Electrophotographic Photoreceptor Undercoat Layer Ghost Reduction

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Solution Overview

Problem

Electrophotographic photoreceptors suffer from the occurrence of ghosts due to uneven distribution of metal oxide particles in the undercoat layer, leading to inhibited electric charge transfer and accumulation at the interface between the photosensitive and undercoat layers, which affects image formation in continuous imaging processes.

Innovation Solution

An electrophotographic photoreceptor with a conductive substrate, an undercoat layer containing a binder resin, metal oxide particles, and an electron-accepting anthraquinone compound, where the reflectance of the undercoat layer is adjusted between 2% to 5% for light with a wavelength of 470 nm to 510 nm to control the aggregation state of metal oxide particles, promoting even and dense distribution and reducing charge accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal oxide particles are added to the undercoat layer to improve charge transfer, then electric charge transfer is enhanced, but particle aggregation occurs leading to uneven distribution and ghost formation

Engineering Contradiction:

Improveelectric charge transferVSAvoidparticle distribution uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

An electron-accepting compound with anthraquinone structure is introduced as an intermediary substance between the metal oxide particles and the binder resin. This compound acts as a mediator that facilitates uniform dispersion of metal oxide particles in the undercoat layer, preventing aggregation while maintaining enhanced charge transfer capability. The anthraquinone compound specifically interacts with metal oxide particles to control their distribution state.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The reflectance of the undercoat layer is precisely controlled within the range of 2% to 5% for light with wavelength 470 nm to 510 nm. By adjusting this optical parameter, the aggregation state of metal oxide particles is regulated, ensuring uniform distribution. This reflectance control serves as a key parameter to maintain both charge transfer efficiency and particle distribution uniformity.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If metal oxide particles are used to enhance charge transfer, then image quality improves, but charge accumulation at the interface occurs causing ghosts in continuous imaging

Engineering Contradiction:

Improveimage qualityVSAvoidghost formation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The electron-accepting compound with anthraquinone structure serves as an intermediary that prevents charge accumulation at the interface between the photosensitive layer and undercoat layer. It facilitates smooth charge transfer across the interface, eliminating the harmful charge buildup that causes ghosts in continuous imaging processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By controlling the reflectance parameter of the undercoat layer within 2% to 5% for specific wavelengths, the aggregation state of metal oxide particles is optimized. This parameter control ensures continuous and uniform charge transfer, preventing charge accumulation that would otherwise generate ghosts during continuous image formation.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the undercoat layer reflectance is increased to control particle aggregation, then particle distribution improves, but charge transfer may be inhibited

Engineering Contradiction:

Improveparticle distributionVSAvoidcharge transfer

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The reflectance of the undercoat layer is precisely controlled within the optimal range of 2% to 5% for light with wavelength 470 nm to 510 nm. This specific parameter range simultaneously achieves two objectives: it controls the aggregation state of metal oxide particles to ensure uniform distribution, while maintaining sufficient charge transfer capability. The electron-accepting anthraquinone compound further enhances charge transfer within this reflectance range.

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 controlled reflectance and particle distribution reduce the occurrence of ghosts by enhancing electric charge transfer, resulting in improved image quality and reduced afterimage issues in continuous image formation.

Implementation Method 1

the reflectance RL of the undercoat layer for light having a wavelength ranging approximately from 470 nm to 510 nm is approximately from 2% to 5%

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

an electron-accepting compound having an anthraquinone structure... promoting even and dense distribution and reducing charge accumulation

Methodology Applied

Scientific EffectElectron transfer: Electron Beam

Data Source

PatentUS9939743B2Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Publication Date: 2018.04.10 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes a conductive substrate; an undercoat layer disposed on the conductive substrate and containing a binder resin, metal oxide particles, and an electron-accepting compound having an anthraquinone structure; and a photosensitive layer disposed on the undercoat layer, wherein the reflectance RL of the undercoat layer for light having a wavelength ranging approximately from 470 nm to 510 nm is approximately from 2% to 5%.