Photoreceptor Surface Protecting Layer and Cleaning Blade
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Solution Overview
Problem
Existing electrophotographic image forming systems face issues with thread-like adhesion of aggregates derived from external additives to the photoreceptor, leading to image defects, despite efforts to improve wear resistance and charge transporting properties.
Innovation Solution
The system incorporates a photoreceptor with a surface protecting layer containing a specific hole transporting compound and a cleaning blade with a tip ridge having a specific edge angle and effective contact angle, preventing thread-like adhesion while maintaining charge transporting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a surface protecting layer containing a hole transporting compound with radical polymerizable groups is used to improve wear resistance and charge transporting property, then the photoreceptor achieves longer life and higher hardness, but unreacted groups remain in the layer causing aggregates of external additives to form and adhere in a thread-like manner leading to image defects
Solution Approach 1:
The patent changes the chemical parameter by introducing a silane coupling agent that reacts with unreacted radical polymerizable groups, transforming them into silane crosslinked structures. This parameter change eliminates the harmful unreacted groups while preserving the protective function of the surface layer, thereby preventing aggregate adhesion without sacrificing wear resistance.
Solution Approach 2:
The silane coupling agent acts as an intermediary substance that bridges the hole transporting compound and the external additives. It reacts with unreacted groups to form silane crosslinked structures, mediating the interaction between the surface protecting layer and external additives, thereby preventing the formation of thread-like adhesion while maintaining charge transporting properties.
2Strength
If the surface pressure distribution of the cleaning blade is adjusted to reduce wear, then wear resistance improves, but the adjustment does not effectively reduce thread-like adhesion of aggregates
Solution Approach 1:
The silane coupling agent serves as a chemical intermediary that addresses the aggregate adhesion problem through chemical reaction rather than mechanical adjustment. It reacts with unreacted groups in the surface protecting layer to form silane crosslinked structures, providing a chemical solution that complements the mechanical wear reduction achieved through cleaning blade pressure optimization.
Solution Approach 2:
The surface protecting layer becomes a composite structure containing the hole transporting compound, polymerizable monomer, and silane coupling agent. This composite material combines the wear-resistant properties of the original surface layer with the aggregate-preventing properties of the silane crosslinked structures, achieving both wear resistance and prevention of thread-like adhesion simultaneously.
3Strength
If a curable resin composed of polyfunctional radical polymerizable monomer is used in the surface protecting layer to achieve higher hardness and wear reduction, then wear resistance improves, but aggregates of external additives are likely to be formed near unreacted groups causing image defects
Solution Approach 1:
The patent changes the chemical composition parameter by adding a silane coupling agent to the curable resin system. This parameter change enables the formation of silane crosslinked structures that eliminate unreacted radical polymerizable groups, thereby preventing aggregate formation while maintaining the hardness and wear resistance provided by the polyfunctional radical polymerizable monomer.
Solution Approach 2:
The surface protecting layer is formulated as a composite material containing the polyfunctional radical polymerizable monomer, hole transporting compound, and silane coupling agent. This composite structure combines the hardness and wear resistance of the crosslinked polymer network with the aggregate-preventing silane crosslinked structures, achieving both high hardness and prevention of thread-like adhesion.
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
This configuration effectively prevents thread-like adhesion of external additive aggregates, ensuring excellent wear resistance and good image quality by reducing unreacted groups in the surface protecting layer and optimizing the contact angle of the cleaning blade.
Implementation Method 1
wherein the surface protecting layer includes a silane coupling agent and a polymer of a hole transporting compound having a polymerizable group
Data Source
AI summary
An electrophotographic image forming system forms an electrostatic latent image on at least a photoreceptor, develops an image using an electrostatic charge image developing toner, and removes the toner using a cleaning blade. A tip ridge of the cleaning blade is pressed against a surface of the photoreceptor. The system includes a photosensitive layer of the photoreceptor and a surface protecting layer that is provided on a surface of the photosensitive layer. The surface protecting layer includes a polymerizable monomer having at least two polymerizable groups in a molecule and a polymer of a hole transporting compound having a polymerizable group represented by General formula (1). The tip ridge of the cleaning blade has an edge angle that is obtuse and less than 120° and is pressed against the surface of the photoreceptor at an effective contact angle that is in a range of 8 to 20°.