Electrophotographic Photoreceptor Outermost Surface Layer Residual Potential

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Solution Overview

Problem

Electrophotographic photoreceptors face issues with residual potential and air bubbles in the outermost surface layer due to the low dielectric constant and poor dispersibility of fluorine-containing resin particles, which affect chargeability and wear resistance.

Innovation Solution

Incorporating fluorine-containing graft polymers as dispersing agents and defoaming agents into the outermost surface layer, adjusting the concentration of fluorine-containing resin particles and graft polymers, and optimizing the contact angle of pure water to improve dispersibility and reduce air bubbles, thereby lowering residual potential and air bubbles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fluorine-containing resin particles are used in the outermost surface layer, then wear resistance is improved, but residual potential increases due to low dielectric constant

Engineering Contradiction:

Improvewear resistanceVSAvoidresidual potential

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent combines fluorine-containing resin particles with fluorine-containing graft polymers to create a composite outermost surface layer. This composite structure allows the fluorine-containing resin particles to provide wear resistance while the fluorine-containing graft polymer with higher dielectric constant compensates for the low dielectric constant of the resin particles, thereby reducing residual potential.

Inventive Principle:

Principle #40Composite materials

2Strength

If fluorine-containing resin particles are added to improve wear resistance, then surface durability increases, but air bubbles form in the outermost surface layer

Engineering Contradiction:

Improvesurface durabilityVSAvoidair bubbles

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The fluorine-containing graft polymer acts as a dispersing agent and intermediary between the fluorine-containing resin particles and the binder resin. It improves the dispersibility of the resin particles in the coating solution, preventing aggregation and the formation of air bubbles during the coating process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If fluorine-containing resin particles with high carboxy group content are used, then dispersibility improves, but dielectric constant decreases increasing residual potential

Engineering Contradiction:

ImprovedispersibilityVSAvoidresidual potential

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent controls the carboxy group content of fluorine-containing resin particles within a specific range (30 to 300 per 10^6 carbon atoms) and adjusts the ratio of fluorine-containing graft polymer to fluorine-containing resin particles (0.1 to 10 mass%). This parameter optimization balances dispersibility improvement with maintaining adequate dielectric constant to reduce residual potential.

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 solution effectively reduces residual potential and air bubbles in the outermost surface layer, enhancing chargeability and wear resistance while maintaining a suitable dielectric constant.

Implementation Method 1

Incorporating fluorine-containing graft polymers as dispersing agents into the outermost surface layer, adjusting the concentration of fluorine-containing resin particles and graft polymers, and optimizing the contact angle of pure water to improve dispersibility

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

The outermost surface layer has a dielectric constant of 3.75 or more and 3.90 or less, effectively reduces residual potential

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 3

optimizing the contact angle of pure water to improve dispersibility and reduce air bubbles, thereby lowering residual potential and air bubbles

Methodology Applied

Scientific EffectContact angle: Surface Tension

Data Source

PatentUS11435674B2Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Publication Date: 2022.09.06 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer on the conductive substrate. The electrophotographic photoreceptor has an outermost surface layer that contains fluorine-containing resin particles and a fluorine-containing graft polymer. The fluorine-containing resin particles contain 0 or more and 30 or less carboxy groups per 106 carbon atoms. The outermost surface layer has a dielectric constant of 3.75 or more and 3.90 or less. The contact angle of pure water on the outermost surface layer is 90° or more.