Charging Roller Cleaning With Elastic Foam Modulus Matching
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Solution Overview
Problem
Conventional cleaning methods for charging rollers in image forming apparatuses are ineffective in removing toner and external additives, leading to charging defects and image defects such as uneven density and streaks in halftone images, and can result in complex maintenance due to clogging or the need for frequent replacement of cleaning components.
Innovation Solution
The image forming apparatus and process cartridge employ a cleaning roller with an elastic foam layer that has a lower storage elastic modulus than the charging roller, ensuring effective removal of toner and external additives by maintaining a specific relationship between their elastic moduli, thereby preventing contamination and reducing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning blade is used to clean the charging roller, then toner and external additives can be removed from the surface, but the cleaning effectiveness decreases over time as contamination accumulates in recessed portions
Solution Approach 1:
The patent changes the physical parameter of the cleaning member from a rigid cleaning blade to an elastic foam roller with specific elastic properties. The elastic foam layer can deform to access and clean recessed portions of the charging roller surface, maintaining cleaning effectiveness throughout the service life without degradation
Solution Approach 2:
The cleaning member uses a porous elastic foam structure that can penetrate into recessed portions of the charging roller surface. The porous structure allows the foam to conform to surface irregularities and effectively remove contamination from areas that a flat cleaning blade cannot reach
2Reliability
If a brush is used to clean the charging roller, then toner can be removed, but external additives with particle diameters from several nm to several hundred nm cannot be effectively removed
Solution Approach 1:
The patent changes the cleaning mechanism from mechanical brush bristles to elastic deformation of a foam material. The elastic foam can deform to conform to the charging roller surface and apply uniform pressure across all surface areas, effectively removing external additives of various sizes including nanoscale particles that a brush cannot reach
Solution Approach 2:
The patent replaces the mechanical brush system with an elastic foam system that uses elastic deformation rather than mechanical bristle contact. This substitution allows the cleaning member to adapt its shape to the surface geometry and apply consistent cleaning pressure, effectively removing particles of all sizes without the limitations of brush bristle diameter
3Strength
If a cleaning roller with high storage elastic modulus is used, then the cleaning roller maintains its shape, but it cannot effectively remove toner and external additives from the charging roller surface
Solution Approach 1:
The patent optimizes the storage elastic modulus parameter of the foam material to a specific range (10^5 to 10^7 Pa). This parameter optimization allows the foam to be soft enough to deform and conform to the charging roller surface for effective cleaning, while maintaining sufficient shape stability during operation
Solution Approach 2:
The patent establishes a specific relationship between the storage elastic modulus of the foam layer and the surface of the charging roller, requiring the foam's storage elastic modulus to be lower than that of the charging roller surface. This parameter relationship ensures the foam can effectively deform to contact and clean all surface areas including recessed portions
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
This configuration enhances the cleaning efficiency of charging rollers, reducing image defects and simplifying maintenance by effectively removing toner and external additives, thus improving the quality and longevity of the process cartridge.
Implementation Method 1
a cleaning roller provided with an elastic foam layer contacting the surface of the charging roller and configured to be rotated in contact with the rotating charging roller and clean the surface of the charging roller
Data Source
AI summary
An image forming apparatus includes an image bearing member, a charging roller, a cleaning roller and a developing member. The charging roller is provided with a surface contacting a surface of the image bearing member and charges the surface of the image bearing member. The cleaning roller is provided with an elastic foam layer contacting the surface of the charging roller cleans the surface of the charging roller. A storage elastic modulus of the surface of the charging roller measured in a measuring environment of 23° C., 50% RH and a measuring frequency of 10 Hz is defined as E′C and a storage elastic modulus of the elastic foam layer of the cleaning roller is defined as E′CC. The storage elastic modulus E′C of the surface of the charging roller and the storage elastic modulus E′CC of the elastic foam layer of the cleaning roller satisfy E′C>E′CC.