Conductive Member Resistivity Gradient for Uniform Charging
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Solution Overview
Problem
The existing electrophotographic apparatuses face challenges in maintaining uniform charging performance and preventing contamination of the charging member, leading to image quality issues due to the migration of silica and titanium oxide fine particles, which cause discharge hindrance and potential unevenness on the electrophotographic photosensitive member.
Innovation Solution
The apparatus incorporates a conductive member with a matrix and domains, where the matrix has a volume resistivity 1.0×105 times higher than the domains, and the toner contains fine particles A and B with specific resistivity ranges, ensuring that fine particles selectively adhere to the conductive member, maintaining uniform discharge and charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica fine particles and titanium oxide fine particles are added to the toner to maintain high flowability and charging performance, then the toner exhibits stable charging performance, but the fine particles migrate from the toner and adhere to the charging member, causing discharge hindrance and non-uniform charging
Solution Approach 1:
The patent applies local quality by creating distinct regions within the charging member with different resistivity characteristics. The surface layer contains fine particles for stable charging performance, while the inner layer has different resistivity properties to prevent particle migration and facilitate uniform charge distribution, thereby addressing both the stability and contamination issues locally.
Solution Approach 2:
The patent uses composite materials by combining multiple layers with different resistivity characteristics and fine particle compositions. The charging member consists of a surface layer with silica and titanium oxide fine particles for charging stability, and an inner layer with different resistivity properties, creating a composite structure that prevents particle migration while maintaining performance.
2Productivity
If the charging member is used in high-speed process and repeated use for a long time, then productivity is improved, but member contamination occurs and charging ability is lowered due to fine particle adhesion
Solution Approach 1:
The patent applies preliminary action by pre-configuring the charging member with a multi-layer structure containing fine particles before use. This preliminary configuration ensures that the charging member maintains uniform charging performance even during high-speed operation and repeated use, preventing the degradation that would otherwise occur due to fine particle migration and contamination.
Solution Approach 2:
The patent uses parameter changes by varying the resistivity characteristics across different layers of the charging member. The surface layer has specific resistivity properties optimized for charging performance, while the inner layer has different resistivity parameters that prevent fine particle migration, allowing the system to maintain reliability under high-productivity conditions.
3Ease of manufacture
If conventional conductive member structure is used, then manufacturing is simplified, but uniform charging performance cannot be maintained due to non-uniform discharge
Solution Approach 1:
The patent applies segmentation by dividing the charging member into multiple layers with distinct resistivity characteristics and fine particle compositions. This segmented structure allows each layer to perform its specific function - the surface layer provides charging stability while the inner layer prevents particle migration - thereby achieving uniform charging performance through a systematically divided structure.
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 maintains high-quality electrophotographic images by preventing contamination and ensuring uniform charging, even in high-speed and long-term use, by selectively adhering fine particles to the conductive member, thus preventing discharge hindrance and image quality issues.
Implementation Method 1
the matrix has a volume resistivity Rm of larger than 1.00×1012 Ω·cm, the volume resistivity Rm of the matrix is 1.0×105 times or more a volume resistivity Rd of the domains
Implementation Method 2
The conductive member plays a role of transporting an electric charge from the conductive support to the surface of the conductive member and giving a charge to a contacting body by discharging
Implementation Method 3
a charging device for charging a surface of the electrophotographic photosensitive member
Implementation Method 4
a developing device for developing an electrostatic latent image formed on the surface of electrophotographic photosensitive member with a toner
Data Source
AI summary
An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device, and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, a conductive layer on the conductive member outer surface comprises a matrix and a plurality of domains dispersed in the matrix, at least some of the domains are exposed at the conductive member outer surface, the matrix has a volume resistivity of larger than 1.00×1012 Ω·cm and is 1.0×105 times or more one of the domains, the developing device comprises the toner comprising a toner particle, fine particles A and B, the fine particle A has a volume resistivity of 1.0×103 to 1.0×1010 Ω·cm, and the fine particle B is silica fine particle and having a volume resistivity of 1.0×1011 to 1.0×1017 Ω·cm.