Conductive Layer Composition for Electrophotographic Photosensitive Member

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Solution Overview

Problem

Electrophotographic photosensitive members with a conductive layer containing titanium oxide particles coated with tin oxide doped with phosphorus, tungsten, niobium, tantalum, or fluorine experience leaks under low temperature and low humidity conditions, leading to image defects such as black dots and horizontal stripes due to excessive current flow.

Innovation Solution

Incorporating a conductive layer with a combination of titanium oxide particles coated with tin oxide doped with phosphorus, tungsten, niobium, or fluorine, and uncoated titanium oxide particles, where the uncoated titanium oxide particles are present in specific volume percentages to enhance charge flow and prevent leaks, with a binder material and surface roughening agents to improve conductivity and surface properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive layer containing titanium oxide particles coated with tin oxide doped with phosphorus, tungsten, niobium, tantalum, or fluorine is used, then the conductivity of the conductive layer is improved, but leaks occur under low temperature and low humidity conditions causing image defects

Engineering Contradiction:
Improveleak preventionVSAvoidimage defects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The conductive layer uses a composite material system consisting of titanium oxide particles coated with tin oxide doped with specific elements (phosphorus, tungsten, niobium, tantalum, or fluorine). This composite structure combines the high conductivity of tin oxide with the stability and charge storage capabilities of titanium oxide, achieving reliable performance without leaks while maintaining good conductivity for electrophotographic operation.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the conductive layer uses titanium oxide particles coated with tin oxide doped with phosphorus, tungsten, niobium, tantalum, or fluorine, then the charging properties are improved, but excessive current flows under low temperature and low humidity conditions

Engineering Contradiction:
Improvecharging stabilityVSAvoidcurrent flow control
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention optimizes specific parameters of the conductive layer including the doping elements (phosphorus, tungsten, niobium, tantalum, or fluorine), particle size distribution (average primary particle diameter of titanium oxide: 0.03-0.5 μm, coating thickness: 5-50 nm), and content ratios (tin oxide: 1-20 mass%, dopant: 0.01-5 mass% based on tin oxide). These parameter optimizations enable stable charging properties while preventing excessive current flow and leaks under varying environmental conditions.

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

The proposed solution effectively prevents leaks and maintains stable charge flow, reducing image defects and ensuring consistent image quality even under challenging environmental conditions.

Implementation Method 1

a titanium oxide particle coated with tin oxide doped with phosphorus, tungsten, niobium, tantalum, or fluorine

Methodology Applied
Scientific EffectDoping: Dopants

Implementation Method 2

a leak easily occurs in the electrophotographic photosensitive member... a portion of the electrophotographic photosensitive member locally breaks down, and an excessive current flows through the portion

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP2891015B1Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus
Publication Date: 2017.02.22 CANON KK
  • EP2891015B1 patent drawingFigure 1~2
  • EP2891015B1 patent drawingFigure 3~4
  • EP2891015B1 patent drawingFigure 5

AI summary

An electrophotographic photosensitive member in which a leak hardly occurs, and a process cartridge and electrophotographic apparatus having the same are provided. The conductive layer in the electrophotographic photosensitive member includes a binder material, a first metal oxide particle, and a second metal oxide particle. The first metal oxide particle is a titanium oxide particle coated with tin oxide doped with phosphorus, tungsten, niobium, tantalum, or fluorine, and the second metal oxide particle is an uncoated titanium oxide particle. The contents of the first and second metal oxide particles in the conductive layer is 20 to 50vol.% and 1.0 to 15vol.%, respectively based on the total volume of the conductive layer. The content of the second metal oxide particle in the conductive layer is 5.0 to 30% by volume based on the content of the first metal oxide particle in the conductive layer.