Toner Binder Resin Cross-Linking for Low-Temperature Fixing

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Solution Overview

Problem

Current toner technologies face challenges in achieving low-temperature fixing properties while maintaining heat-resistant storage and high hot offset resistance, which is essential for energy conservation and improved image quality in electrophotographic processes.

Innovation Solution

A toner with a binder resin containing secondary modified polyester, derived from cross-linking primary modified polyester with an active hydrogen group-containing compound, is developed. This toner has a glass transition temperature between 40°C to 55°C, allowing for improved low-temperature fixing and hot offset resistance, and is produced by granulating in an aqueous medium with specific molecular weight ranges to optimize heat properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the fixing temperature of the toner is decreased to achieve low-temperature fixing and energy conservation, then energy consumption is reduced and fixing speed is improved, but hot offset resistance and heat-resistant storage property are degraded

Engineering Contradiction:
Improveenergy consumptionVSAvoidhot offset resistance
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent changes the glass transition temperature parameter of the binder resin to a specific range (40°C to 55°C) to achieve optimal low-temperature fixing while maintaining hot offset resistance. This parameter optimization allows the toner to fix at lower temperatures without sacrificing thermal stability during storage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite binder resin systems combining polyester resins with specific molecular weight distributions (including both low and high molecular weight components) to achieve synergistic effects. The composite structure provides both low-temperature fixing capability and hot offset resistance.

Inventive Principle:
Principle #40Composite materials

2Temperature

If the molecular weight of the toner binder is reduced or the ratio of low molecular weight components is increased to improve low-temperature fixing property, then fixing temperature is lowered, but storage stability is degraded and fusion during running occurs

Engineering Contradiction:
Improvefixing temperatureVSAvoidstorage stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent optimizes the molecular weight distribution parameters of the binder resin, specifically controlling the ratio of low molecular weight to high molecular weight components. The glass transition temperature is adjusted to 40°C to 55°C, which allows low-temperature fixing while preventing storage instability and fusion during operation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If releasing agents such as low-molecular-weight polypropylene are added to the toner particles to provide offset preventing property, then offset resistance is improved, but the toner composition becomes more complex and manufacturing difficulty increases

Engineering Contradiction:
Improveoffset resistanceVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent achieves offset resistance by optimizing the glass transition temperature and molecular weight distribution of the binder resin itself, rather than adding separate releasing agents. This approach maintains offset resistance while simplifying the toner composition and manufacturing 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 achieves excellent low-temperature fixing properties and hot offset resistance, enabling high-quality image formation with prolonged durability and energy efficiency, meeting the requirements of advanced low-temperature fixing technologies.

Implementation Method 1

the binder resin contains secondary modified polyester which can be obtained by cross-linking a primary modified polyester (B) derived from polyester as a precursor (A)

Methodology Applied
Scientific EffectCross-linking reaction: Chemical Bonding

Implementation Method 2

the toner is granulated in an aqueous medium

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 3

fixing step in which the toner is fixed on the paper

Methodology Applied
Scientific EffectThermal melting: Melting

Implementation Method 4

thermal-roller type fixing apparatuses

Methodology Applied
Scientific EffectThermal energy transfer: Heating

Data Source

PatentEP1880250B8Toner and image forming method using the same
Publication Date: 2012.10.24 RICOH CO LTD

AI summary

It is an object of the present invention to provide a toner containing an ethyl acetate-soluble polyester component and an ethyl acetate-insoluble polyester component, wherein the toner is granulated in an aqueous medium, the ethyl acetate-insoluble polyester component is obtained by elongating and/or cross-linking a modified polyester resin during granulating and/or after granulating, the modified polyester resin is produced by condensation polymerization of an acid component and at least one type of diol compound selected from aliphatic diol and alicyclic diol in the presence of a catalyst, and the mass average molecular weight of the modified polyester resin is 10,000 to 100,000.