Toner Release Agent Spatial Distribution for Offset and Strength

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Solution Overview

Problem

Existing toners face challenges in achieving effective offset resistance, charging stability, and particle durability while maintaining high-quality image formation, particularly under high-temperature, high-humidity conditions, due to issues with release agent distribution and particle hardness.

Innovation Solution

A toner with a release agent of acicular or filiform shape and high aspect ratio, dispersed and encapsulated within the toner particles, is developed, allowing for controlled exudation during fixing, enhancing offset resistance and charging stability, and incorporating a metal compound of aromatic carboxylic acid to improve particle hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If release agents are positioned near the surface of toner particles to promote exposure during fixing, then offset resistance is improved, but toner particle strength decreases making particles likely to be crushed during stirring and storage

Engineering Contradiction:
ImproveoffsetVSAvoidtoner particle strength
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by creating a specific spatial distribution of release agents within toner particles. Release agents are positioned in the internal region rather than uniformly distributed or concentrated at the surface. This localized positioning in the internal region allows the particle interior to provide mechanical support while release agents remain available for offset prevention during fixing, thus resolving the contradiction between offset resistance and particle strength.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If release agents are exposed to the surface of toner particles, then offset resistance is improved, but chargeability becomes insufficient under high-temperature, high-humidity conditions

Engineering Contradiction:
ImproveoffsetVSAvoidchargeability stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent implements local quality by creating a spatially differentiated structure where release agents are concentrated in the internal region of toner particles rather than exposed at the surface. This localized internal positioning ensures that the toner surface maintains its chargeability properties even under high-temperature, high-humidity conditions, while release agents remain available within the particle to prevent offset during fixing.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If larger amounts of release agents are added to make domains larger for offset resistance, then offset resistance is improved, but overall strength of toner decreases making toner likely to be crushed

Engineering Contradiction:
ImproveoffsetVSAvoidtoner overall strength
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by confining release agents to the internal region of toner particles with controlled concentration. This localized positioning allows sufficient release agent content to be present for offset prevention while the surrounding toner matrix maintains structural integrity. The internal region acts as a reservoir that provides offset protection without compromising the overall particle strength.

Inventive Principle:
Principle #3Local quality

4Ease of operation

If toner passes under a blade configured to regulate thickness in non-magnetic one-component development, then image formation is achieved, but toner is crushed and adheres under excessive load

Engineering Contradiction:
Improveimage formationVSAvoidtoner stress resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent implements local quality by creating a concentrated release agent region in the internal part of toner particles. This internal concentration provides mechanical reinforcement that enhances stress resistance during blade regulation in non-magnetic one-component development. The release agents in the internal region act as a structural support network that prevents particle crushing and adhesion under excessive blade load while allowing proper image formation.

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 toner achieves excellent offset resistance, charging stability, and stress resistance, ensuring high-quality, long-term image accuracy and durability by effectively managing release agent distribution and particle hardness.

Implementation Method 1

The release agents quickly melt and get exposed to the surfaces of the toner particles when the toners pass under a heated roll or belt member in the contact-heating fixing methods

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

a liquid droplet solidifying step of solidifying the liquid droplets to form toner particles

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3260918B1Toner, toner-housing unit, and image-forming apparatus
Publication Date: 2019.04.03 RICOH CO LTD
  • EP3260918B1 patent drawingFigure 1~2A
  • EP3260918B1 patent drawingFigure 2B~3
  • EP3260918B1 patent drawingFigure 4~5

AI summary

Provided is a toner including at least: a binder resin; and a release agent, wherein in a transmission electron microscopic (TEM) image of a torn cross-section of the toner, the release agent has an acicular or filiform shape and an average aspect ratio of 31 or greater, and wherein a displacement amount of the toner when 250 micronewtons is applied to the toner in a microcompression test is 700 nm or less.