunately requires a tradeoff between the toner's fusing properties and its shipping and storage properties... The core shell styrene acrylic latex enables toners to fuse at energy-efficient low temperatures

Methodology Applied
Scientific EffectPlasticization:

Implementation Method 3

the toner must also be able to survive the temperature and humidity extremes associated with storage and shipping—commonly called the ship/store test

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 4

One process for preparing a CPT is by emulsion aggregation. Emulsion aggregation is carried out in an aqueous system resulting in good control of both the size and shape of the toner particles

Methodology Applied
Scientific EffectEmulsion polymerization:

Data Source

PatentUS9869944B2Toner formulation and method of preparing the same
Publication Date: 2018.01.16 LEXMARK INTERNATIONAL INC

AI summary

A chemically prepared toner composition made up of a toner particle with a core having a first polymer binder, a monomer free radical polymerization formed core shell styrene acrylic latex having a liquid gel core, a pigment, a wax, and a shell formed around the core including a second polymer binder and method to make the same is disclosed. An optional borax coupling agent can be placed between the outer surface of the core and the shell to assist in the binding of the polymer found in the shell onto the surface of the toner core containing the first polymer.