Electrophotographic Conductive Member for Low-Bias Fogging Suppression
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Solution Overview
Problem
The reduction of charging bias in electrophotographic image forming apparatuses leads to fogging on electrophotographic images due to potential unevenness and increased reverse fogging, which affects image quality.
Innovation Solution
An electrophotographic conductive member with a conductive layer comprising a matrix of a crosslinked first rubber and dispersed domains of a crosslinked second rubber and conductive particles, where the domains' volume resistivity is controlled to suppress discharge unevenness and ensure efficient charge transfer, with specific impedance and resistivity ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the charging bias is reduced to save energy, then energy consumption is reduced, but fogging occurs on the electrophotographic image
Solution Approach 1:
The patent changes the physical and chemical parameters of the charging member by controlling the volume resistivity of the elastic layer (1.0×10^3 to 1.0×10^8 Ω) and using specific rubber materials with controlled crosslinking. This allows the charging member to maintain uniform discharge characteristics at lower charging biases (-700V to -900V), preventing fogging while reducing energy consumption compared to conventional high bias systems
Solution Approach 2:
The patent uses composite materials consisting of specific rubber materials (e.g., NBR, SBR, EPDM) with controlled crosslinking to create an elastic layer with uniform volume resistivity. This composite structure ensures uniform charge distribution and prevents the fogging that typically occurs at low charging biases, enabling energy savings without image quality degradation
2Loss of energy
If the charging bias is reduced, then energy savings are achieved, but charge transfer uniformity deteriorates
Solution Approach 1:
The patent modifies the volume resistivity parameter of the elastic layer to a specific range (1.0×10^3 to 1.0×10^8 Ω) through material selection and crosslinking control. This parameter change ensures uniform charge transfer across the photosensitive member surface even at reduced charging biases, maintaining manufacturing precision while achieving energy savings
Solution Approach 2:
The patent ensures uniform local properties throughout the elastic layer by controlling the volume resistivity distribution. The elastic layer is designed to have consistent electrical properties at all points, which maintains uniform charge transfer characteristics across the entire charging surface when operating at lower biases
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 prevents fogging on electrophotographic images even at low charging biases, enabling high-quality image formation by stabilizing the charge transfer process.
Implementation Method 1
a conductive layer provided on the outer surface of the support... an impedance is 1.0×10³ to 1.0×10⁸ Ω when an electrode is directly provided on the outer surface of the electrophotographic conductive member and an alternating current voltage having an amplitude of 1 V and a frequency of 1.0 Hz is applied between the outer surface of the support and the electrode
Implementation Method 2
The charging member is a member that generates discharge between the charging member and an electrophotographic photosensitive member to charge a surface of the electrophotographic photosensitive member
Data Source
AI summary
An electrophotographic conductive member comprising: a conductive layer provided on an outer surface of a support, wherein the conductive layer comprises a plurality of domains dispersed in a matrix, the plurality of domains comprise a crosslinked product of a second rubber and a conductive particle, an outer surface of the electrophotographic conductive member is configured of the matrix and an exposed portion of the domain exposed on the outer surface of the electrophotographic conductive member, an impedance is 1.0×103 to 1.0×108Ω of the electrophotographic conductive member, and when specific regions are a first region and a second region, a volume resistivity R1 of a portion being not the conductive particle in the first region and a volume resistivity R2 of a portion being not the conductive particle in the second region satisfy R1>R2.