Charging Member Impedance Control for Color Streak Suppression
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Solution Overview
Problem
Existing electrophotographic image forming systems experience color streaks due to variations in discharge voltage and omission, which are not effectively addressed by conventional charging members in contact charging systems.
Innovation Solution
A charging member with a conductive substrate, elastic layer, and surface layer, optimized for a direct-current contact charging system, featuring specific impedance and resistance characteristics, and surface roughness to suppress color streaks by ensuring consistent voltage distribution and followability during discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional charging member is used in a DC contact charging system, then the structure is simple, but color streaks occur due to voltage distribution variations and discharge omission
Solution Approach 1:
The patent applies parameter changes by optimizing the resistance component R and impedance Z within specific ranges (R: 4.0×10^4 Ω or more and 1.0×10^6 Ω or less, Z: over 3.6×10^4 Ω and 3.5×10^5 Ω or less) to achieve consistent voltage distribution and suppress color streaks. This resolves the contradiction by tuning electrical parameters to improve reliability while maintaining the basic DC contact charging structure.
Solution Approach 2:
The charging member uses a composite structure with a conductive substrate and an elastic layer containing conductive particles dispersed in a resin matrix. This composite material approach enables simultaneous achievement of electrical conductivity for voltage distribution and elastic properties for consistent contact, thereby suppressing color streaks without significantly increasing structural complexity.
2Reliability
If the resistance component R is outside the specified range, then the charging member structure is simpler to manufacture, but discharge voltage varies causing color streaks
Solution Approach 1:
The patent specifies precise parameter ranges for resistance component R (4.0×10^4 Ω or more and 1.0×10^6 Ω or less) and impedance Z (over 3.6×10^4 Ω and 3.5×10^5 Ω or less) to ensure discharge voltage consistency. By controlling these parameters within defined ranges, the patent achieves reliable discharge while providing clear manufacturing targets that balance ease of production with performance requirements.
3Reliability
If the impedance Z is too low or too high, then the charging member is easier to manufacture, but charge transfer is inconsistent leading to color streaks
Solution Approach 1:
The patent defines a specific impedance range (over 3.6×10^4 Ω and 3.5×10^5 Ω or less) to ensure consistent charge transfer. This parameter control approach resolves the contradiction by providing clear specifications that guide manufacturing while ensuring reliable charge transfer consistency, avoiding both excessively low and high impedance conditions that would cause color streaks.
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 optimized charging member effectively suppresses color streaks and discharge omission by maintaining consistent voltage and charge transfer, improving image quality and extending the lifespan of electrophotographic photoreceptors.
Implementation Method 1
When measured by an alternating-current impedance method within a range of 1 MHz to 1 mHz in an environment at a temperature of 28° C. and a humidity of 85%, a resistance component R of an impedance within a range of 1 Hz to 100 Hz is 4.0×104 Ω or more and 1.0×106 Ω or less and an impedance Z within a range of 1 Hz to 100 Hz is over 3.6×104 Ω and 3.5×105 Ω or less
Data Source
AI summary
A charging member of a contact charging system that applies only a direct-current voltage to the charging member includes a conductive substrate, an elastic layer disposed on the conductive substrate, and a surface layer disposed on the elastic layer. When measured by an alternating-current impedance method within a range of 1 MHz to 1 mHz in an environment at a temperature of 28° C. and a humidity of 85%, a resistance component R of an impedance within a range of 1 Hz to 100 Hz is 4.0×104 Ω or more and 1.0×106 Ω or less and an impedance Z within a range of 1 Hz to 100 Hz is over 3.6×104 Ω and 3.5×105 Ω or less.