Charging Member Surface Roughness for Toner Adhesion
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Solution Overview
Problem
Contact charging apparatuses face issues with toner or external additives attaching to the charging member, leading to fluctuations in surface resistance and unstable charging properties, which can result in image defects like white or black spots.
Innovation Solution
A charging member with a conductive outermost layer having a surface roughness of 2 μm to 20 μm, containing resin and specific conductive particles, is used to prevent attachment of toner or external additives, ensuring stable charging and high contamination resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact charging apparatus uses a charging member with a smooth surface, then charging efficiency is improved, but toner or external additives attach to the charging member causing surface resistance fluctuation and unstable charging
Solution Approach 1:
The patent applies local quality by creating a surface with specific roughness characteristics (Rz of 2-20 μm) on the charging member's outermost layer. This localized surface modification allows the charging member to maintain good charging contact while the controlled roughness prevents toner adhesion, thus resolving the contradiction between charging efficiency and toner attachment resistance.
Solution Approach 2:
The patent changes the surface roughness parameter of the charging member from smooth to a controlled rough state with Rz of 2-20 μm. This parameter change fundamentally alters the interaction between the charging member surface and toner particles, reducing attachment while maintaining charging function, thereby resolving the technical contradiction.
2Object-affected harmful factors
If AC current is reduced to minimize damage to photoreceptor, then photoreceptor protection is improved, but charging fluctuation increases causing white or black spots
Solution Approach 1:
The patent applies local quality by modifying only the surface layer of the charging member with controlled roughness, while maintaining the bulk charging properties. This allows reduced AC current to be used for photoreceptor protection while the surface roughness ensures uniform charge distribution, preventing charging fluctuations and image defects.
Solution Approach 2:
The surface roughness structure acts as an intermediary between the charging member and the photoreceptor. It allows effective charging transfer even at lower AC current levels, mediating between the need for photoreceptor protection and the need for charging uniformity, thus preventing both damage and defects.
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 provides stable and consistent charging with reduced fluctuations, maintaining image quality over a long period and preventing image defects by inhibiting toner or external additive attachment.
Implementation Method 1
has a ten-point average surface roughness Rz of about 2 μm to about 20 μm
Implementation Method 2
comes into contact with a body to be charged, in a state where a voltage is applied, to charge the body to be charged
Data Source
AI summary
The present invention provides a charging member that includes at least: a base material; and a conductive outermost layer that is disposed on the base material, comes into contact with a body to be charged, has a ten-point average surface roughness Rz of about 2 μm to about 20 μm, and contains (A) a resin and (B) specific conductive particles for forming the surface roughness, the charging member coming into contact with the body to be charged, in a state where a voltage is applied, to charge the body to be charged.