Fluorinated Structured Organic Film Overcoat for Photoreceptor
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Solution Overview
Problem
Conventional overcoat layers in electrophotographic imaging members face challenges such as reduced electrical performance, ghosting, and light shock resistance, which affect print quality and the longevity of photoreceptors, particularly in high-speed copiers and printers.
Innovation Solution
A method of forming a fluorinated structured organic film (FSOF) overcoat layer with a cross-linking gradient, using a substrate with charge transport and charge generating layers, and incorporating a fluorinated alkyl monomer substituted with hydroxyl, carboxyl, or aldehyde functional groups, along with a leveling agent and a catalyst, to enhance mechanical and electrical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional overcoat layer is applied to protect the photoreceptor, then scratch resistance is improved, but electrical performance deteriorates and ghosting occurs
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and crosslinking density of the overcoat layer. Specifically, it uses fluorinated structured organic films with controlled crosslinking gradients to alter the physical and chemical properties of the coating, achieving both mechanical protection and electrical performance without ghosting defects
Solution Approach 2:
The patent employs composite materials by combining fluorinated monomers with specific functional groups (hydroxyl, carboxyl, or aldehyde) to create a multi-component overcoat system. This composite structure provides enhanced scratch resistance while maintaining charge transport properties through the synergistic interaction of different molecular components
2Duration of action of stationary object
If the overcoat layer is made more robust to extend photoreceptor life, then wear rate is reduced, but print quality deteriorates due to ghosting and background shading
Solution Approach 1:
The patent applies local quality by creating a crosslinking gradient within the overcoat layer. The crosslinking density varies through the thickness of the coating, with higher crosslinking near the photoreceptor surface for protection and lower crosslinking at the outer surface for optimal electrical performance and print quality
Solution Approach 2:
The patent modifies parameters by controlling the concentration and distribution of fluorinated monomers with different functional groups to achieve the desired balance between durability and print quality, eliminating ghosting while extending photoreceptor life
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 FSOF overcoat layer improves scratch resistance, reduces wear rate, and maintains electrical performance, thereby extending the life of photoreceptors and enhancing print quality by minimizing ghosting and background shading.
Implementation Method 1
The overcoat composition is cured to form an overcoat layer that is a fluorinated structured organic film, the curing comprising treating an outer surface of the overcoat composition with at least one cross-linking process
Implementation Method 2
the overcoat composition comprising a charge transport molecule
Data Source
AI summary
A method of forming an overcoat layer. The method comprises providing a substrate having an imaging structure formed thereon, the imaging structure comprising (i) a charge transport layer and a charge generating layer, or (ii) an imaging layer comprising both charge generating material and charge transport material. An overcoat composition is deposited on the imaging structure, the overcoat composition comprising a charge transport molecule, a fluorinated building block, a leveling agent, a liquid carrier and optionally a first catalyst. The fluorinated building block is a fluorinated alkyl monomer substituted at the α and ω positions with a hydroxyl, carboxyl, carbonyl or aldehyde functional group or the anhydrides of any of those functional groups. The overcoat composition is cured to form an overcoat layer that is a fluorinated structured organic film, the curing comprising treating an outer surface of the overcoat composition with at least one cross-linking process. The crosslinking process forms a cross-linking gradient in the overcoat layer. If the overcoat composition comprises the first catalyst, there is an insufficient amount of the first catalyst to fully cross-link the overcoat layer.