Composite Toner Resin for Low-Temperature Fixing and Offset Resistance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Toner in electrophotography faces challenges in achieving low-temperature fixability while maintaining heat-resistant storage stability and hot offset resistance, as increasing printing speed leads to defective fixation and energy consumption issues, and simply controlling thermal properties of binder resins does not provide a good balance between these requirements.

Innovation Solution

A toner composition comprising a crystalline polyester resin, an amorphous resin, and a composite resin with specific molecular weight distribution and Fourier transform infrared spectroscopic characteristics, which improves low-temperature fixability, heat-resistant storage stability, and hot offset resistance by optimizing the ratio of crystalline to amorphous components and incorporating a condensation polymerization resin unit and an addition polymerization resin unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fixing temperature is increased to prevent defective fixation at high printing speeds, then the fixation quality is improved, but energy consumption increases and deterioration of fixing members accelerates

Engineering Contradiction:
Improvefixation qualityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the thermal parameters of the binder resin by selecting specific glass transition temperatures (60-90°C) and softening temperatures (90-110°C), enabling effective fixation at lower temperatures (80-100°C) while maintaining image quality and reducing energy consumption

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite binder resin systems combining polyester resins with other resin types (such as polyurethane or polyacrylic resins) to achieve a balance between low-temperature fixability and heat-resistant storage stability, allowing effective fixation without excessive temperature increase

Inventive Principle:
Principle #40Composite materials

2Temperature

If the glass transition temperature of binder resins is lowered to improve low-temperature fixability, then fixation performance is improved, but heat-resistant storage stability deteriorates

Engineering Contradiction:
Improvefixation temperatureVSAvoidheat-resistant storage stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent optimizes the glass transition temperature to a specific range (60-90°C) rather than simply lowering it, and combines this with controlling the softening temperature (90-110°C) to achieve both low-temperature fixability and adequate heat-resistant storage stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite resin systems where polyester resins are combined with other resin types having complementary thermal properties, allowing the system to exhibit low-temperature fixability while maintaining heat-resistant storage stability through the synergistic effects of the composite materials

Inventive Principle:
Principle #40Composite materials

3Temperature

If the softening temperature of binder resins is lowered to improve low-temperature fixability, then fixation performance is improved, but hot offset resistance deteriorates

Engineering Contradiction:
Improvefixation temperatureVSAvoidhot offset
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent carefully controls the softening temperature within the range of 90-110°C, which is low enough to enable effective fixation at reduced temperatures but high enough to prevent hot offset, achieving a balance between fixability and offset resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite binder resin systems that combine polyester resins with other resin types having different thermal characteristics, creating a multi-phase structure where different resin components contribute to different functions: low-temperature fixability from one component and hot offset resistance from another component

Inventive Principle:
Principle #40Composite materials

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 a good combination of low-temperature fixability, heat-resistant storage stability, and hot offset resistance, preventing filming on organic photoreceptors and maintaining image quality even under physical stresses, thus addressing the limitations of existing toner technologies.

Implementation Method 1

controlling thermal properties, such as the glass transition temperature (Tg) and the softening temperature (T1/2), of its binder resins

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

a non-olefin-based crystalline polymer binder which sharply melts at the glass transition temperature

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

a toner image is fixed on a recording medium, such as paper, by application of heat and pressure

Methodology Applied
Scientific EffectHeat application: Heating

Implementation Method 4

Fourier transform infrared spectroscopic characteristics

Methodology Applied
Scientific EffectFourier transform infrared spectroscopy: Absorption Spectroscopy

Data Source

PatentEP2648045B1Toner, image forming method, and process cartridge
Publication Date: 2015.10.14 RICOH CO LTD
  • EP2648045B1 patent drawingFigure 1
  • EP2648045B1 patent drawingFigure 2
  • EP2648045B1 patent drawingFigure 3~4

AI summary

A toner including a crystalline polyester resin (A), an amorphous resin (B), and a composite resin (C) having a condensation polymerization resin unit and an addition polymerization resin unit is provided. A molecular weight distribution of the toner based on THF-soluble contents thereof has a main peak within a molecular weight range from 1,000 to 10,000 and a half bandwidth of the main peak is 15,000 or less. The molecular weight distribution is determined by gel permeation chromatography. The toner includes chloroform-insoluble contents. A ratio C/R of the toner is within a range from 0.03 to 0.55. C and R represent heights of spectrum peaks specific to the crystalline polyester resin (A) and the amorphous resin (B), respectively, determined by a Fourier transform infrared spectroscopic attenuation total reflection method after the toner is stored in a thermostatic chamber at 45°C for 12 hours.