Toner Block Polymer Crystallinity Control

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Solution Overview

Problem

Toner formulations face challenges in achieving a balance between heat-resistant storability and low-temperature fixability, with crystalline resin-containing binders experiencing uneven crystallization that affects charging performance and durability.

Innovation Solution

A toner particle composition incorporating a styrene-acrylic resin and a block polymer with a polyester segment and a vinyl polymer segment, where the polyester segment is derived from specific monomers, ensuring well-dispersed crystallinity and controlled monomer content to enhance heat-resistant storability and low-temperature fixability while maintaining excellent charging performance and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a crystalline resin-containing binder resin is used to achieve low-temperature fixability, then the viscoelasticity drops sharply above melting point enabling low-temperature fixing, but the crystallinity declines during storage causing deterioration in heat-resistant storability

Engineering Contradiction:
Improvefixing temperatureVSAvoidheat-resistant storability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the binder resin by introducing a specific block copolymer with polyester and vinyl segments. The polyester segment content is controlled at 10-40 mass% to optimize the balance between crystallinity maintenance and low-temperature fixability, resolving the contradiction between fixing temperature and heat-resistant storability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite binder resin system combining styrene-acrylic resin with a specific block copolymer containing polyester and vinyl segments. This composite structure maintains crystallinity for heat-resistant storability while enabling low-temperature fixing through controlled melting behavior

Inventive Principle:
Principle #40Composite materials

2Reliability

If a crystal nucleating agent is added to promote crystallization and improve heat-resistant storability, then the crystallinity is maintained, but the crystals become unevenly distributed causing reduced charging performance and durability

Engineering Contradiction:
Improveheat-resistant storabilityVSAvoidcrystal distribution uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention extracts and eliminates the crystal nucleating agent from the toner composition, relying instead on the inherent crystallization properties of the specifically designed block copolymer binder resin. This removes the source of uneven crystal distribution while maintaining heat-resistant storability through the controlled crystallization behavior of the polyester segment

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution achieves a superior balance between heat-resistant storability and low-temperature fixability, along with improved charging performance and durability, by suppressing uneven distribution of the polyester segment and optimizing the block polymer content within the toner.

Implementation Method 1

the polyester segment is obtained by condensation polymerization of a monomer (a) selected from the group consisting of the monomer group A described below, and a monomer (b) selected from the group consisting of the monomer group B described below

Methodology Applied
Scientific EffectCondensation polymerization:

Data Source

PatentUS9500972B2Toner
Publication Date: 2016.11.22 CANON KK

AI summary

A toner that comprises a toner particle that contains a binder resin that contains a styrene-acrylic resin and a block polymer, wherein the block polymer has a polyester segment and a vinyl polymer segment; the polyester segment is obtained by condensation polymerization of: a monomer (a) selected from a group consisting of a prescribed monomer group A; and a monomer (b) selected from a group consisting of a prescribed monomer group B, and the content in the polyester segment of the substructure originating with the monomer (b) as calculated from the following formula is from at least 1.0 mol % to not more than 30.0 mol %: {monomer (b) [mol]/(monomer (a) [mol]+monomer (b) [mol])}×100.