Wrinkled Electrophotographic Photosensitive Member Surface for Blade Cleaning

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Solution Overview

Problem

Existing electrophotographic photosensitive members face challenges in low temperature and low humidity environments, where friction with cleaning blades is high, leading to chattering and insufficient toner removal, and transferability is poor, especially with small spherical toners.

Innovation Solution

The photosensitive member features a concavo-convex surface with exposed inorganic particles at concave portions, reducing friction and enhancing toner removal by creating a wrinkled surface with varied ridgeline directions and point contacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the surface layer is prepared as a cured layer using radically polymerized resin to increase mechanical strength, then abrasion resistance is improved, but friction force with cleaning blade increases causing chattering and insufficient cleaning

Engineering Contradiction:

Improvemechanical strength of surface layerVSAvoidfrictional force between cleaning blade and photosensitive member

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The invention applies local quality by creating a surface layer with non-uniform properties: the bulk maintains high mechanical strength from radical polymerization, while the outer surface introduces metal oxide fine particles that reduce friction. This local modification at the surface level allows simultaneous achievement of high strength and low friction without compromising either property throughout the entire layer.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite materials by combining radically polymerized resin with metal oxide fine particles in the surface layer. This composite structure leverages the high mechanical strength of the polymerized resin matrix while incorporating the low-friction characteristics of metal oxide particles at the surface, resolving the contradiction between strength and friction.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the outer surface is made very smooth by dip coating method, then manufacturing is simplified, but contact area with cleaning blade increases leading to higher friction and reduced cleanability

Engineering Contradiction:

Improveease of surface formationVSAvoidcleanability by cleaning blade

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The invention maintains the simplicity of dip coating for manufacturing while locally modifying the surface properties by incorporating metal oxide fine particles. This creates a surface with reduced friction characteristics specifically where needed for cleaning operation, without changing the overall manufacturing process complexity.

Inventive Principle:

Principle #3Local quality

3Force

If metal oxide fine particles are added to create concavo-convex shape, then friction force is reduced, but in low temperature and low humidity environment transferability becomes poor

Engineering Contradiction:

Improvefriction force with cleaning bladeVSAvoidtransferability of toner

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The invention optimizes parameters by carefully controlling the particle size, concentration, and distribution of metal oxide fine particles. By adjusting these parameters, the surface achieves sufficient concavo-convex structure for friction reduction while maintaining adequate contact areas for reliable toner transfer even in challenging 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

This design effectively reduces friction with cleaning blades and improves toner transferability by minimizing contact area and adhesion force, even in low temperature and low humidity conditions.

Implementation Method 1

the contact area between the cleaning blade and the circumferential surface of the electrophotographic photosensitive member becomes large, and an abrasion resistance between the cleaning blade and the circumferential surface of the electrophotographic photosensitive member increases

Methodology Applied

Scientific EffectFriction reduction through concavo-convex surface geometry: Friction

Implementation Method 2

a contact area between the cleaning blade and the circumferential surface of the electrophotographic photosensitive member becomes large, and an abrasion resistance between the cleaning blade and the circumferential surface of the electrophotographic photosensitive member increases

Methodology Applied

Scientific EffectAdhesion reduction through reduced contact area: Adhesive

Data Source

PatentUS12461459B2Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

Publication Date: 2025.11.04 CANON KK

AI summary

There is provided an electrophotographic photosensitive member comprising: a support, a photosensitive layer, and a surface layer in this order, wherein an outer surface of the electrophotographic photosensitive member exhibits a wrinkled shape by having a concavo-convex shape, the surface layer comprises a binder resin and an inorganic particle, and at least a part of the inorganic particle exposes at a concave portion of the concavo-convex shape.