Urethane Foam Cleaning Member for Electrophotographic Photosensitive Member
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Solution Overview
Problem
Conventional cleaning blades in electrophotographic image forming apparatuses face issues with edge wear and chipping, leading to reduced scrapability and streaky image failures under varying environmental conditions, such as low temperature and low humidity, and high temperature and high humidity.
Innovation Solution
A process cartridge with an electrophotographic photosensitive member and a cleaning member featuring a urethane foam layer with a density of 200 to 500 kg/m3 and a 25% compressive load of 0.3 MPa or smaller, ensuring adequate elastic deformation modulus and followability, thereby maintaining low friction and effective toner sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cleaning blade is hardened by increasing isocyanurate group concentration, then edge wear is improved, but scrapability is lowered due to local chipping under low temperature and low humidity conditions
Solution Approach 1:
The invention changes the physical-chemical parameters of the cleaning member by using a urethane foam layer with specific density (200-500 kg/m³) and compressive load (0.3 MPa or smaller), replacing the conventional hardened rubber blade. This parameter change allows the cleaning member to maintain both edge durability and effective scrapability across different environmental conditions.
Solution Approach 2:
The invention employs a composite structure by using urethane foam as the cleaning member material, which combines the benefits of edge durability and adaptability. The foam structure provides both mechanical strength to prevent chipping and flexibility to maintain contact with the photosensitive member surface, resolving the contradiction between hardness and scrapability.
2Strength
If the cleaning blade hardness is optimized, then wear and chipping are improved, but scrapability is lowered due to settling under high temperature and high humidity conditions
Solution Approach 1:
The invention addresses the settling issue by carefully controlling the density and compressive load parameters of the urethane foam. The specific range of density (200-500 kg/m³) and compressive load (0.3 MPa or smaller) prevents excessive deformation under high temperature and humidity while maintaining sufficient contact pressure for effective cleaning.
Solution Approach 2:
The urethane foam structure provides local quality variations that allow different regions of the cleaning member to adapt to varying environmental conditions. The foam's cellular structure provides both cushioning against settling and maintained contact pressure where needed, ensuring consistent scrapability across different temperatures and humidity levels.
3Device complexity
If a conventional cleaning blade is used, then the structure is simple, but edge wear and chipping occur leading to reduced cleaning effectiveness
Solution Approach 1:
The invention replaces the simple rubber blade with a urethane foam cleaning member that has a cellular composite structure. This structure provides superior edge durability and consistent cleaning effectiveness while maintaining ease of use. The foam structure inherently resists wear and chipping while maintaining contact with the photosensitive member.
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 stabilizes high-quality electrophotographic image formation across different environments by improving edge wear resistance and maintaining cleaning effectiveness, preventing streaks and ensuring reliable image output.
Implementation Method 1
an elastic deformation modulus of a surface layer of the electrophotographic photosensitive member is 35% or larger
Implementation Method 2
to lower the friction between the photosensitive member and the cleaning blade
Data Source
AI summary
A process cartridge configured to be detachably attachable to a main body of an electrophotographic image forming apparatus, in which an occurrence of an image failure is suppressed, wherein the process cartridge includes an electrophotographic photosensitive member and a cleaning member arranged in contact with the electrophotographic photosensitive member, wherein an elastic deformation modulus of a surface layer of the electrophotographic photosensitive member is 35% or larger, and the cleaning member is formed of a urethane foam, wherein a density of the urethane foam is 200 to 500 kg/cm3, and a 25% compressive load of the urethane foam is 0.3 MPa or smaller.