Charging Member Conductive Elastic Layer Dispersion Control

Solution Overview

Problem

In electrophotographic image forming apparatuses, the formation of aggregates in conductive elastic layers of charging members leads to uneven electric resistance and charging, causing defects in image reproduction due to poor dispersion of inorganic particles.

Innovation Solution

A charging member with a conductive support and a conductive elastic layer containing rubber and inorganic particles, where the average dispersion degree of aggregates is 95% or greater and the maximum particle diameter is 200 μm or less, formed using a straining process to ensure uniform dispersion and prevent aggregation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inorganic particles are dispersed in the conductive elastic layer, then conductivity is improved, but aggregates form causing uneven electric resistance

Engineering Contradiction:

Improveuniformity of electric resistanceVSAvoiddispersion uniformity of inorganic particles

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by incorporating a straining process into the manufacturing sequence before the conductive elastic layer is formed. This straining step pre-disperses the inorganic particles uniformly throughout the rubber material, preventing aggregate formation during subsequent processing and ensuring consistent electric resistance across the charging member surface.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by controlling the physical state and mechanical properties of the rubber material during processing. By adjusting the viscosity and elasticity parameters of the rubber composition during straining and formation, the patent achieves uniform dispersion of inorganic particles while maintaining the elastic properties necessary for charging member functionality.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If aggregates of inorganic particles are formed, then manufacturing is simplified, but charging uniformity deteriorates

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidcharging uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by incorporating a straining process into the manufacturing sequence before the conductive elastic layer is formed. This straining step pre-disperses the inorganic particles uniformly throughout the rubber material, preventing aggregate formation during subsequent processing and ensuring consistent electric resistance across the charging member surface.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical kneading methods with a straining process that achieves particle dispersion through controlled mechanical stress and filtration. This substitution eliminates the need for complex multi-stage kneading while achieving superior particle distribution and charging uniformity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If conventional kneading with open rolls is used, then particle dispersion is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improveparticle dispersion qualityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical kneading methods with a straining process that achieves particle dispersion through controlled mechanical stress and filtration. This substitution eliminates the need for complex multi-stage kneading while achieving superior particle distribution and charging uniformity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the complex open roll kneading process from the manufacturing sequence, retaining only the essential straining operation that achieves particle dispersion. This extraction simplifies the overall manufacturing process while maintaining high particle distribution quality.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution prevents unevenness in charging, reducing defects in image density and simplifying the manufacturing process by eliminating the need for kneading with open rolls, thereby achieving consistent and high-quality image reproduction.

Implementation Method 1

a conductive elastic layer that is provided on an outer peripheral surface of the conductive support and includes a rubber material

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a conductive elastic layer that is provided on an outer peripheral surface of the conductive support and includes a rubber material and inorganic particles

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9095999B2Charging member, charging unit, process cartridge, image forming apparatus, and method of manufacturing charging member

Publication Date: 2015.08.04 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A charging member includes a conductive support, and a conductive elastic layer that is provided on an outer peripheral surface of the conductive support and includes a rubber material and inorganic particles, and in which an average dispersion degree of aggregates of the inorganic particles is 95% or greater and a maximum particle diameter of the aggregates of the inorganic particles is 200 μm or less.