Electrophotographic Photoreceptor Undercoating Layer Conductivity Stability

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Solution Overview

Problem

Electrophotographic photoreceptors with undercoating layers containing surface-treated inorganic particles experience conductivity loss on the conductive substrate's outer peripheral surface, leading to image density unevenness due to oxide film formation, especially when the inorganic particle contact proportion exceeds 91%.

Innovation Solution

An electrophotographic photoreceptor with an undercoating layer containing surface-treated inorganic particles, where the inorganic particle contact proportion on the conductive substrate's outer peripheral surface is maintained between 82% and 91%, preventing oxide film formation and ensuring consistent conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the undercoating layer contains surface-treated inorganic particles to improve dispersibility, then the dispersibility of inorganic particles is improved, but conductivity on the outer peripheral surface of the conductive substrate decreases with time due to oxide film formation

Engineering Contradiction:

Improvedispersibility of inorganic particlesVSAvoidconductivity stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention changes the parameter of inorganic particle contact proportion on the conductive substrate from >91% to 82-91%, which prevents oxide film formation while maintaining dispersibility. This parameter optimization resolves the contradiction between improving dispersibility and maintaining conductivity stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the potentially harmful effect of inorganic particles causing oxide film formation into a beneficial configuration by controlling their contact proportion. The controlled presence of inorganic particles (82-91% contact proportion) maintains both dispersibility and conductivity stability, transforming the harmful side effect into an acceptable and stable configuration.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Stability of the object's composition

If the inorganic particle contact proportion is increased to improve dispersibility, then the dispersibility is improved, but image density unevenness occurs due to conductivity loss

Engineering Contradiction:

Improvedispersibility of inorganic particlesVSAvoidimage density uniformity

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention optimizes the inorganic particle contact proportion parameter to 82-91%, which is sufficient to ensure dispersibility but not high enough to cause oxide film formation and conductivity loss. This precise parameter control prevents image density unevenness while maintaining good dispersibility.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If surface-treated inorganic particles are used in the undercoating layer, then dispersibility is improved, but conductivity decreases with time due to oxide film formation on the conductive substrate

Engineering Contradiction:

Improvedispersibility of inorganic particlesVSAvoidconductivity duration

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The invention controls the inorganic particle contact proportion to 82-91%, which prevents oxide film formation on the conductive substrate and maintains conductivity over time. This parameter optimization ensures long-term conductivity stability while preserving the dispersibility benefits of surface-treated inorganic particles.

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 configuration prevents image density unevenness by maintaining the inorganic particle contact proportion within the specified range, ensuring stable current flow and image quality even after continuous use, with a current reduction rate of 20% or less.

Implementation Method 1

conductivity on an outer peripheral surface of the conductive substrate partially decreases with time as the photoreceptor is used, thereby causing density unevenness in an obtained image

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11079693B2Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Publication Date: 2021.08.03 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes: a conductive substrate; an undercoating layer that contains inorganic particles surface-treated with a surface treatment agent, and is provided in contact with an outer peripheral surface of the conductive substrate; and a photosensitive layer provided on the undercoating layer, wherein, with respect to the outer peripheral surface of the conductive substrate, a proportion of an area being in contact with the inorganic particles is from 82% to 91%.