Bumpy Surface Toner Particles for Improved Transfer Efficiency

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Solution Overview

Problem

Existing toner technologies face challenges with poor adhesion and cohesion, leading to reduced transfer efficiency and development stability, particularly when using external spacers which are expensive and ineffective on non-spherical toner particles.

Innovation Solution

Incorporating a cross-linked latex resin or gel into the toner particles during emulsion aggregation, forming a shell with bumps that act as spacers, improving adhesion and cohesion without external additives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external spacers are added to toner surface, then toner adhesion and cohesion are reduced, but external spacers are expensive and ineffective on non-spherical toner particles

Engineering Contradiction:

Improvetransfer efficiencyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The toner particles self-assemble bumps on their own surface through controlled aggregation of smaller particles during the toner formation process, eliminating the need for external spacer additives. This self-service approach reduces manufacturing cost while achieving the same functional effect of reduced adhesion and improved transfer efficiency.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention extracts the spacer function from external additives and integrates it directly into the toner particle structure itself. By forming bumps as an inherent part of the toner particle during manufacturing, the patent eliminates dependency on separate external spacer components, reducing both cost and complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If external spacers are used to reduce toner adhesion, then transfer efficiency improves, but external spacers require very spherical toner particles for good surface dispersion

Engineering Contradiction:

Improvetransfer efficiencyVSAvoidtoner particle shape

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

Instead of requiring spherical toner particles to support external spacers, the invention inverts the approach by allowing toner particles of various shapes to self-form bumps on their surfaces. The bump formation process adapts to different particle shapes, eliminating the spherical shape requirement while maintaining the adhesion-reduction function.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies local quality by creating bumps only on specific regions of the toner particle surface where needed for spacing function, rather than requiring the entire particle to be spherical. This localized approach allows diverse particle shapes while maintaining functional effectiveness.

Inventive Principle:

Principle #3Local quality

3Reliability

If cross-linked latex resin is incorporated into toner particles during emulsion aggregation, then bumps are formed that act as spacers, but the process complexity increases

Engineering Contradiction:

Improvedevelopment stabilityVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the bump formation process with the existing emulsion aggregation toner manufacturing process. By incorporating cross-linked latex resin into the same emulsion aggregation step used to form toner particles, the patent achieves dual functionality (toner formation and bump creation) in a single integrated process, minimizing additional complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite materials by combining cross-linked latex resin with traditional toner components during emulsion aggregation. This composite approach allows the formation of bumps with different material properties than the bulk toner, providing enhanced functionality while integrating seamlessly into the existing manufacturing process.

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

This approach enhances toner flow, reduces adhesion, and achieves greater than 95% transfer efficiency without external spacers, improving development and transfer stability across various toner shapes.

Implementation Method 1

U.S. Pat. No. 6,767,684 to Patel et al. describes an emulsion aggregation process for forming toner that combines both a latex containing a cross-linked resin and a latex containing a resin free of cross-linking.

Methodology Applied

Scientific EffectEmulsion aggregation: Coagulation

Data Source

PatentUS7662531B2Toner having bumpy surface morphology

Publication Date: 2010.02.16 GENESEE VALLEY INNOVATIONS LLC

AI summary

The toner described herein contains toner particles containing polymer, colorant and cross-linked polymer. The cross-linked polymer is incorporated at least in the shell of the toner particles. Incorporating cross-linked polymer in the shell of the toner particles provide bumps in the surface of the toner particles. These bumps can behave as spacers. Such toner can be formed by aggregating at least polymer particles and colorant particles to form core particles; aggregating at least cross-linked polymer particles to the surface of the core particles; and coalescing the resulting particles to form toner particles.