Core Shell Toner with IPN Microgel for Low-Temperature Fusing

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Solution Overview

Problem

Chemically prepared toners face challenges in simultaneously achieving low-temperature fusing while maintaining robustness for shipping and storage conditions, as existing formulations often compromise between fusing properties and ship/store test performance due to limitations with polyester and styrene-acrylic latexes.

Innovation Solution

Incorporating a core shell styrene acrylic latex with an encapsulated interpenetrating polymer network (IPN) microgel as a softening agent, which promotes low-temperature fusing without compromising shipping and storage robustness by using a self-crosslinkable oil and silane coupling system within the toner core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polyester resin is used as binder to achieve low-temperature fusing, then fusing temperature is reduced, but ship/store stability deteriorates due to melting during storage

Engineering Contradiction:
Improvefusing temperatureVSAvoidship/store stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The toner is divided into core and shell segments with different functional compositions. The core contains low-melting polyester resin for low-temperature fusing, while the shell contains high-melting polyester resin to provide thermal stability during storage and shipping, preventing the toner from melting in warm conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite material system combining two different polyester resins with distinct melting points. The low-melting polyester resin (100-150°C) enables energy-efficient fusing, while the high-melting polyester resin (160-200°C) ensures structural integrity and prevents caking during storage, creating a material that exhibits both low-temperature fusibility and high-temperature stability.

Inventive Principle:
Principle #40Composite materials

2Temperature

If crystalline polyester resin is used as plasticizing agent to promote low-temperature fusing, then fusing properties improve, but manufacturing complexity increases due to expensive and time-consuming incorporation process

Engineering Contradiction:
Improvefusing temperatureVSAvoidmanufacturing process simplicity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts the plasticizing function from a separate crystalline polyester resin additive and integrates it directly into the binder polymer structure itself. By incorporating flexible chain segments within the polyester resin molecules, the material achieves low-temperature fusing without requiring separate plasticizer incorporation steps, simplifying the manufacturing process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of binder and plasticizing agent into a single integrated polyester resin system. The binder polymer contains built-in flexible segments that provide plasticizing effects, eliminating the need for separate plasticizer addition and simplifying the formulation and manufacturing processes while maintaining low-temperature fusing capability.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If more polyester resin is added to lower fusing temperature, then fusing properties improve, but ship/store performance deteriorates due to short chain migration speed

Engineering Contradiction:
Improvefusing temperatureVSAvoidship/store performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The polyester resin system is segmented into two distinct components with different thermal properties: a low-melting fraction (100-150°C) that migrates quickly to enable low-temperature fusing, and a high-melting fraction (160-200°C) that remains stable during storage. This segmentation allows each component to perform its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the thermal parameters of the polyester resin by using a bimodal distribution of melting points. By controlling the proportion and characteristics of low-melting and high-melting polyester resin fractions, the system achieves optimal balance between fusing temperature and storage stability, with the low-melting fraction providing quick response during fusing while the high-melting fraction ensures long-term stability.

Inventive Principle:
Principle #35Parameter changes

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 toner formulation achieves energy-efficient low-temperature fusing while maintaining stability during shipping and storage, ensuring good print quality and resistance to higher printing speeds, thus addressing the limitations of previous toner formulations.

Implementation Method 1

a core shell styrene acrylic latex having an encapsulated interpenetrating polymer network (IPN) microgel

Methodology Applied
Scientific EffectInterpenetrating polymer network (IPN):

Implementation Method 2

self-crosslinkable oil and silane coupling system within the toner core

Methodology Applied
Scientific EffectSelf-crosslinking:

Implementation Method 3

self-crosslinkable oil and silane coupling system within the toner core

Methodology Applied
Scientific EffectCrosslinking:

Data Source

PatentUS10048609B2Toner formulation including a softening agent and method of preparing the same
Publication Date: 2018.08.14 LEXMARK INTERNATIONAL INC

AI summary

A chemically prepared core shell toner formulation for use in electrophotography having an inventive softening agent consisting of a core shell latex having an encapsulated interpenetrating polymer network microgel in the core of the toner is disclosed. Having this core shell latex with an encapsulated IPN microgel in the core of the toner results in a toner that can simultaneously fuse at a desirable low temperature and survive the temperature extremes associated with shipping and storage.