Electrophotographic Photoreceptor Outermost Surface Layer Composition

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Solution Overview

Problem

Electrophotographic photoreceptors face issues with density unevenness and ghosting due to charge traps in the outermost surface layer, which affect the mechanical strength and image quality over time.

Innovation Solution

A composition comprising a compound represented by formula (I) and a compound with charge transportability and an azo group is used to form the outermost surface layer, inhibiting charge trap formation and improving compatibility, thereby reducing density unevenness and ghosting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional outermost surface layer is used, then the photoreceptor can be manufactured with standard materials, but density unevenness and ghosting occur due to charge traps

Engineering Contradiction:

Improveimage quality stabilityVSAvoiddensity uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the outermost surface layer by incorporating specific compounds (compounds of formula (I) and azo group compounds) that inhibit charge trap formation. This compositional parameter change resolves the contradiction by maintaining manufacturing feasibility while eliminating density unevenness and ghosting defects.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system in the outermost surface layer combining multiple functional compounds (formula (I) compounds for charge transport and azo group compounds for charge trap inhibition). This composite approach achieves both manufacturing compatibility and superior image quality stability without density defects.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the outermost surface layer composition is optimized to prevent charge traps, then density uniformity improves, but manufacturing complexity increases

Engineering Contradiction:

Improvedensity uniformityVSAvoidmaterial composition complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent optimizes specific compositional parameters (presence of formula (I) compounds and azo group compounds) rather than completely redesigning the material system. This targeted parameter optimization achieves density uniformity while keeping the overall manufacturing process and material framework relatively simple and compatible with existing production.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a simple outermost surface layer is used, then manufacturing is easier, but mechanical strength deteriorates over time

Engineering Contradiction:

Improvesurface layer fabricationVSAvoidmechanical strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent employs a composite material formulation in the outermost surface layer that combines charge-transporting compounds with structurally robust compounds of formula (I). This composite structure provides both ease of manufacture through conventional processing and enhanced mechanical strength that resists deterioration over time.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent imparts local quality enhancement to the outermost surface layer by concentrating specific functional compounds (formula (I) and azo group compounds) in this region. This localized compositional optimization provides the surface layer with both manufacturability and superior mechanical strength without complicating the overall device structure.

Inventive Principle:

Principle #3Local quality

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 enhances the mechanical strength of the outermost surface layer and prevents density unevenness and ghosting, ensuring stable image formation over a long period.

Implementation Method 1

an outermost surface layer that is a layer made of a cured material of a composition including at least one compound represented by the following formula (I) and at least one compound having charge transportability and an azo group

Methodology Applied

Scientific EffectCuring:

Implementation Method 2

F represents an n-valent organic group having a hole transporting property

Methodology Applied

Scientific EffectHole transport:

Implementation Method 3

at least one compound having charge transportability and an azo group

Methodology Applied

Scientific EffectPhotoisomerization:

Data Source

PatentUS8283096B2Electrophotographic photoreceptor, process cartridge and image forming apparatus

Publication Date: 2012.10.09 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor comprising:a conductive substrate;a photosensitive layer formed on the conductive substrate; andan outermost surface layer that is a layer made of a cured material of a composition including at least one compound represented by the following formula (I) and at least one compound having charge transportability and an azo group:wherein in formula (I), F represents an n-valent organic group having a hole transporting property, R represents a hydrogen atom or an alkyl group, L represents a divalent organic group, n represents an integer of 1 or more, and j represents 0 or 1.