Toner Binder Resin Crystallinity Low Temp Fixability

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Solution Overview

Problem

Conventional toners fail to achieve low temperature fixability under low humidity, flowability under high humidity, paper type correspondence, and dot reproducibility simultaneously.

Innovation Solution

A toner formulation comprising a colorant and a binder resin with a specific composition of crystalline and non-crystalline polyesters, urea-modified polyesters, and ethyl acetate, optimized for spreadability, storage modulus, loss modulus, and crystallinity to ensure effective fixability and reproducibility across varying environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a crystalline resin is used as binder resin to achieve low temperature fixability, then fixability at low temperature is improved, but flowability under high temperature and high humidity environment deteriorates

Engineering Contradiction:
Improvefixability temperatureVSAvoidflowability
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The toner uses a composite binder resin system comprising crystalline polyester (30-70 mass%), non-crystalline polyester (10-40 mass%), and urea-modified polyester (5-20 mass%). This multi-component composite resolves the contradiction by combining the low-temperature fixability of crystalline polyester with the flowability enhancement from non-crystalline and modified polyester components, achieving both low temperature fixability and good flowability under high temperature/high humidity conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters including the crystallinity degree (10-40%), molecular weight distribution, and compositional ratios of different polyester components. By precisely controlling these parameters, particularly maintaining crystalline polyester content at 30-70 mass% and adding urea-modified polyester (5-20 mass%), the toner achieves optimal balance between low temperature fixability and flowability under varying environmental conditions.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If binder resin composition is optimized for low temperature fixability, then fixability is improved, but dot reproducibility deteriorates

Engineering Contradiction:
Improvefixability temperatureVSAvoiddot reproducibility
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The invention precisely controls the molecular weight, crystallinity degree, and compositional ratios of polyester components. The crystalline polyester has specific molecular weight range and crystallinity (10-40%), while the urea-modified polyester content is controlled at 5-20 mass%. These parameter optimizations ensure that low temperature fixability is achieved without compromising dot reproducibility, as the balanced composition provides appropriate melting characteristics and flow properties during the fixing process.

Inventive Principle:
Principle #35Parameter changes

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 exhibits excellent low temperature fixability, flowability, and dot reproducibility, maintaining performance under diverse environmental conditions while ensuring paper type correspondence.

Implementation Method 1

the polyester comprises a crystalline polyester, a non-crystalline non-modified polyester and a non-crystalline urea-modified polyester, wherein a degree of crystallinity of the toner is 10% or more

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP2972590B1Toner, image forming apparatus, process cartridge, and developer
Publication Date: 2020.07.15 RICOH CO LTD
  • EP2972590B1 patent drawingFigure 1
  • EP2972590B1 patent drawingFigure 2~3
  • EP2972590B1 patent drawing

AI summary

A toner, including: a colorant; and a binder resin, wherein a spreadability of the toner under a non-pressurized condition is 1.20 to 2.50, wherein a common logarithm of a storage modulus at 100°C (G') of the toner is 4.0 [log Pa] to 5.0 [log Pa], and wherein a ratio of a loss modulus at 100°C (G'') to the storage modulus at 100°C (G') of the toner (G''/G' = tanĪ“) is 1.1 to 2.2.