Charge Transfer Molecule TiO2 Undercoat Additive Ghosting

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Solution Overview

Problem

Conventional electrophotographic imaging members face issues with print quality, particularly ghosting and charge accumulation, due to the limitations of undercoat layer thickness and electron conductivity, leading to defects like charge deficient spots and bias charge roll leakage breakdown.

Innovation Solution

The incorporation of a charge transfer molecule/metal oxide complex, specifically a charge transfer molecule/TiO2 complex, into the undercoat layer to enhance electron conductivity and reduce ghosting, allowing for thicker undercoat layers without sacrificing print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the undercoat layer is made thicker to improve coverage and eliminate pin holes, then coverage quality improves, but electron transport efficiency deteriorates

Engineering Contradiction:

Improvecoverage qualityVSAvoidelectron transport efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces a charge transfer molecule into the undercoat layer formulation, changing the chemical composition parameters to enable thicker layers while maintaining electron transport. This additive modifies the electrical properties of the undercoat material, allowing thickness increases without the previously observed electron transport degradation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The undercoat layer is formulated as a composite material containing both the conventional undercoat resin and a charge transfer molecule additive. This composite structure combines the coverage benefits of thicker layers with the electron transport capabilities enabled by the charge transfer molecule, resolving the contradiction between thickness and electron transport efficiency.

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If the undercoat layer is made thinner to improve electron transport, then electron transport efficiency improves, but coverage quality deteriorates with pin holes

Engineering Contradiction:

Improveelectron transport efficiencyVSAvoidcoverage quality

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

By adding the charge transfer molecule to the undercoat formulation, the patent changes the electrical parameters of the undercoat material itself, enabling it to maintain high electron transport efficiency even at increased thicknesses that would normally cause coverage defects.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional undercoat materials are used to maintain simplicity, then manufacturing ease is maintained, but print quality deteriorates with ghosting and charge accumulation

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidprint quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The charge transfer molecule acts as an intermediary additive in the undercoat layer, mediating between the conventional undercoat materials and the substrate. It facilitates improved electron transport and charge management without requiring a complete reformulation of the undercoat system, thus maintaining manufacturing simplicity while achieving superior print quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the undercoat layer by incorporating the charge transfer molecule, which changes the electrical conductivity and charge transport characteristics. This parameter change enables elimination of ghosting and charge accumulation defects while using conventional undercoat resin systems.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If sequential images are printed to increase productivity, then output increases, but charge accumulation causes image density changes revealing previous images

Engineering Contradiction:

Improveprinting throughputVSAvoidimage density consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The charge transfer molecule in the undercoat layer serves as an intermediary that facilitates complete electron transport from the photogenerating layer to the substrate. This intermediary function prevents charge accumulation between sequential prints, ensuring consistent image density even during high-volume printing operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 charge transfer molecule/TiO2 complex effectively minimizes or eliminates ghosting and improves print quality by maintaining image density consistency and reducing residual potential, even in dry and cold environments.

Implementation Method 1

the undercoat layer comprises a charge transfer molecule/metal oxide complex

Methodology Applied

Scientific EffectCharge transfer:

Implementation Method 2

Upon exposure to light, the charge is dissipated

Methodology Applied

Scientific EffectPhotoconduction: Photoconductivity

Data Source

PatentUS7462433B2Photoreceptor additive

Publication Date: 2008.12.09 XEROX CORP

AI summary

The presently disclosed embodiments relate in general to electrophotographic imaging members, such as layered photoreceptor structures, and processes for making and using the same. More particularly, the embodiments pertain to a photoreceptor additive to improve image quality.