Process Cartridge Injection Charging for High-Speed Image Stability
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Solution Overview
Problem
Existing electrophotographic image forming apparatuses experience fogging in high-temperature and high-humidity environments and reduced dot reproducibility in low-temperature and low-humidity environments due to fluctuations in charge imparted to the developer, especially at high process speeds.
Innovation Solution
A process cartridge and electrophotographic image forming apparatus with a developer carrying member and a developer layer thickness control member that apply controlled voltages to ensure consistent charge injection, using a conductive substrate with a resin layer and a metal film, and adhering to specific impedance and ionization potential conditions to minimize charge leakage and environmental influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection charging method with high voltage is applied to developer layer thickness control member, then charge can be transferred to developer more quickly and appropriate charge can be imparted even at high process speed, but fogging occurs in high-temperature and high-humidity environment and charge quantity fluctuates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the voltage applied to the developer layer thickness control member (blade) within a specific range of 0 to 100V. This voltage control, combined with specific material selections for the developer carrying member and blade, stabilizes the charge quantity transferred to the developer during high-speed processing, preventing fogging while maintaining appropriate charging even at increased process speeds.
Solution Approach 2:
The patent employs composite materials by specifying particular material combinations for the developer carrying member and blade. These materials are selected based on their triboelectric properties to ensure stable charge transfer characteristics. The composite structure of the developer carrying member (with specific surface treatment) and the blade material works together to maintain consistent charge injection under varying environmental conditions and high-speed operation.
2Device complexity
If conventional triboelectric charging method is used, then device complexity is reduced, but charge transfer speed is insufficient for high process speed and environmental influence increases
Solution Approach 1:
The patent introduces an intermediary mechanism by applying a controlled voltage to the developer layer thickness control member (blade). This voltage application acts as an intermediary that enhances the charge transfer process without requiring a complete overhaul of the charging system. The blade serves as both a thickness control element and a charged surface that facilitates rapid charge transfer to the developer, bridging the gap between simple triboelectric charging and high-speed charging requirements.
3Measurement precision
If voltage is applied to developer layer thickness control member to increase charge transfer, then charge quantity can be controlled, but charge leakage occurs and dot reproducibility decreases in low-temperature and low-humidity environment
Solution Approach 1:
The patent applies parameter changes by optimizing the voltage range applied to the blade (0 to 100V) and selecting specific material combinations for the developer carrying member and blade. These parameter optimizations ensure that sufficient charge is transferred to the developer for good dot reproducibility in low-temperature, low-humidity environments, while preventing excessive charge that would cause fogging in high-temperature, high-humidity conditions.
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 fogging and coarseness, ensuring high-quality images with uniform charge distribution across varying environmental conditions and process speeds.
Implementation Method 1
a method of imparting charge to a developer may be changed from the conventional triboelectric charging method to an injection charging method. In the injection charging method, a high voltage is applied to a developer layer thickness control member that contacts a developer carrying member, so that a charge could be transferred to the developer more quickly.
Implementation Method 2
a corona discharger that has a grid portion with a width of 3.0 mm is arranged such that a distance between the grid portion and the outer surface of the developer carrying member is 1.0 mm and a width direction of the grid portion coincides with an axial direction of the developer carrying member in an environment with a temperature of 23° C. and a relative humidity of 50%, a voltage of 8 kV is applied to the grid portion, the corona discharger is moved along the axial direction of the developer carrying member relative thereto at a speed of 400 mm/sec to charge the outer surface of the developer carrying member
Implementation Method 3
a metal film is provided directly on an outer surface of the developer carrying member, and an AC voltage with an amplitude of 50 V is applied with a frequency being changed between 1.0×10−1 to 1.0×105 Hz while applying a DC voltage of 50 V between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, an impedance at a frequency of 1.00×100 to 1.00×101 Hz is 1.00×106Ω or more
Data Source
AI summary
A process cartridge comprising a developer carrying member and a developer layer thickness control member that contacts the developer carrying member and controls the layer thickness of the developer carried on the developer carrying member, wherein the developer carrying member comprises a substrate comprising a conductive outer surface, and a resin layer present on a side of the outer surface of the substrate, an impedance measured by providing a metal film directly on an outer surface of the developer carrying member is 1.00×106Ω or more, a specific relationship is satisfied between the ionization potential I(T) of the developer and the ionization potential I(R) of the outer surface of the developer carrying member, and the maximum value of the potential measured on the outer surface of the developer carrying member is less than 20.0 V.