Charging Roller Cleaning Sheet for Toner Residue Control
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Solution Overview
Problem
Existing charging devices for photosensitive drums in electrophotographic image forming apparatuses face issues with toner residue and charge control agents or external additives adhering to the charging roller, leading to defective charging and image defects, particularly in devices with longer lifespans.
Innovation Solution
A charging device with a cleaning member that includes a surface layer with roughening particles having a hardness higher than the charging member, and similar to or higher than the hardness of toner components, to effectively loosen and disperse adhering residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning roller is used to clean the charging roller, then the charging roller can be cleaned, but the device complexity and cost increase due to needing a supporting member for rotation
Solution Approach 1:
The invention extracts the cleaning function from a separate rotating cleaning roller and integrates it into a stationary cleaning sheet that simply contacts the charging roller surface. The cleaning sheet is fixed to a support member without requiring rotation mechanisms, thereby eliminating the complexity of supporting members while maintaining cleaning effectiveness through the charging roller's own rotation.
Solution Approach 2:
The cleaning sheet acts as an intermediary between the charging roller and the support member. Instead of directly coupling the cleaning function to a rotating mechanism, the cleaning sheet mediates by being stationary yet effective, using the charging roller's rotation to achieve cleaning without requiring its own rotation system.
2Device complexity
If a polyimide film cleaning sheet is used, then the device structure is simplified, but the cleaning effectiveness is insufficient for substantial toner residue and deposits
Solution Approach 1:
The cleaning sheet is constructed as a composite material combining a polyimide film base layer with a surface layer containing roughening particles. This composite structure provides both the flexibility and durability of polyimide and the enhanced cleaning capability of roughening particles, enabling effective removal of substantial toner residue and deposits while maintaining structural simplicity.
Solution Approach 2:
The cleaning sheet has different properties at different layers: the base layer provides structural support and flexibility, while the surface layer contains roughening particles for enhanced cleaning. This local differentiation of material properties allows the cleaning sheet to achieve superior cleaning effectiveness without increasing overall device complexity.
3Strength
If a cleaning member with hardness lower than toner components is used, then the charging roller surface is not damaged, but toner residues and charge control agents cannot be effectively removed
Solution Approach 1:
The cleaning member's hardness parameter is optimized by incorporating roughening particles with Mohs hardness similar to or higher than toner components. This parameter change enables the cleaning member to effectively remove toner residues and charge control agents while the controlled contact pressure and particle distribution prevent excessive damage to the charging roller surface.
Solution Approach 2:
The cleaning member has localized hard roughening particles on its surface rather than being uniformly hard throughout. This local quality concentration allows effective cleaning action at the contact points while the overall structure remains flexible and controlled, preventing excessive damage to the charging roller 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 effectively suppresses soiling of the charging roller, preventing defective charging and maintaining image quality by uniformly dispersing toner residues, even in devices with extended lifespans.
Implementation Method 1
the cleaning member includes at least a first layer that contains roughening particles and that comes into contact with the charging member; the Martens hardness of the first layer is higher than that of the surface of the charging member; the roughening particles have a Mohs hardness similar to or higher than that of a component of highest Mohs hardness in toner adhered to the surface of the charging member
Implementation Method 2
the cleaning member is configured to be pressed against the charging member, and be rubbed against a surface of the charging member by rotating the charging member
Data Source
AI summary
A charging device has: a charging member that charges an image bearing member; and a cleaning member that is pressed against the charging member, and that is rubbed against a surface of the charging member by rotating the charging member. The cleaning member includes at least a first layer that contains roughening particles and that comes into contact with the charging member. The Martens hardness of the first layer is higher than that of the surface of the charging member. The roughening particles have a Mohs hardness similar to or higher than that of a component of highest Mohs hardness in toner adhered to the surface of the charging member.