Charging Roller Speed Differential for Uniform Potential
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Solution Overview
Problem
Existing electrophotographic apparatuses with direct current charging systems face challenges in achieving uniform surface potential and efficient residual toner collection due to nonuniform surface charging and instability, particularly in cleaner-less systems without a cleaning blade.
Innovation Solution
An electrophotographic apparatus with a cylindrical photosensitive member, a charging roller that applies direct current voltage, and a driving force transmission creating a peripheral speed difference between the photosensitive member and the charging roller, along with an undercoat layer containing metal oxide particles for uniform charging and residual toner collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning blade is used to remove residual toner, then residual toner removal is effective, but device complexity and size increase
Solution Approach 1:
The invention extracts and eliminates the cleaning blade component from the system by implementing a cleaner-less architecture. The residual toner collection function is achieved through the interaction between the charging roller and photosensitive member, where the peripheral speed difference creates relative motion that naturally collects residual toner back to the developing device without requiring a separate cleaning mechanism.
Solution Approach 2:
The system uses its own operational components (charging roller and photosensitive member) to perform the residual toner collection function. The peripheral speed difference between these components during operation creates the necessary relative motion to transport residual toner, allowing the system to self-manage toner collection without external cleaning devices.
2Ease of manufacture
If direct current voltage is applied to charge the photosensitive member, then charging simplicity is improved, but surface potential uniformity deteriorates
Solution Approach 1:
The invention introduces dynamic motion between the charging roller and photosensitive member through peripheral speed difference. This relative motion continuously renews the contact interface during charging, preventing localized charge accumulation and ensuring uniform surface potential distribution across the photosensitive member while maintaining the simplicity of direct current voltage application.
3Productivity
If peripheral speed difference is increased between charging roller and photosensitive member, then residual toner collection efficiency is improved, but charging uniformity deteriorates
Solution Approach 1:
The invention optimizes the peripheral speed difference parameter within a specific range (5-50 m/min) to achieve the best balance between residual toner collection efficiency and charging uniformity. This parameter optimization ensures that the relative motion is sufficient for effective toner collection while maintaining stable and uniform charging across the photosensitive member surface.
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 enables high-level residual toner collection and uniform charging, improving image formation quality and reducing the size of electrophotographic apparatuses while eliminating the need for a cleaning blade.
Implementation Method 1
a charging roller that is disposed so as to be in contact with the electrophotographic photosensitive member and applies a direct current voltage to charge the electrophotographic photosensitive member
Implementation Method 2
a driving force transmission that transmits a driving force which causes rotation so that contact portions of the electrophotographic photosensitive member and the charging roller move in the same direction and a peripheral speed of the charging roller is higher than a peripheral speed of the electrophotographic photosensitive member
Implementation Method 3
the undercoat layer contains metal oxide particles, and the undercoat layer has a volume resistivity of 1×10^7 Ω·cm or more and 1×10^14 Ω·cm or less
Data Source
AI summary
An electrophotographic apparatus includes a cylindrical electrophotographic photosensitive member, a charging roller that is disposed in contact with the electrophotographic photosensitive member and applies a direct current voltage to charge the electrophotographic photosensitive member, and a driving force transmission that transmits a driving force which causes rotation so that contact portions of the electrophotographic photosensitive member and the charging roller move in the same direction and the peripheral speed of the charging roller is higher than the peripheral speed of the electrophotographic photosensitive member, wherein the undercoat layer of the electrophotographic photosensitive member contains metal oxide and the undercoat layer has a volume resistivity of 1×107 Ω·cm or more and 1×1014 Ω·cm or less.