Charge Transport Layer Crazing and Cracking Prevention

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Solution Overview

Problem

Photoconductors face issues with crazing, cracking, and crystallization in the charge transport layer, which can lead to print defects and compromised electrical and mechanical performance, especially when exposed to human touch or chemicals.

Innovation Solution

Incorporating octyl/decyl glycidyl ether (OGE) and dodecyl/tetradecyl glycidyl ether (DGE) into the charge transport layer to enhance resistance to crazing, cracking, and crystallization while maintaining the electrical and mechanical properties of the photoconductor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the concentration of charge transport molecule is increased to improve charge transport performance, then charge transport efficiency is improved, but crystallization occurs resulting in increased residual discharge and image defects

Engineering Contradiction:

Improvecharge transport efficiencyVSAvoidimage quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the charge transport layer by incorporating specific plasticizers (phthalates, benzoates, or carboxylic acid esters) to modify the molecular packing and crystallization behavior of charge transport molecules, enabling high concentration loading without crystallization-induced defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite charge transport layer system combining charge transport molecules with specific plasticizer additives, where the plasticizer acts as a molecular spacer and crystallization inhibitor, allowing the composite material to achieve both high charge transport efficiency and image quality

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional additives are used to enhance crazing/cracking resistance, then surface integrity is improved, but electrical and mechanical performance is degraded

Engineering Contradiction:

Improvecrazing/cracking resistanceVSAvoidelectrical and mechanical performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent carefully controls the concentration range of plasticizer additives (0.1-10 wt%) to provide sufficient crazing/cracking resistance while maintaining electrical and mechanical performance, avoiding the degradation issues associated with higher additive concentrations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses small amounts of plasticizer additives that serve their protective function during the operational lifetime of the photoconductor, after which they can be replaced by simply replacing the charge transport layer, allowing optimization of additive concentration for performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS7955769B2Control of crazing, cracking or crystallization of a charge transport layer in a photoconductor

Publication Date: 2011.06.07 LEXMARK INTERNATIONAL INC

AI summary

Embodiments of a photoconductor for use in a printer or printer cartridge comprise an electrically conductive substrate, a charge generation layer disposed over the electrically conductive substrate, and a charge transport layer disposed over the charge generation layer, wherein the charge transport layer comprises charge transport molecules with octyl/decyl glycidyl ether (OGE) or dodecyl/tetradecyl glycidyl ether (DGE), or combinations thereof, added to improve resistance to crazing, cracking and crystallization in the change transport layer.