Urethane Silicone Developing Roller Banding Reduction
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Solution Overview
Problem
The pressure development process in electrophotographic image forming apparatuses often results in line-shaped image non-uniformity, known as banding, due to components exuding from the developer feed roller adhering to the developing roller, especially in high-temperature and high-humidity environments, leading to non-uniform triboelectric charge quantities on the roller surface.
Innovation Solution
A developing roller with a surface layer comprising a urethane resin and a non-reactive silicone compound having a polyether moiety with 3 to 9 carbon atoms in its ether repeating unit, which maintains consistent chargeability and reduces the impact of exudates from the developer feed roller, thereby minimizing banding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a urethane resin is used as the surface layer material of the developing roller, then the roller can provide good triboelectric charge properties for developer adhesion, but the roller surface becomes tacky and generates large friction, causing components to exude and adhere during prolonged contact, resulting in banding
Solution Approach 1:
The surface layer is formed as a composite material comprising a urethane resin base polymer and a polysiloxane modifier. The urethane resin provides the necessary triboelectric charge properties for developer adhesion, while the polysiloxane component reduces surface tackiness and friction. This composite structure allows simultaneous achievement of good charge properties and reduced component exudation during prolonged contact between the developing roller and developer feed roller.
2Ease of manufacture
If the electrophotographic apparatus is kept unoperated for a long period with the developing roller and developer feed roller in contact, then the apparatus can be stored conveniently, but components exude from the developer feed roller and adhere to the developing roller, causing banding in images
Solution Approach 1:
The polysiloxane is incorporated into the urethane resin surface layer in advance during manufacturing, creating a modified surface composition before the apparatus is put into service. This preliminary modification of the surface layer prevents component exudation and adhesion during prolonged storage periods, thereby preventing banding when the apparatus is later operated. The surface layer is prepared beforehand to resist the harmful effects of prolonged contact during storage.
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 reduces banding in electrophotographic images and ensures high-grade image formation even after prolonged periods of inactivity and exposure to high-temperature, high-humidity conditions, maintaining uniform triboelectric charge and image density.
Implementation Method 1
The developing roller used in such a developing assembly has a stated electrical resistance value, and is required not to change in electrical resistance... The thin-layer developer adheres to the electrostatic latent images formed on the photosensitive drum
Data Source
AI summary
A developing member is disclosed which can lessen the occurring of banding. The developing member has a shaft member, an elastic layer provided on the shaft member, and a resin layer provided on the surface, wherein the resin layer contains a urethane resin and a non-reactive silicone compound, and the non-reactive silicone compound has a polyether moiety whose total number of carbon atoms ranges from 3 to 9.