Lithium Carrier Core Particles for Electrophotographic Developer

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Solution Overview

Problem

Carrier core particles for electrophotographic developers exhibit significant property changes under varying environmental conditions, such as temperature and humidity, leading to inconsistent image quality due to large resistance differences and potential loss of coating resin during agitation.

Innovation Solution

Incorporating lithium into the core composition of carrier core particles and treating them with a hydroxyl-group-containing solvent to reduce lithium leaching, thereby stabilizing electrical characteristics and resistance across different humidity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium is incorporated into the core composition of carrier core particles, then electrical characteristics are improved, but lithium leaching occurs causing resistance fluctuations under varying humidity conditions

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidresistance fluctuations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A coating layer is introduced as an intermediary between the lithium-containing core particles and the external environment. This coating layer prevents direct contact between moisture and lithium, thereby suppressing lithium leaching and resistance fluctuations while preserving the electrical characteristics provided by lithium in the core composition.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin film coating is applied to the surface of carrier core particles containing lithium in their core composition. This coating film acts as a barrier that prevents moisture penetration and lithium leaching, thereby stabilizing resistance under varying humidity conditions while maintaining the electrical properties contributed by lithium.

Inventive Principle:

Principle #30Flexible shells and thin films

2Productivity

If carrier core particles are used in electrophotographic developer, then image formation is enabled, but property changes occur under varying environmental conditions leading to inconsistent image quality

Engineering Contradiction:

Improveimage formationVSAvoidproperty changes

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

A coating film is applied to carrier core particles to create a protective barrier that isolates the core material from environmental variations. This coating stabilizes the physical and chemical properties of carrier particles, ensuring consistent image quality across different temperature and humidity conditions while maintaining effective image formation capability.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The physical and chemical parameters of carrier core particles are controlled and stabilized through coating treatment. By modifying the surface parameters and protecting the core composition, the particles maintain stable properties under varying environmental conditions, enabling consistent image formation performance.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If coating resin is applied to carrier core particles, then insulation properties are improved, but coating resin loss occurs during agitation

Engineering Contradiction:

Improveinsulation propertiesVSAvoidcoating resin loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

A composite structure is created with a core composition providing electrical properties and a coating layer providing insulation. This composite design optimizes both functions while reducing coating material requirements and loss during agitation, as the coating layer is applied more efficiently and adheres better to the treated core surface.

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 method results in carrier core particles with improved electrical characteristics and reduced environmental dependency, maintaining consistent performance across diverse conditions and preventing resistance fluctuations, thus ensuring high-quality image formation.

Implementation Method 1

carrier core particles containing lithium as a core composition... have good electrical characteristics

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

treating them with a hydroxyl-group-containing solvent to reduce lithium leaching

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 3

treating them with a hydroxyl-group-containing solvent to reduce lithium leaching

Methodology Applied

Scientific EffectExtraction: Liquid-Liquid Extraction

Implementation Method 4

The magnetic force of the magnet roller forms a straight-chain like magnetic brush of carrier particles

Methodology Applied

Scientific EffectMagnetic force: Magnetic Field

Implementation Method 5

Agitation produces triboelectric charges that bond a plurality of toner particles to the carrier particles

Methodology Applied

Scientific EffectTriboelectric effect: Triboelectric Effect

Data Source

PatentEP2530528B1Carrier core material for electrophotographic developer, process for producing same, carrier for electrophotographic developer, and electrophotographic developer

Publication Date: 2017.04.05 DOWA ELECTRONICS MATERIALS CO LTD

AI summary

The carrier core particles 11 for electrophotographic developer contain lithium as a core composition. When the carrier core particles 11 are immersed in pure water at a weight ratio of 1 part core particles 11 to 10 parts pure water and shaken, the amount of lithium that leaches out to the pure water is 0.10 ppm or lower.