Developing Roller Conductive Resin Layer Toner Charging
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Solution Overview
Problem
Developing rollers for electrophotographic image forming apparatuses face challenges in maintaining consistent toner charging and achieving high optical density, especially in low temperature and low humidity environments, leading to issues like ghosting and inconsistent image quality.
Innovation Solution
A developing roller with a conductive resilient layer and a conductive resin layer, where the resin layer includes surface-treated metal oxides such as titanium dioxide, silica, or zinc oxide, and a stabilizer, is used to ensure consistent toner charging and high optical density. The conductive resin layer is formed by mixing surface-treated metal oxides with resins and applying it on the resilient layer, enhancing the roller's conductivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-magnetic mono-component developer is used, then the developing roller can transfer toner onto the electrostatic latent image, but the toner charging becomes inconsistent and unstable resulting in ghosting
Solution Approach 1:
The patent modifies the surface properties of the developing roller by controlling the resistivity of the resilient layer (10^3 to 10^9 Ω·cm) and the outer layer (10^2 to 10^8 Ω·cm), and by adjusting surface roughness (Rz 1-20 μm). These parameter changes enable consistent toner charging and eliminate ghosting while maintaining reliable toner transfer.
Solution Approach 2:
The developing roller employs a composite structure with a resilient layer and an outer layer, where each layer has specific compositional requirements. The resilient layer contains rubber components (nitrile butadiene rubber, epichlorohydrin rubber) while the outer layer comprises resin and metal oxide particles. This composite material approach optimizes both toner transfer reliability and charging consistency.
2Adaptability or versatility
If the developing roller operates in low temperature and low humidity environments, then the apparatus can function in various conditions, but the optical density decreases and image quality deteriorates
Solution Approach 1:
The patent specifies precise parameter ranges for the developing roller layers that maintain performance across environmental variations. The resilient layer resistivity (10^3 to 10^9 Ω·cm), outer layer resistivity (10^2 to 10^8 Ω·cm), and surface roughness (Rz 1-20 μm) are optimized to ensure consistent optical density (1.05 or higher) regardless of temperature and humidity conditions.
3Quantity of substance
If the developing roller surface is made more conductive to improve toner charging, then the charging amount increases, but the control over charging becomes more difficult
Solution Approach 1:
The patent optimizes the resistivity parameters of both the resilient layer (10^3 to 10^9 Ω·cm) and outer layer (10^2 to 10^8 Ω·cm) to achieve an optimal balance. This parameter control enables sufficient toner charging amount while maintaining stable and consistent charging, preventing both insufficient charging and charging instability.
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 results in a developing roller that maintains consistent toner charging, reduces ghosting, and achieves high optical density even in challenging environmental conditions, ensuring high-quality image production over an extended period.
Implementation Method 1
The conductive resin layer may comprises a resin and a surface-treated metal oxide
Implementation Method 2
The metal oxide may be surface-treated with a silane compound
Data Source
AI summary
The disclosure provides a developing roller for an electrophotographic image forming apparatus, and a method of manufacturing the same. The developing roller includes a shaft member and a resilient member provided on the shaft member. The resilient member includes a conductive resilient layer in contact with the shaft member and a conductive resin layer defining the outer surface of the resilient member. The conductive resin layer includes a resin and a surface-treated metal oxide. The developing roller is capable of an increased amount of toner charging while stably maintaining optical density.