Developing Apparatus Magnetic Sealing for High-Speed Toner Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-speed electrophotographic copying machines, the magnetic brush developing method faces challenges with developer leakage and scattering due to increased centrifugal force, leading to contamination and reduced apparatus functionality, especially when using multiple development sleeves with repulsive magnetic fields and magnetic seal members of identical polarity.
Innovation Solution
A developing apparatus with multiple developer carrying members employs magnetically attractive toner or carriers, utilizing magnetic field generating means with poles of different polarities to prevent developer leakage by forming a magnetic brush that seals the developer, and using magnetizable plates to concentrate the magnetic field and prevent areas of low magnetic force, ensuring effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the peripheral speed of the development sleeve is increased to enhance development efficiency, then development efficiency is improved, but centrifugal force on the developer increases causing developer scattering and contamination
Solution Approach 1:
The patent applies magnetic field generating means to convert the harmful centrifugal force effect into a beneficial magnetic attraction effect. The magnetic field generates a magnetic brush that holds the developer particles against the development sleeve surface, preventing scattering caused by centrifugal force while allowing high peripheral speeds for efficient development.
Solution Approach 2:
The patent changes the physical state of developer holding from purely mechanical (relying on centrifugal force balance) to magnetic (relying on magnetic field attraction). By introducing magnetic field strength as a new parameter, the system can maintain developer retention at higher rotational speeds where conventional mechanical retention fails.
2Reliability
If magnetic seal members of identical polarity are used to seal the developer, then sealing is achieved, but areas of low magnetic force occur causing developer leakage
Solution Approach 1:
The patent introduces asymmetry in the magnetic field configuration by using magnetic poles of different polarities (N and S poles) arranged alternately or in specific patterns. This asymmetric arrangement creates a non-uniform magnetic field with strong gradient regions that effectively trap developer particles, eliminating the low magnetic force areas that occur with identical polarity arrangements.
Solution Approach 2:
The patent uses a cylindrical development sleeve with curved surface geometry combined with radially arranged magnetic poles. This curved geometry creates a continuous magnetic field distribution around the sleeve, ensuring uniform developer retention without dead zones or leakage points that would occur with flat or improperly configured surfaces.
3Productivity
If multiple development sleeves are used to handle high-speed development, then development capacity is increased, but the load on each sleeve increases reducing lifespan
Solution Approach 1:
The patent replaces the mechanical friction-based developer retention system with a magnetic field-based system. The magnetic brush holds developer particles through magnetic attraction rather than mechanical friction, dramatically reducing the mechanical load and wear on the development sleeves while enabling multiple sleeves to operate at high speeds for increased capacity.
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 prevents developer leakage and scattering, maintaining high development efficiency and image quality even at higher peripheral speeds, while reducing the load on development sleeves and prolonging their lifespan by ensuring continuous magnetic attraction and sealing.
Implementation Method 1
a magnetic field generating means with poles of different polarities to prevent developer leakage by forming a magnetic brush
Implementation Method 2
utilizing magnetic field generating means with poles of different polarities to prevent developer leakage by forming a magnetic brush that seals the developer
Implementation Method 3
using magnetizable plates to concentrate the magnetic field and prevent areas of low magnetic force, ensuring effective sealing
Implementation Method 4
the magnetic brush developing method faces challenges with developer leakage and scattering due to increased centrifugal force
Data Source
AI summary
A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.