Electrophotographic Photoreceptor Surface Layer Elastic Deformation Control

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Solution Overview

Problem

Electrophotographic photoreceptors face issues with uneven image density and fogging due to differences in abrasion resistance across the surface, leading to problems in cleaning and image formation when repeatedly used.

Innovation Solution

An electrophotographic photoreceptor with a surface layer formed from a cured film of a composition containing a first reactive charge transport material with a hydroxyl group and a second reactive charge transport material with a methoxy group, adjusting the elastic deformation ratio within a specific range to maintain consistent abrasion resistance and reduce differences in developer amounts across the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a resin with high mechanical strength is used in the electrophotographic photoreceptor, then the life span increases, but unevenness in image density and fogging occur due to differences in abrasion resistance across the surface

Engineering Contradiction:

Improvelife spanVSAvoidimage density uniformity

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent changes the physical and chemical parameters of the surface layer by controlling the elastic deformation ratio R to be within 0.05 to 0.50, and by adjusting the glass transition temperature Tg to be 50°C or higher. These parameter changes optimize the balance between abrasion resistance and surface uniformity, resolving the contradiction between extended lifespan and image quality consistency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite material structure consisting of a surface layer containing a cured film with specific elastic deformation characteristics, combined with an underlayer. This composite structure integrates materials with different properties to achieve both high abrasion resistance for extended lifespan and uniform surface characteristics for consistent image density, preventing fogging while maintaining durability.

Inventive Principle:

Principle #40Composite materials

2Duration of action of moving object

If the surface layer has high abrasion resistance, then the photoreceptor can be used repeatedly, but differences in abrasion resistance across the surface cause unevenness in image density

Engineering Contradiction:

Improverepeated use capabilityVSAvoidimage density uniformity

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The patent precisely controls the elastic deformation ratio R within the range of 0.05 to 0.50 and sets the glass transition temperature Tg to 50°C or higher. These parameter optimizations ensure that the surface layer maintains uniform abrasion resistance across the entire surface, enabling repeated use without generating unevenness in image density or fogging.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality optimization by ensuring that the surface layer has uniform elastic deformation characteristics and glass transition temperature throughout. This localized control of material properties across the surface ensures consistent abrasion resistance, preventing areas of differential wear that would cause image density unevenness during repeated use.

Inventive Principle:

Principle #3Local quality

3Strength

If the elastic deformation ratio is increased to improve abrasion resistance, then cleaning becomes difficult, but if decreased, then image density unevenness occurs

Engineering Contradiction:

Improveabrasion resistanceVSAvoidcleaning ease

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the elastic deformation ratio R to fall within 0.05 to 0.50 and sets the glass transition temperature Tg to 50°C or higher. This precise parameter control creates an optimal balance where the surface layer has sufficient abrasion resistance for durability while maintaining appropriate elasticity that facilitates easy cleaning, preventing both image density unevenness and cleaning difficulties.

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 approach effectively suppresses unevenness in image density and fogging by ensuring consistent abrasion resistance, improving the cleaning process and image quality during repeated use.

Implementation Method 1

a surface layer that is formed of a cured film of a composition including a first reactive charge transport material having a hydroxyl group and a second reactive charge transport material having a methoxy group

Methodology Applied

Scientific EffectCondensation reaction:

Data Source

PatentUS8765341B2Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Publication Date: 2014.07.01 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes a conductive substrate, a photosensitive layer that is provided on the conductive substrate, and a surface layer that is provided on the photosensitive layer or is contained in the photosensitive layer, wherein the surface layer is formed of a cured film of a composition including a first reactive charge transport material having a hydroxyl group and a second reactive charge transport material having a methoxy group, and has an elastic deformation ratio R satisfying the following Expression (1):0.40≦R≦0.51.