Multilayer Electrophotographic Photoconductor Light Absorption Control

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Solution Overview

Problem

Multilayer type electrophotographic photoconductors face issues with charge accumulation leading to image characteristic deterioration, exposure memory, and photo memory due to inadequate charge transporting ability and excessive sensitivity to light sources.

Innovation Solution

A multilayer electrophotographic photoconductor with a charge generating layer and a charge transporting layer, where the light absorption degree at 680 nm is limited to 0.8 or less and at 450 nm is 1.0 or more, to control charge generation and prevent residual charge accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the charge generating layer contains charge generating agents and the charge transporting layer contains charge transporting agents in a multilayer configuration, then the design flexibility and function control are improved, but the charge transporting ability in the charge generating layer is lowered leading to charge accumulation

Engineering Contradiction:

Improvedesign flexibilityVSAvoidcharge transporting ability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by giving different functional characteristics to different layers: the charge generating layer is optimized for charge generation with specific light absorption properties, while the charge transporting layer is optimized for charge transport. This layer-specific functional differentiation resolves the contradiction by ensuring each layer performs its designated function effectively without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining organic charge generating agents with organic charge transporting agents in a multilayer structure. This composite approach allows the system to achieve both design flexibility (through material selection) and reliable charge transport (through synergistic material combinations that maintain adequate transporting ability in the charge generating layer).

Inventive Principle:

Principle #40Composite materials

2Productivity

If the photoconductor material is made highly sensitive to the exposure light source, then the image formation efficiency is improved, but excessive charge generation occurs leading to exposure memory

Engineering Contradiction:

Improveimage formation efficiencyVSAvoidexposure memory

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by carefully controlling the light absorption degree of the photoconductive layer at specific wavelengths (680 nm and 450 nm). By adjusting these optical parameters, the patent achieves optimal sensitivity for efficient image formation while preventing excessive charge generation that would cause exposure memory, thus resolving the contradiction between productivity and harmful effects.

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 configuration stabilizes charge characteristics, reducing exposure and photo memory, and maintains high image quality over time by limiting excessive charge generation and abnormal charge accumulation.

Implementation Method 1

the light absorption degree at a 680 nm wavelength light beam in the photoconductive layer is of a value of 0.8 or less, and the light absorption degree at a 450 nm wavelength light beam is of a value of 1.0 or more

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a charge generating layer containing at least a charge generating agent

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

a charge transporting layer containing at least a charge transporting agent and a binder resin

Methodology Applied

Scientific EffectCharge transport: Conduction (electrical)

Data Source

PatentUS8765337B2Multilayer type electrophotographic photoconductor and image forming apparatus

Publication Date: 2014.07.01 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

The present invention is to provide a multilayer type electrophotographic photoconductor capable of stably obtaining a high image quality image over a long term by restraining the exposure memory and the photo memory, and an image forming apparatus comprising such a multilayer type electrophotographic photoconductor. A multilayer type electrophotographic photoconductor comprising a charge generating layer containing at least a charge generating agent on a base member directly or via an intermediate layer, and a charge transporting layer containing at least a charge transporting agent and a binder resin formed successively, wherein the light absorption degree at a 680 nm wavelength light beam in the photoconductive layer of the multilayer type electrophotographic photoconductor is of a value of 0.8 or less, and the light absorption degree at a 450 nm wavelength light beam is of a value of 1.0 or more, and an image forming apparatus comprising such a multilayer type electrophotographic photoconductor are provided.