Emulsion Aggregation Toner for Low-Temperature Fusing

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Solution Overview

Problem

Existing styrene acrylate emulsion aggregation toners for single component developer image forming devices face challenges in achieving excellent print quality and gloss at low fusing temperatures, with a need for toners that exhibit high transfer efficiency and appropriate triboelectric charge.

Innovation Solution

Development of styrene acrylate emulsion aggregation toner particles with a specific composition including a styrene acrylate polymer binder, wax, and colorants, having a volume average particle size of 5-10 μm, high circularity, and an onset glass transition temperature of 45-65°C, which are free of silica and feature a core-shell structure, enabling efficient triboelectric charging and image development.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If styrene acrylate emulsion aggregation toners are used in single component developer image forming devices, then the toners can be made with uniform sizes and are environmentally friendly, but they fail to achieve excellent print quality and gloss at low fusing temperatures

Engineering Contradiction:
Improveuniform particle sizeVSAvoidprint quality and gloss
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the glass transition temperature parameter of the binder resin to a specific range (45-65°C) to achieve both low fusing temperature and excellent print quality. This parameter optimization allows the toner to maintain uniform particle size while achieving superior gloss and image quality at low fusing temperatures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite toner formulation combining styrene acrylate polymer binder with specific wax components and colorants. This composite structure enables the toner to achieve excellent flow properties, low cohesivity, and superior print quality while maintaining uniform particle size distribution

Inventive Principle:
Principle #40Composite materials

2Device complexity

If conventional toner formulations are used, then the toners can be made with simple composition, but they exhibit poor transfer efficiency and inappropriate triboelectric charge for single component development

Engineering Contradiction:
Improvetoner compositionVSAvoidtransfer efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent optimizes the molecular weight parameters of the binder resin (number average molecular weight and weight average molecular weight with specific distribution) to achieve appropriate triboelectric charge and high transfer efficiency. These parameter changes enable effective single component development while maintaining relatively simple toner composition

Inventive Principle:
Principle #35Parameter changes

3Use of energy by stationary object

If toners are designed for low fusing temperature, then energy consumption is reduced, but print quality and gloss are compromised

Engineering Contradiction:
Improvefusing temperatureVSAvoidimage quality and gloss
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent changes the glass transition temperature of the binder resin to a specific range (45-65°C) that enables low fusing temperature operation. This parameter optimization, combined with specific molecular weight control, allows the toner to achieve excellent gloss and image quality while reducing fusing temperature and energy consumption

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 particles demonstrate high transfer efficiency, low cohesivity, and excellent flow properties, achieving superior image quality and stability in single component development processes, particularly in devices with low oil or oil-less fuser designs.

Implementation Method 1

by making a latex in water using an emulsion polymerization

Methodology Applied
Scientific EffectEmulsion polymerization:

Implementation Method 2

The aggregated toner particles are optionally heated to enable coalescence/fusing

Methodology Applied
Scientific EffectCoalescence:

Implementation Method 3

wherein the toner particles have a volume average particle size of from about 5 μm to about 10 μm, an average circularity of about 0.95 to about 0.99, a volume and number geometric standard deviation (GSDv and n) of from about 1.10 to about 1.30, and an onset glass transition temperature of from about 45° C. to about 65° C.

Methodology Applied
Scientific EffectTriboelectric effect: Triboelectric Effect

Implementation Method 4

each of the cyan toner, magenta toner, yellow toner and black toner are comprised of emulsion aggregation toner particles comprising a styrene acrylate polymer binder, at least one release agent and at least one colorant

Methodology Applied
Scientific EffectRelease agent mechanism:

Data Source

PatentUS7402370B2Single component developer of emulsion aggregation toner
Publication Date: 2008.07.22 GENESEE VALLEY INNOVATIONS LLC

AI summary

A toner for developing electrostatic images in a single component development (SCD) system free of carrier and including emulsion aggregation toner particles of a styrene acrylate polymer binder, at least one release agent and at least one colorant, wherein the toner particles have a volume average particle size of from about 5 μm to about 10 μm, an average circularity of about 0.95 to about 0.99, a volume and number geometric standard deviation (GSDv and n) of from about 1.10 to about 1.30, and an onset glass transition temperature of from about 45° C. to about 65° C., is ideally suited for forming an image using a single component image forming device.