Toner Phase Separation for Low-Temp Fixing and Adhesion Control

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Solution Overview

Problem

Conventional toners face challenges in achieving both low-temperature fixability and suppressing ejected paper adhesion, particularly when using crystalline polyester as a plasticizer, which often results in lowered glass transition temperature and increased heat requirements for thick paper, leading to adhesion issues during double-sided printing.

Innovation Solution

A toner formulation with specific thermal characteristics, where Tg1 is 53° C. or lower and Tg2 is 55° C. or higher, achieved by controlling the compatibility and phase separation between the binder resin and plasticizer, utilizing a polyester resin with an imidazolium or ammonium salt plasticizer, to ensure adequate low-temperature fixability and reduced ejected paper adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If crystalline polyester is used as a plasticizer to improve low-temperature fixability, then the glass transition temperature is lowered, but the storage stability deteriorates and ejected paper adhesion occurs

Engineering Contradiction:

Improveglass transition temperatureVSAvoidstorage stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention divides the plasticizer system into two distinct components: crystalline polyester (providing low-temperature fixability by lowering Tg) and amorphous polyester (maintaining storage stability). This segmentation allows each component to perform its specific function without the adverse effects of complete dissolution and Tg reduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite plasticizer system comprising crystalline polyester and amorphous polyester in specific proportions (crystalline polyester 10-40 parts, amorphous polyester 60-30 parts per 100 parts binder resin). This composite approach combines the benefits of both materials: crystalline polyester lowers Tg for low-temperature fixing, while amorphous polyester maintains storage stability by preventing excessive Tg reduction

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If fixing temperature is increased to adapt to thick paper, then the adaptability to various media is improved, but the heat capacity increases and ejected paper adhesion occurs

Engineering Contradiction:

Improveadaptability to various mediaVSAvoidfixing temperature

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The invention changes the thermal parameters of the toner by controlling the glass transition temperature through the plasticizer composition. By maintaining Tg1 at 40-53°C and Tg2 at 55-65°C through the crystalline/amorphous polyester ratio, the toner achieves low-temperature fixability, allowing fixing at lower temperatures even for thick paper, thereby preventing ejected paper adhesion while maintaining adaptability

Inventive Principle:

Principle #35Parameter changes

3Temperature

If the Tg of the toner layer is lowered for low-temperature fixing, then the low-temperature fixability is improved, but the ejected paper adhesion increases

Engineering Contradiction:

Improvefixing temperatureVSAvoidejected paper adhesion

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention performs preliminary action by controlling the phase state of the plasticizer components before fixing. The crystalline polyester remains crystalline and the amorphous polyester remains amorphous at storage temperature, preventing premature dissolution and Tg reduction. During fixing, the controlled melting and phase transition occur only when needed, preventing ejected paper adhesion while achieving low-temperature fixability

Inventive Principle:

Principle #10Preliminary action

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 toner effectively suppresses ejected paper adhesion while maintaining improved low-temperature fixability, by controlling the glass transition temperatures through the compatibility and phase separation of the binder resin and plasticizer, addressing the limitations of conventional toners.

Implementation Method 1

controlling the compatibility and phase separation between the binder resin and plasticizer

Methodology Applied

Scientific EffectPhase separation:

Implementation Method 2

Tg1 is 53° C. or lower and Tg2 is 55° C. or higher, wherein in DSC measurement using the toner as a sample

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 3

the temperature of the toner is raised for the first time at a rate of temperature increase of 10° C./min

Methodology Applied

Scientific EffectThermal heating: Heating

Data Source

PatentUS11249410B2Toner

Publication Date: 2022.02.15 CANON KK

AI summary

A toner having an adequate storage stability and adequately suppressing an ejected paper adhesion, while achieving improving low-temperature fixability, has a toner particle containing a binder resin and a plasticizer, wherein Tg1 is 53° C. or lower and Tg2 is 55° C. or higher, in DSC measurement using the toner as a sample, when the following steps (i) to (iii) are performed: (i): the temperature of the toner is raised for the first time at a rate of temperature increase of 10° C./min, (ii): after the step (i), the temperature of the toner is lowered at a rate of temperature decrease of 10° C./min, (iii): after the step (ii), the temperature of the toner is raised for the second time at a rate of temperature increase of 10° C./min, Tg1 represents a glass transition temperature measured at the step (i), and Tg2 represents a glass transition temperature measured at the step (iii).