Bimodal Release Agent Toner for Image Density and Releasability

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Solution Overview

Problem

Electrostatic image developing toners with small release-agent domain diameters improve image releasability but lead to decreased image density in low-temperature and low-humidity environments due to toner particle breakage during continuous image formation.

Innovation Solution

The development of an electrostatic image developing toner with a specific distribution of release-agent domain diameters, including both small-diameter and large-diameter domains, where the area fraction Sa/St is 2% or more and Sb/St is 20% or more, to enhance image releasability and prevent toner particle breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If release agent domains with small long diameters are used in toner particles, then releasability of the fixed image is improved, but image density decreases in low-temperature and low-humidity environments

Engineering Contradiction:

Improvereleasability of the fixed imageVSAvoidimage density

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The release agent domains are segmented into two distinct size groups: small domains (10-500 nm) that migrate to the toner particle surface to improve releasability, and large domains (1500-3000 nm) that remain embedded to prevent particle breakage and maintain image density during continuous image formation in low-temperature and low-humidity environments

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the toner particle are赋予 different functions through the bimodal domain distribution: the surface region contains small release agent domains for optimal releasability, while the interior region contains large release agent domains for structural cushioning and breakage prevention

Inventive Principle:

Principle #3Local quality

2Ease of operation

If release agent domains with small long diameters are used in toner particles, then releasability of the fixed image is improved, but toner particle breakage occurs during continuous image formation

Engineering Contradiction:

Improvereleasability of the fixed imageVSAvoidtoner particle strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

Large release agent domains (1500-3000 nm) are embedded within the toner particle interior before the toner is used, creating a cushioning effect that absorbs stress and prevents particle breakage during continuous image formation, particularly in low-temperature and low-humidity environments where particles are more prone to breakage

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 both improved releasability of the fixed image and suppression of image density decrease in low-temperature and low-humidity environments by using the small-diameter domains for exudation and large-diameter domains as a cushioning material during image formation.

Implementation Method 1

using the small-diameter domains for exudation

Methodology Applied

Scientific EffectExudation:

Implementation Method 2

using large-diameter domains as a cushioning material during image formation

Methodology Applied

Scientific EffectCushioning:

Data Source

PatentUS20230098900A1Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Publication Date: 2023.03.30 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrostatic image developing toner includes toner particles containing a binder resin and a release agent. In sections of the toner particles in which the sections of the toner particles have an area St in total and, among sections of domains of the release agent, sections of domains having long diameters of 10 nm or more and 500 nm or less have a total area Sa and sections of domains having long diameters of 1500 nm or more and 3000 nm or less have a total area Sb, an area fraction Sa/St is 2% or more and an area fraction Sb/St is 20% or more.