Toner Production via Suspension Polymerization with Microparticle Inhibitor

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Solution Overview

Problem

The existing methods for producing toners in electrophotography face challenges in minimizing the generation of small diameter microparticles as by-products, which lead to reduced productivity and printing performance due to clogging and adhesive issues in developing devices.

Innovation Solution

A method involving suspension polymerization with a metal-containing organic pigment and the use of a metal chelate forming agent and an inhibitor of small diameter microparticle production, within specific concentration ranges, to inhibit the generation of small diameter microparticles during the toner production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If suspension polymerization is used to produce toner particles, then spherical colored resin particles with small particle diameter can be produced, but small diameter microparticles are generated as by-products

Engineering Contradiction:

Improveparticle diameter controlVSAvoidsmall diameter microparticles

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A metal chelate forming agent is introduced as an intermediary substance that binds to metal ions in the polymerizable monomer composition, preventing these metal ions from catalyzing the formation of small diameter microparticles during the suspension polymerization process

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical environment parameters by adding a metal chelate forming agent that alters the metal ion availability and reactivity in the polymerization system, thereby controlling microparticle generation

Inventive Principle:

Principle #35Parameter changes

2Productivity

If small diameter microparticles are generated during polymerization, then productivity decreases due to clogging in washing treatment, but filtering members can be used to remove particles

Engineering Contradiction:

Improvetoner production efficiencyVSAvoidwashing treatment complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The metal chelate forming agent is added before polymerization to prevent the formation of small diameter microparticles in the first place, eliminating the need for complex filtration and washing steps that would otherwise be required to remove these particles

Inventive Principle:

Principle #10Preliminary action

3Reliability

If small diameter microparticles are present in toner, then printing performance deteriorates due to adhesive force on developing device members, but particle generation can be reduced by optimizing polymerization conditions

Engineering Contradiction:

Improveprinting performanceVSAvoidpolymerization process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The metal chelate forming agent acts as an intermediary that specifically targets and neutralizes metal ion catalysts responsible for microparticle formation, maintaining simple polymerization conditions while ensuring high printing performance by preventing microparticle generation

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces the generation of small diameter microparticles, simplifies the washing treatment, and enhances toner productivity and printing performance by preventing clogging and adhesive issues in developing devices.

Implementation Method 1

the polymerizable monomer composition is charged into an aqueous dispersion medium containing a dispersion stabilizer to disperse the composition. Furthermore, a high-speed mixer or the like is used to apply a high shear thereto, thereby forming droplets of the polymerizable monomer composition. Thereafter, the aqueous dispersion medium in which the polymerizable monomer composition, which is in a droplet form, is dispersed undergoes polymerization in the presence of a polymerization initiator.

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is suspended into an aqueous dispersion medium containing a dispersion stabilizer to yield a suspension wherein droplets of the polymerizable monomer composition are dispersed

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS8092975B2Method for producing toner for devoloping electrostatic image

Publication Date: 2012.01.10 ZEON CORP

AI summary

Provided is a method for producing a toner for developing electrostatic image which inhibits the generation of small diameter microparticles as a by-product in the polymerization for the toner, which includes easy or simple washing treatment (washing/filtration/dehydration), and which is excellent in productivity.The method is a method for producing a toner for developing electrostatic image comprising a suspending step of suspending a polymerizable monomer composition containing at least a polymerizable monomer and a colorant into an aqueous dispersion medium containing a dispersion stabilizer to yield a suspension wherein droplets of the polymerizable monomer composition are dispersed, and a step of subjecting the suspension to suspension polymerization in the presence of a polymerization initiator to yield colored resin particles, wherein the colorant is a metal-containing organic pigment, and when the suspension polymerization is performed, the suspension contains 0.01 to 1 part by weight of an inhibitor of small diameter microparticle production for 100 parts by weight of the polymerizable monomer.