Developer Carrying Surface Layer for Toner Adhesion and Charge-Up Balance
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the charge-up phenomenon on developer carrying members leads to non-uniform toner charging, resulting in reduced image quality due to excessive toner adhesion and charge accumulation.
Innovation Solution
A developer carrying member with a surface layer containing a binder resin and electroconductive particles, where the electroconductive particles are distributed between 1% and 25% in a 150 nm depth range from the surface, and the surface layer has a volume resistivity of 1.0×10−2 Ω·cm to 1.0×102 Ω·cm, optimizing both toner adhesion and charge management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developer carrying member surface is made highly electroconductive to prevent charge-up, then charge uniformity improves, but toner adhesion increases excessively
Solution Approach 1:
The surface layer is designed with non-uniform electroconductive particle distribution, creating different local properties: the region from surface to 150 nm depth contains 1-25% electroconductive particles to provide moderate conductivity and reduce toner adhesion, while deeper regions have higher particle content to ensure overall charge uniformity. This local quality variation resolves the contradiction between preventing charge-up and controlling toner adhesion.
Solution Approach 2:
The patent optimizes the volume resistivity parameter of the surface layer to a specific range (1.0×10−2 Ω·cm to 1.0×102 Ω·cm) and controls the electroconductive particle content gradient through depth. By changing these parameters from uniform to gradient distribution, the surface provides moderate conductivity that prevents excessive toner adhesion while maintaining sufficient charge uniformity across the developer carrying member.
2Reliability
If the surface layer has high electroconductive particle content to reduce charge-up phenomenon, then charge uniformity improves, but toner reflection force increases causing poor image quality
Solution Approach 1:
The surface layer implements local quality variation by concentrating electroconductive particles in the deeper region (below 150 nm depth) rather than uniformly distributing them throughout. This creates a gradient structure where the immediate surface has lower particle content (1-25% in the 0-150 nm region), reducing toner reflection force and improving image quality, while the deeper high-concentration region maintains overall charge uniformity.
Solution Approach 2:
The patent transitions from considering only surface-level properties to a three-dimensional gradient structure. By controlling electroconductive particle distribution through the depth dimension (0-150 nm vs. deeper regions), the invention achieves both reduced toner reflection at the surface and sufficient charge uniformity in the bulk, resolving the contradiction through dimensional extension.
3Reliability
If the surface layer volume resistivity is lowered to prevent charge accumulation, then charge-up phenomenon reduces, but toner adhesion becomes excessive
Solution Approach 1:
The patent optimizes the volume resistivity parameter to a specific range (1.0×10−2 Ω·cm to 1.0×102 Ω·cm) that balances charge management and toner adhesion. This parameter optimization, combined with the electroconductive particle gradient distribution, ensures the surface layer has sufficient conductivity to prevent charge-up while maintaining appropriate toner reflection properties for high-quality image formation.
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 reduces toner adhesion and charge-up, ensuring stable and high-quality electrophotographic image formation by balancing toner reflection force and charge optimization.
Implementation Method 1
the surface layer contains a binder resin and electroconductive particles, and a content of the electroconductive particles in a region from a surface of the surface layer opposite to an outer surface thereof on a side facing the electroconductive support to a depth of 150 nm is 1% or more and 25% or less
Implementation Method 2
the surface layer has a volume resistivity of 1.0×10−2 Ω·cm or more and 1.0×102Ω·cm or less... balancing toner reflection force and charge optimization
Data Source
AI summary
Provided is a developer carrying member that can stably form a high-quality electrophotographic image. The developer carrying member includes an electroconductive support and a surface layer in the stated order, wherein the surface layer contains a binder resin and electroconductive particles, and a content of the electroconductive particles in a region from a surface of the surface layer opposite to an outer surface thereof on a side facing the electroconductive support to a depth of 150 nm is 1% or more and 25% or less, and wherein the surface layer has a volume resistivity of 1.0×10−2 Ω·cm or more and 1.0×102Ω·cm or less.