Crystalline Toner Resin Storage Modulus Control for Fixing Uniformity

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Solution Overview

Problem

Toner fixing irregularities occur during high-speed printing due to the fragility and sharp melt properties of crystalline resins used in electrophotographic methods, leading to uneven heat and pressure distribution, which affects image quality and low-temperature fixability.

Innovation Solution

A toner formulation with a crystalline resin that controls the storage modulus within specific ranges to reduce pressure dependency and achieve uniform crystal states, using a filler like cellulose or lignin/cellulose complex to enhance the crystallinity and stability of the resin, thereby improving low-temperature fixability and reducing fixing irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If crystalline resin is used in toner binder to achieve low-temperature fixability, then fixing temperature is reduced, but fixing irregularities occur due to fragility and sharp melt properties

Engineering Contradiction:
Improvefixing temperatureVSAvoidfixing uniformity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention changes the physical parameters of the crystalline resin by controlling its storage modulus at specific temperatures and frequencies. By adjusting G′(Tp−30, 10 Hz)/G′(Tp−5, 0.01 Hz) to ≤1.40 and G′(Tp−5, 10 Hz)/G′(Tp−5, 0.01 Hz) to ≤2.20, the resin maintains appropriate rigidity across the fixing temperature range, preventing both excessive softening and fragility, thus resolving the contradiction between low-temperature fixability and fixing uniformity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite binder resin system combining crystalline resin with amorphous resin in specific proportions (crystalline resin 30-100 parts by weight, amorphous resin 0-70 parts by weight). This composite structure allows the crystalline resin to provide low-temperature melting while the amorphous resin contributes to uniformity and reduces fixing irregularities, effectively resolving the contradiction

Inventive Principle:
Principle #40Composite materials

2Temperature

If large quantities of crystalline resin are used to improve low-temperature fixability, then fixing temperature is reduced further, but crystal state uniformity deteriorates causing melting point deviation

Engineering Contradiction:
Improvefixing temperatureVSAvoidcrystal state uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The invention controls the storage modulus parameters to ensure uniform crystal state. By maintaining G′(Tp−30, 10 Hz)/G′(Tp−5, 0.01 Hz) ≤1.40, the crystalline resin maintains consistent mechanical properties across different temperatures, preventing melting point deviation and ensuring uniform crystal states even when used in large quantities (30-100 parts by weight)

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies different functional requirements to different aspects of the crystalline resin: the storage modulus ratios control the local mechanical response at specific temperature-frequency conditions, while the overall composition controls the bulk crystal state uniformity. This localized control of properties ensures both low-temperature fixability and compositional stability

Inventive Principle:
Principle #3Local quality

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 controlled storage modulus and filler addition result in improved low-temperature fixability and reduced fixing irregularities, enabling high-quality images during high-speed printing while maintaining energy efficiency.

Implementation Method 1

toners have been developed that use crystalline resins having the 'sharp melt property' of softening abruptly at the melting point in the toner binder resin

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

an endothermic peak derived from the crystalline resin exists in a temperature-endothermic quantity curve obtained by differential scanning calorimetry of the toner

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

in viscoelasticity measurement of the toner with Tp being a peak temperature of the endothermic peak derived from the crystalline resin

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS11112713B2Toner
Publication Date: 2021.09.07 CANON KK

AI summary

A toner including a toner particle containing a binder resin, wherein the binder resin contains a crystalline resin, and in viscoelasticity measurement of the toner with Tp being a peak temperature of an endothermic peak derived from the crystalline resin in DSC of the toner, given G′(Tp−5, 0.01 Hz) as a storage modulus at a temperature of Tp−5° C. and a frequency of 0.01 Hz, G′(Tp−5, 10 Hz) as a storage modulus at a temperature of Tp−5° C. and a frequency of 10 Hz, and G′(Tp−30, 10 Hz) as a storage modulus at a temperature of Tp−30° C. and a frequency of 10 Hz, the following formulae are satisfied:G′(Tp−30,10 Hz)/G′(Tp−5,0.01 Hz)≤1.40G′(Tp−5,10 Hz)/G′(Tp−5,0.01 Hz)≤2.20.