Emulsion Aggregation Toner Composition for High-Speed Fusing

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Solution Overview

Problem

Conventional emulsion aggregation toners face challenges in achieving excellent half-tone rub fix and crease fix performance at high print speeds without increasing the minimum fusing temperature, which can lead to higher unscheduled maintenance rates for fuser systems.

Innovation Solution

The development of an emulsion aggregation toner comprising gel latex, high Tg latex, and wax, which fuses at temperatures between 170° C. to 220° C., achieving crease fix properties of less than 60 and half-tone rub fix properties of less than 0.15 at process speeds from 560 mm/s to 870 mm/s, thereby improving xerographic, fusing, and image quality performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional emulsion aggregation toners are used to achieve excellent half-tone rub fix and crease fix performance, then the minimum fusing temperature must be increased, but this leads to higher unscheduled maintenance rates for fuser systems

Engineering Contradiction:
Improvehalf-tone rub fix performance and crease fix performanceVSAvoidminimum fusing temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of the toner by incorporating specific gel latex (5-20 wt%), high Tg latex (60-90 wt%), and wax (5-20 wt%) in controlled ratios. This compositional parameter change enables the toner to achieve excellent rub fix and crease fix performance at lower fusing temperatures (160-200°C), resolving the contradiction between image quality and fuser temperature requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite toner system combining three distinct material components: gel latex (for low-temperature binding), high Tg latex (for structural integrity and release properties), and wax (for release and surface properties). This composite material approach synergistically combines the advantages of each component to achieve both excellent image quality and reduced fusing temperature, eliminating the need to increase temperature for improved performance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the minimum fusing temperature is increased to improve half-tone rub fix and crease fix performance, then image quality improves, but unscheduled maintenance rates for fuser systems increase

Engineering Contradiction:
Improveimage quality performanceVSAvoidunscheduled maintenance rates
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

By changing the toner composition parameters to include specific ratios of gel latex, high Tg latex, and wax, the patent enables high-quality image formation at lower fusing temperatures. This parameter optimization ensures that the toner achieves proper adhesion and release characteristics without requiring excessive heat, thereby maintaining image quality while reducing fuser thermal stress and maintenance requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of low-temperature fusing (which might compromise image quality) into a benefit by carefully selecting and optimizing the toner composition. The gel latex component provides effective binding at lower temperatures, while the high Tg latex and wax ensure proper release and surface properties. This transforms the limitation of low-temperature operation into an advantage by reducing fuser maintenance while maintaining or improving image quality.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If process speed is increased to improve productivity, then output increases, but crease fix and half-tone rub fix performance deteriorate

Engineering Contradiction:
Improveprint speedVSAvoidcrease fix and half-tone rub fix performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent optimizes the toner composition parameters to compensate for reduced thermal exposure at high print speeds. By incorporating gel latex with low-temperature binding capability and high Tg latex for structural stability, the toner maintains effective fusing even with shorter dwell times at high speeds (560-870 mm/s). The balanced composition ensures that productivity increases do not compromise image quality performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a dynamically adaptable toner system where the composite composition allows the toner to effectively fuse across a wide range of process speeds. The gel latex provides rapid initial adhesion at high speeds, while the high Tg latex ensures final set and stability. This dynamic response enables the toner to maintain consistent crease fix and rub fix performance whether operating at 560 mm/s or 870 mm/s, resolving the contradiction between productivity and image quality.

Inventive Principle:
Principle #15Dynamics

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 exhibits improved crease fix and half-tone rub fix performance at higher print speeds with reduced fusing temperatures, leading to lower unscheduled maintenance rates and superior image quality, while maintaining a narrow particle size distribution and low additive content.

Implementation Method 1

the toner fuses at about 170° C. to about 220° C. at process speeds of from about 560 mm/s to about 870 mm/s

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

followed by the coalescence of the aggregated particles at elevated temperature

Methodology Applied
Scientific EffectCoalescence: Coagulation

Implementation Method 3

forming an electrostatic latent image on a photoconductive member

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Data Source

PatentUS7862971B2Emulsion aggregation toner composition
Publication Date: 2011.01.04 XEROX CORP

AI summary

An emulsion aggregation toner having toner particles comprising a gel latex, a high Tg latex and at least one wax, wherein the toner fuses at about 170° C. to about 220° C. at process speeds of from about 560 mm/s to about 870 mm/s, wherein the toner exhibits a crease fix property of less than about 60 and a half-toner rub fix property of less than about 0.15. The toner exhibits excellent half-tone rub fix performance and crease fix at high print speeds.