Resin-Coated Ferrite Carrier for Electrophotographic Developer
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Solution Overview
Problem
Resin-coated ferrite carriers for electrophotographic developers face issues with non-uniform coating, offensive odors from organic solvents, and poor durability, leading to problems like fogging, carrier adhesion, and decreased image quality, especially in high-speed and full-color applications.
Innovation Solution
A resin-coated ferrite carrier is developed using a mixed resin of tetrafluoroethylene-hexafluoropropylene copolymer or tetrafluoroethylene-perfluoroalkylvinyl ether copolymer with polyamideimide resin and silicon oxide, coated using a water-based solvent to ensure uniformity and stability, improving charge and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silicone resin is used as the coating resin, then the carrier can be coated, but fogging in copy images and carrier adhesion occur due to charge quantity change caused by internal temperature rise
Solution Approach 1:
The patent changes the chemical composition parameters of the coating resin by using a fluorinated epoxy resin instead of silicone resin, and adjusts the coating amount to 0.01-10 wt% based on ferrite particles. This parameter change eliminates the fogging and carrier adhesion problems while maintaining coating uniformity.
Solution Approach 2:
The patent uses a composite coating resin system consisting of fluorinated epoxy resin combined with other resins in specific ratios. This composite material approach provides both uniform coating properties and stable charge characteristics, resolving the contradiction between manufacturing precision and reliability.
2Manufacturing precision
If a fluorinated epoxy resin is used as the coating resin, then the carrier can be coated, but toner scattering and fogging occur due to decreased charge of the toner spent by continuous printing
Solution Approach 1:
The patent optimizes the coating amount parameter to 0.01-10 wt% based on ferrite particles and adjusts the resin composition ratios. This parameter optimization maintains coating uniformity while preventing toner scattering and fogging by stabilizing charge characteristics during continuous printing.
Solution Approach 2:
The patent applies different resin components to different aspects of the coating function: fluorinated epoxy resin provides coating uniformity and adhesion, while other resin components maintain charge stability. This local quality differentiation resolves the contradiction between manufacturing precision and reliability.
3Manufacturing precision
If a fluorinated epoxy resin is used as the coating resin, then the carrier can be coated, but the solvent needs to include an organic solvent with a strong odor such as methyl isobutyl ketone, causing offensive odors
Solution Approach 1:
The patent converts the harmful effect of requiring strong odor organic solvents into a benefit by formulating a water-based or low-odor solvent system that still enables effective coating. This eliminates offensive odors while maintaining coating quality through optimized resin-solvent interactions.
Solution Approach 2:
The patent changes the solvent type parameter from strong odor organic solvents to water-based or low-odor alternatives. This parameter change eliminates harmful odors while maintaining coating quality through adjusted resin composition and coating parameters.
4Ease of manufacture
If spherical ferrites are used as the carrier core material, then the carrier can be produced, but they are inferior in resistance against toner spent
Solution Approach 1:
The patent uses a composite structure combining ferrite core particles with a resin coating layer. This composite material approach provides both ease of manufacture (using standard ferrite production) and improved toner spent resistance through the protective resin coating that maintains charge stability and prevents toner aggregation.
Solution Approach 2:
The patent applies a resin coating shell around the spherical ferrite core. This thin film approach maintains the ease of manufacture of spherical ferrites while providing the necessary toner spent resistance through the flexible resin layer that prevents direct contact between ferrite and toner, reducing charge loss and toner aggregation.
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 provides a stable and uniform resin coating that enhances charge stability, reduces fog and carrier adhesion, and maintains favorable image density and environmental dependability over a long period, effectively addressing the limitations of previous technologies.
Implementation Method 1
a resin-containing aqueous solution prepared by dissolving a tetrafluoroethylene-hexafluoropropylene copolymer or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and a silicon oxide in a resin solution in which a polyamideimide resin is dissolved in a water-based solvent
Implementation Method 2
the surface of ferrite particles is coated with the above resin by using the aqueous solution
Data Source
AI summary
A resin-coated ferrite carrier having a uniform resin coating and emitting no offensive odors, etc., its production method, and an electrophotographic developer which comprises the resin-coated ferrite carrier, is excellent in the charge stability and image quality stability over a long period, causes less fogging of image or carrier adhesion, is favorable in the image density and environmental dependency, and can fully respond to high-speed and full-color imaging, are provided. The resin-coated ferrite carrier for the electrophotographic developer is characterized in that the surface of ferrite particles is coated with a mixed resin of a tetrafluoroethylene-hexafluoropropylene copolymer or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and a polyamideimide resin, and that the mixed resin contains a silicon oxide.