Urea-Modified Polyester Toner for Low-Temperature Fixing

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Solution Overview

Problem

Conventional toners face issues with low temperature fixing, adhesion to coated papers, and filming on triboelectricity generating parts, particularly when used on diverse recording materials like polylactic acid coated papers, due to insufficient charge relaxation and high viscosity in the melted state, leading to peeling and image quality issues.

Innovation Solution

A toner with a binder resin composed of urea-modified polyester, formed by bonding isocyanate-modified crystalline and amorphous polyester segments with an amine crosslinking agent, which provides balanced viscoelasticity and charge relaxation, ensuring strong adhesion and preventing filming on triboelectricity donating members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional binder resin is used to achieve low temperature fixing, then fixing temperature is reduced, but adhesion to coated paper is insufficient causing toner peeling

Engineering Contradiction:
Improvefixing temperatureVSAvoidadhesion strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention modifies the chemical structure of polyester resin by introducing urea bonds through reaction with isocyanate compounds. This chemical modification changes the resin's properties to achieve both low-temperature fixing capability and strong adhesion to coated papers, resolving the contradiction between fixing temperature and adhesion strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite binder resin system combining modified polyester resin with specific additives and charge controlling agents. This composite structure provides synergistic effects that enable low-temperature fixing while maintaining strong adhesion and preventing toner peeling on coated papers

Inventive Principle:
Principle #40Composite materials

2Temperature

If conventional binder resin is used to achieve low temperature fixing, then fixing temperature is reduced, but filming on triboelectricity generating parts occurs

Engineering Contradiction:
Improvefixing temperatureVSAvoidfilming
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention changes the molecular structure of the binder resin by introducing urea bonds, which modify the resin's viscosity characteristics and charge properties. This prevents the resin from forming films on triboelectricity generating parts while maintaining low-temperature fixing capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the potential harmful effect of resin viscosity at low temperatures into a beneficial property by using urea-modified polyester resin that maintains appropriate viscosity for fixing while preventing excessive adhesion to triboelectricity generating parts that causes filming

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If toner is printed on coated paper with usual toner, then printing process is simple, but toner peeling occurs due to insufficient permeation

Engineering Contradiction:
Improveprinting process simplicityVSAvoidfixing strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention modifies the binder resin parameters to achieve optimal balance between permeation ability and adhesion. The urea-modified polyester resin provides sufficient permeation into coated paper while maintaining strong fixing strength, eliminating toner peeling without complicating the printing process

Inventive Principle:
Principle #35Parameter changes

4Object-generated harmful factors

If binder resin has high viscosity in melted state to prevent filming, then filming is reduced, but low temperature fixing ability is insufficient

Engineering Contradiction:
ImprovefilmingVSAvoidfixing temperature
Core Design Contradiction:
Object-generated harmful factorsVSTemperature

Solution Approach 1:

The invention precisely controls the viscosity parameters of the binder resin by modifying the polyester structure with urea bonds. This creates a resin that maintains appropriate viscosity at low temperatures for effective fixing while preventing excessive viscosity that would cause filming on triboelectricity generating parts

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 superior low temperature fixing, enhanced adhesion to various papers, and prolonged life of triboelectricity donating members by maintaining image quality and reducing peeling, even on papers with varying moisture content.

Implementation Method 1

binder resin contains urea-modified polyester constituted by urea bonding a crystalline polyester segment and an amorphous polyester segment by an amine crosslinking agent

Methodology Applied
Scientific EffectUrea bonding: Chemical Bonding

Implementation Method 2

the low temperature fixing ability can be obtained by high melting ability of the crystalline polyester and by high viscoelasticity of the amorphous polyester

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 3

the fixing is insufficiently performed when the usual toner is printed and fixed on the coated paper... because the coating material of the coated paper is not melted to deform

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 4

the low temperature fixing ability can be obtained by high melting ability of the crystalline polyester

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentUS7709173B2Toner
Publication Date: 2010.05.04 KONICA MINOLTA BUSINESS TECH INC

AI summary

A toner comprising a binder resin and a colorant, wherein the binder resin comprises an urea modified polyester, the urea modified polyester being prepared by urea-bonding an isocyanate-modified crystalline polyester segment and an isocyanate-modified amorphous polyester using an amine crosslinking agent.