Conductive Member Domain Segmentation for Toner Adhesion
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Solution Overview
Problem
In electrophotographic apparatuses, the conductive member used for charging in the electrophotographic process experiences contamination from toner, leading to non-uniform charging and fine line disturbances, especially when used for extended periods at high speeds in low-temperature and low-humidity environments, which affects the quality of the printed images.
Innovation Solution
A conductive member with a matrix and dispersed domains, where the matrix has a higher volume resistivity than the domains, allowing for efficient charge accumulation and distribution, reducing simultaneous charge transfer and preventing toner adhesion, is used in conjunction with a toner containing a crystalline material with specific domain structures to ensure stable and uniform discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conductive member with uniform composition is used, then the structure is simple and easy to manufacture, but toner adhesion occurs leading to non-uniform charging and fine line disturbances after extended use
Solution Approach 1:
The conductive layer is segmented into multiple domains with different volume resistivities (first domain: 10^10-10^12 Ω·cm, second domain: 10^8-10^10 Ω·cm) dispersed in a matrix (10^12-10^14 Ω·cm). This segmentation creates localized charge accumulation regions that prevent toner adhesion while maintaining overall charging uniformity, resolving the contradiction between reliability and complexity.
Solution Approach 2:
Different regions of the conductive layer are assigned different volume resistivity characteristics to perform different functions: the matrix provides overall insulation, while the dispersed domains with lower resistivity provide localized charge accumulation and discharge pathways. This local quality differentiation prevents toner adhesion at critical points while maintaining simple overall structure.
2Productivity
If the conductive member is used for extended periods at high speeds in low-temperature environments, then productivity is maintained, but toner contamination increases causing potential non-uniformities
Solution Approach 1:
The conductive layer is pre-configured with domains of different volume resistivities before operation begins. These pre-positioned domains create predetermined charge accumulation and discharge pathways that actively prevent toner adhesion from occurring in the first place, rather than attempting to clean or correct contamination after it occurs. This preliminary structural arrangement ensures charging stability even during extended high-speed operation in challenging environmental conditions.
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 prevents toner contamination of the conductive member, maintains uniform charging, and ensures high-quality image formation even at high speeds and in challenging environmental conditions by promoting electrostatic repulsive forces between the toner and the conductive member.
Implementation Method 1
the matrix has a volume resistivity R1 of larger than 1.00×10^12 Ω·cm, the domains Dt has a volume resistivity R2 of smaller than the volume resistivity R1 of the matrix
Implementation Method 2
promoting electrostatic repulsive forces between the toner and the conductive member
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 of the conductive member comprises a matrix domain structure, at least a part of the domains Dt is exposed at the conductive member outer surface, the matrix has a volume resistivity R1 of larger than 1.00×1012 Ω·cm, the domains Dt has a volume resistivity of smaller than R1, the developing device comprises the toner, domains Dc formed of the crystalline material exist in a cross section of the toner, distances between adjacent wall surfaces of the domains Dc is from 30 to 1,100 nm, and a weight-average particle diameter D4 of the toner and distances Dms between adjacent wall surfaces between the domains Dt satisfies D4≥Dms.