Ether Thiophosphate Charge Transport Layer Wear Resistance
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Solution Overview
Problem
Existing photoconductive imaging members face challenges with wear resistance, image ghosting, and residual potential issues, leading to undesirable print failures and reduced imaging cycle longevity.
Innovation Solution
The development of layered imaging members with a substrate, photogenerating layer, and charge transport layers containing specific ethers and thiophosphates, which enhance scratch resistance, electrical properties, and stability, thereby preventing residual potential cycle up and improving imaging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional photoconductive imaging members are used, then imaging function is maintained, but wear resistance is poor and scratches occur on the surface layer
Solution Approach 1:
The patent applies composite materials by combining a charge transport layer with a overcoating layer having different material properties. The overcoating layer is specifically designed with higher hardness and wear resistance than the charge transport layer, creating a composite structure where each layer performs its specialized function - the charge transport layer maintains electrical function while the overcoating layer provides mechanical protection against scratches and wear.
Solution Approach 2:
The patent uses a thin film overcoating layer (5-20 micrometers thick) that flexes with the underlying charge transport layer during imaging operations. This thin protective film acts as a sacrificial barrier that absorbs wear and scratches, protecting the more critical charge transport layer while maintaining the flexibility needed for drum rotation and imaging cycle operations.
2Productivity
If imaging members operate through multiple imaging cycles, then productivity increases, but residual potential accumulates causing image ghosting
Solution Approach 1:
The patent changes the electrical parameters of the imaging member by incorporating specific charge transport materials and hole blocking layer compositions that optimize charge carrier mobility and trapping characteristics. These parameter changes enable more complete charge dissipation between imaging cycles, preventing residual potential accumulation and the resulting image ghosting, thereby maintaining image quality over extended imaging cycle longevity.
3Strength
If charge transport layers are made more durable, then wear resistance improves, but electrical properties may deteriorate
Solution Approach 1:
The patent segments the imaging member into functionally distinct layers: a charge transport layer optimized for electrical properties and a separate overcoating layer optimized for mechanical durability and scratch resistance. This segmentation allows each layer to be independently optimized - the charge transport layer maintains excellent electrical stability for charge injection and transport, while the overcoating layer provides enhanced scratch resistance without compromising the electrical function of the underlying layer.
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 incorporation of ethers and thiophosphates in the charge transport layers results in improved wear resistance, reduced image ghosting, stable electrical properties, and extended imaging cycle life, ensuring high-quality prints with minimal scratches and residual potential issues.
Implementation Method 1
photoconductive imaging members face challenges with wear resistance, image ghosting, and residual potential issues
Data Source
AI summary
An imaging member containing an optional supporting substrate, a photogenerating layer, and at least one charge transport layer of at least one charge transport component, at least one C-ether of the formulawherein R1, R2, R3 and R4 are independently selected from the group consisting of hydrogen, alkyl, aryl, alkoxy, substituted alkyl, substituted aryl, substituted alkoxy, and halogen, and the sum of n plus m (n+m) is from about 1 to about 10, and a thiophosphate.