Plasma-Mediated Additive Attachment on Toner Particles

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Solution Overview

Problem

Current toner production methods, particularly batch processes, face challenges in achieving uniform and stable additive attachment, leading to batch-to-batch variations, detachment of additives over time, and changes in tribo and stability properties.

Innovation Solution

A plasma-mediated process for attaching additives to toner particles in a continuous emulsion/aggregation process, using a twin screw extruder, where a carrier gas-toner mixture is exposed to microwave radiation to generate plasma, activating the toner surface and allowing additives to attach securely, maintaining stability and tribo properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If batch reaction process is used for toner production, then additive attachment can be achieved through blending or mixing, but batch to batch variation occurs and additive attachment uniformity deteriorates

Engineering Contradiction:
Improveadditive attachment processVSAvoidadditive attachment uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical blending/mixing with a plasma-mediated chemical process. Toners are exposed to plasma in a reaction tube, creating reactive species that chemically bond additives to the toner surface. This substitution of mechanical action with plasma chemistry eliminates batch-to-batch variation and achieves uniform additive attachment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of additive attachment from physical mixing to plasma-mediated chemical bonding. By controlling plasma parameters (power, gas flow, exposure time) and reaction conditions (temperature, additive concentration), uniform and reproducible additive attachment is achieved across all batches.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If blending or mixing is used for additive attachment, then the process is simple, but additives detach over time and tribo stability changes

Engineering Contradiction:
Improveadditive attachment processVSAvoidadditive attachment stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces simple mechanical blending with plasma-mediated chemical bonding. The plasma process creates covalent or strong chemical bonds between additives and the toner surface, ensuring additives remain attached over time. This chemical bonding mechanism fundamentally improves reliability while the plasma reactor design keeps the system manageable.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a composite structure where additives are chemically bonded to the toner particle surface through plasma treatment. This forms a stable composite material where the additive-toner interface is strengthened through chemical bonding rather than physical mixing, preventing detachment over time.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If batch aggregation and coalescence is used, then toner production can be achieved, but residence time is long (up to 8 hours or more) and productivity is reduced

Engineering Contradiction:
Improvetoner production processVSAvoidproduction speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent implements a continuous toner production process where toners are continuously fed through the plasma reaction tube for additive attachment. This eliminates the batch-to-batch cycling and long residence times associated with batch aggregation and coalescence, significantly improving productivity while maintaining product quality.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent extracts the additive attachment step from the batch process and performs it in a separate continuous plasma treatment stage. This separation allows the main aggregation and coalescence processes to proceed efficiently while additive attachment occurs simultaneously in a continuous manner, reducing overall production time.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If batch process with long residence time is used, then complete reaction can be achieved, but time and cost increase

Engineering Contradiction:
Improvereaction completenessVSAvoidresidence time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent uses continuous plasma treatment to achieve complete additive attachment in a single pass through the reaction tube. The continuous flow ensures all toner particles receive uniform plasma exposure, achieving complete reaction without requiring long residence times or multiple batch cycles, thus reducing both time and cost.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces time-consuming mechanical mixing and extended batch reactions with plasma-mediated rapid chemical bonding. The high energy density of plasma enables complete additive attachment in seconds rather than hours, dramatically reducing residence time while ensuring complete reaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 process ensures consistent and stable attachment of additives, enhancing tribo charge values and aging stability of toner particles, while enabling continuous production with advantages such as faster mixing, higher yield, reduced impurities, and cost savings.

Implementation Method 1

generating plasma-inducing microwaves and conducing said microwaves in said wave guide to said resonant cavity; generating carrier gas plasma in the reaction tube on exposure of the gas to the microwave radiation

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

The plasma-mediated process can be included with a continuous process for producing an emulsion/aggregation toner, for example, in a twin screw extruder with additives attached to the toner particles by plasma treatment of the toner particles

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Data Source

PatentUS9223237B2Additive attachment on toner particles by plasma
Publication Date: 2015.12.29 XEROX CORP

AI summary

A process for attaching additives onto toner particles using plasma is described.