Polymerized Toner Core-Shell Structure for Heat-Stable Low-Temp Fixing

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Solution Overview

Problem

Existing toners for electrostatic image development lack a balance between heat-resistant storage stability and low-temperature fixability, making them inadequate for high-speed printing with low power consumption.

Innovation Solution

A method for producing polymerized toners involving multi-stage suspension polymerization, where a second-stage polymerizable monomer with a lower glass transition temperature is added during the first-stage polymerization, followed by a third-stage polymerization with a polymerization initiator and monomer, to achieve a balanced glass transition temperature distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the fixing temperature is decreased to reduce energy consumption, then power consumption is reduced, but toner storage stability deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidtoner storage stability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The toner particle is divided into a core component and a shell component with distinct functions. The core component (first polymerizable monomer) provides storage stability with higher Tg, while the shell component (second polymerizable monomer) enables low-temperature fixability with lower Tg. This segmentation allows the toner to satisfy both contradictory requirements simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are given different properties: the core has higher glass transition temperature for thermal stability during storage, while the shell has lower glass transition temperature for easy fixation. This local differentiation of material properties resolves the contradiction between storage stability and fixability.

Inventive Principle:

Principle #3Local quality

2Productivity

If the fixing temperature is increased to enable high-speed printing, then printing speed is improved, but energy consumption increases

Engineering Contradiction:

Improveprinting speedVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

The glass transition temperature parameter of the toner is optimized by combining monomers with different Tg values. The shell component's lower Tg allows fixation at reduced temperatures, enabling high-speed printing without increasing energy consumption, as the toner can be fixed quickly at lower temperatures rather than requiring prolonged high-temperature exposure.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single-component toner is used to simplify the structure, then manufacturing complexity is reduced, but the balance between storage stability and fixability deteriorates

Engineering Contradiction:

Improvetoner structure complexityVSAvoidbalance between storage stability and fixability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The toner is segmented into core and shell components with different polymerizable monomers. This segmentation enables the simultaneous achievement of storage stability (core) and fixability (shell), resolving the contradiction between structural simplicity and functional balance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The toner uses a composite structure combining different polymer materials with complementary properties. The core uses a polymerizable monomer providing thermal stability, while the shell uses a different polymerizable monomer providing low-temperature fixability, creating a composite material that balances both requirements.

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

The method results in toners with excellent heat-resistant storage stability and low-temperature fixability, optimizing both properties for high-speed printing with reduced energy consumption.

Implementation Method 1

a first-stage polymerization step of carrying out suspension polymerization by using the suspension, in the presence of a polymerization initiator

Methodology Applied

Scientific EffectSuspension polymerization: Photopolymerisation

Implementation Method 2

a second-stage polymerization step of carrying out suspension polymerization by further adding a second-stage polymerizable monomer satisfying the following formula (1), when a polymerization conversion rate in the first-stage polymerization step becomes 20 to 80%

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS9454093B2Method for producing a polymerized toner

Publication Date: 2016.09.27 ZEON CORP

AI summary

Disclosed is a method for producing a polymerized toner, wherein the method comprises: a suspension step of obtaining a suspension in which droplets of a first-stage polymerizable monomer composition containing at least a first-stage polymerizable monomer and a colorant are dispersed, by suspending the first-stage polymerizable monomer composition in an aqueous dispersion medium containing a dispersion stabilizer; a first-stage polymerization step of carrying out suspension polymerization by using the suspension, in the presence of a polymerization initiator; and a second-stage polymerization step of carrying out suspension polymerization by further adding a second-stage polymerizable monomer satisfying the following formula (1), when a polymerization conversion rate in the first-stage polymerization step becomes 20 to 80%:Tg1>Tg2. Formula (1):