Electrophotographic Photosensitive Member Protective Layer

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Solution Overview

Problem

Electrophotographic photosensitive members exhibit significant potential fluctuations due to environmental changes, particularly between high-temperature high-humidity and low-temperature low-humidity environments, leading to inconsistent image density and mechanical durability issues.

Innovation Solution

The development of an electrophotographic photosensitive member with a protective layer containing a polymer composition that includes a hole transporting compound with multiple (meth)acryloyloxy groups and a compound with a fluorene structure, which enhances hydrophobicity and reduces water permeation, thereby stabilizing the potential fluctuation across varying environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional protective layer compositions are used, then mechanical durability is improved, but environmental fluctuation in potential increases

Engineering Contradiction:

Improvemechanical durabilityVSAvoidenvironmental fluctuation in potential

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the protective layer by incorporating specific compounds (formula 1 with fluorene structure and hydroxy group, formula 2 with triarylamine structure) to achieve both mechanical durability and environmental stability. This resolves the contradiction by optimizing the molecular structure and functional groups of the protective layer materials.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The protective layer uses a composite material system combining multiple components: compound of formula (1), compound of formula (2), and compounds of formulas (3)-(6). This composite approach allows simultaneous achievement of mechanical durability (through crosslinking and molecular structure) and environmental potential stability (through hydrophobicity and water permeation resistance).

Inventive Principle:

Principle #40Composite materials

2Reliability

If the protective layer is made more hydrophobic to reduce water permeation, then environmental fluctuation is suppressed, but mechanical durability may be compromised

Engineering Contradiction:

Improveenvironmental fluctuation suppressionVSAvoidmechanical durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The protective layer exhibits local quality differentiation through specific functional groups: the fluorene structure (formula 1) provides hydrophobicity and water permeation resistance, while the triarylamine structure (formula 2) contributes to charge transport and mechanical properties. This localized functional distribution resolves the contradiction between hydrophobicity and mechanical durability.

Inventive Principle:

Principle #3Local quality

3Reliability

If image density consistency is improved across environments, then reliability increases, but this requires complex protective layer composition

Engineering Contradiction:

Improveimage density consistencyVSAvoidprotective layer composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective layer compounds perform multiple functions simultaneously: compound (1) provides hydrophobicity and structural stability, compound (2) enables charge transport, and compounds (3)-(6) contribute to crosslinking and mechanical strength. This multi-functionality achieves image density consistency without excessive compositional complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution effectively suppresses environmental fluctuations in potential and improves wear resistance, ensuring consistent image density and mechanical durability across different use environments.

Implementation Method 1

a polymer of a composition containing a hole transporting compound having two or more (meth)acryloyloxy groups

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a compound represented by formula (1) wherein the compound has a fluorene structure and contributes to hydrophobicity and reduced water permeation

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentUS11237494B2Electrophotographic photosensitive member, process cartridge and electrophotographic image forming apparatus

Publication Date: 2022.02.01 CANON KK

AI summary

There is provided an electrophotographic photosensitive member capable of suppressing the environmental fluctuation in repeated use. A protective layer of the electrophotographic photosensitive member contains a polymer of a composition containing a hole transporting compound having two or more (meth)acryloyloxy groups and a compound having a specific structure.