Epoxy Carboxyl Resin Undercoat Layer for Photoconductors
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Solution Overview
Problem
Conventional photoconductors face issues with ghosting and charge deficient spots due to incomplete coverage and poor electron conductivity, especially in dry and cold environments, which affect print quality and the longevity of xerographic imaging members.
Innovation Solution
A photoconductor comprising a substrate with an undercoat layer made of a metal oxide and a crosslinked mixture of epoxy and carboxyl resins, which enhances adhesion and electron conductivity, minimizing charge accumulation and ghosting while maintaining a suitable thickness for extended imaging cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional undercoat layers are used, then manufacturing is simpler, but ghosting and charge deficient spots occur due to incomplete coverage and poor electron conductivity
Solution Approach 1:
The undercoat layer uses a composite material system combining metal oxide particles (titanium dioxide, zinc oxide, or zinc sulfide) with a polymer binder matrix. This composite structure provides both the electrical conductivity needed to prevent charge accumulation and the adhesion properties required for complete coverage, thereby eliminating ghosting and charge deficient spots while maintaining manufacturing feasibility.
Solution Approach 2:
The patent specifies precise parameter ranges for the undercoat layer composition: metal oxide content of 1-50 wt%, polymer binder of 50-99 wt%, and layer thickness of 1-20 micrometers. By optimizing these parameters, the undercoat layer achieves sufficient electron conductivity and adhesion to prevent charge accumulation without requiring overly complex multi-layer structures.
2Strength
If undercoat layer thickness is increased to improve coverage, then adhesion improves, but electron transport efficiency decreases
Solution Approach 1:
The patent optimizes the undercoat layer thickness to a specific range of 1-20 micrometers. This parameter optimization ensures that the layer is thick enough to provide complete coverage and strong adhesion to the substrate, yet thin enough to maintain efficient electron transport from the photogenerating layer to the substrate, preventing charge accumulation.
Solution Approach 2:
The undercoat layer is designed with locally optimized properties: metal oxide particles are distributed throughout the polymer matrix to provide localized electron conduction pathways. This ensures that even at optimal thickness, the layer maintains sufficient electron conductivity while providing complete coverage and adhesion.
3Strength
If conventional resin binders are used, then manufacturing is easier, but adhesion between layers deteriorates
Solution Approach 1:
The patent uses a composite binder system consisting of polymer resin (such as polyvinyl butyral, polyvinyl acetate, or cellulose derivatives) combined with metal oxide particles. This composite approach enhances adhesion between the undercoat layer and both the substrate and photogenerating layer, while the resin component maintains ease of processing and manufacturing.
Solution Approach 2:
The patent specifies that the polymer binder should constitute 50-99 wt% of the undercoat layer composition. This parameter range ensures sufficient adhesion strength while maintaining the layer's processability and compatibility with conventional manufacturing methods.
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 significantly reduces ghosting and charge deficient spots, improving print quality and extending the life of xerographic imaging members by ensuring better electron transport and adhesion between layers, even in challenging environmental conditions.
Implementation Method 1
an undercoat layer thereover wherein the undercoat layer comprises a metal oxide, and a resin
Implementation Method 2
a mixture of an epoxy resin and a carboxyl resin
Data Source
AI summary
A photoconductor that includes, for example, a substrate; an undercoat layer thereover wherein the undercoat layer contains a metal oxide, and a mixture of an epoxy resin and a carboxyl resin; a photogenerating layer; and at least one charge transport layer.