Electrostatic Toner Particle Morphology for Thick-Paper Transfer

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Solution Overview

Problem

Existing electrostatic charge image developing toners face challenges in transferring images to thick paper in high-temperature and high-humidity environments due to charge leakage and non-electrostatic adhesion forces, leading to decreased transfer efficiency.

Innovation Solution

The toner particles are designed with a specific number-average particle size of 5 μm to 8 μm and a controlled proportion of deformed particles, with circularity of 0.96 or less, ranging from 10% to 40% for small-sized particles and 10% to 30% for large-sized particles, to minimize charge leakage and reduce non-electrostatic adhesion forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the proportion of deformed particles (circularity ≤0.96) among small-sized particles is less than 10% or more than 40%, then the toner structure is more uniform, but charge leakage occurs in high-temperature and high-humidity environments

Engineering Contradiction:

Improvetransferability to thick paperVSAvoidcharge leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the particle morphology parameters by controlling the proportion of deformed particles (circularity ≤0.96) among small-sized particles to be 10-40%. This parameter optimization prevents charge leakage paths from forming between closely packed spherical particles, thereby improving transferability to thick paper in high-temperature and high-humidity environments

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional toner particles are used without controlled circularity distribution, then manufacturing is simpler, but non-electrostatic adhesion forces decrease transfer efficiency

Engineering Contradiction:

Improvetransfer efficiencyVSAvoidnon-electrostatic adhesion forces

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention optimizes the circularity parameter distribution of toner particles, specifically controlling that 10-40% of small-sized particles (4.5 μm or less) have circularity ≤0.96. This morphological parameter change reduces non-electrostatic adhesion forces between particles, thereby improving transfer efficiency without compromising manufacturing feasibility

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

This design enhances the transferability of toner images to thick paper in high-temperature and high-humidity conditions by reducing charge leakage paths and minimizing non-electrostatic adhesion forces, thereby improving transfer efficiency.

Implementation Method 1

electrostatic charge image developing toner

Methodology Applied

Scientific EffectElectrostatic charge: Electrostatics

Data Source

PatentUS20250284219A1Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Publication Date: 2025.09.11 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrostatic charge image developing toner contains toner particles, in which a number-average particle size of the electrostatic charge image developing toner is 5 μm or more and 8 μm or less, and an existence proportion of particles having a circularity of 0.96 or less among particles of the electrostatic charge image developing toner having a particle size of 4.5 μm or less is 10% by number or more and 40% by number or less.