Magnetic Seal for Development Sleeve Leakage
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Solution Overview
Problem
High-speed operation of electro-photographic image forming devices leads to developer leakage between development sleeves, causing contamination and reduced device functionality, despite efforts to maintain a magnetic seal.
Innovation Solution
A development device with multiple development sleeves featuring strategically positioned magnetic poles and magnet members to create a magnetic seal, including a zero Gauss zone, which prevents developer leakage by forming a repulsive magnetic field and ensuring proper developer conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the peripheral speed of the development sleeve is increased to improve development efficiency, then the development capability is enhanced, but centrifugal force acting on the developer increases causing scattering and contamination
Solution Approach 1:
The invention divides the development process into multiple stages using two or more development sleeves arranged in sequence. Each sleeve handles a portion of the development task, allowing the system to maintain high productivity while each individual sleeve operates at controlled speeds that prevent developer scattering.
Solution Approach 2:
Magnetic seal members are introduced as intermediary elements between adjacent development sleeves. These magnetic seals create magnetic fields that contain the developer within the development container, preventing scattering and contamination even when sleeves rotate at high speeds for improved efficiency.
2Reliability
If magnet members are disposed at the end portions of development sleeves to suppress developer leakage, then developer containment is improved, but magnetic seal property deteriorates when peripheral speed is increased
Solution Approach 1:
Magnetic seal members with specific polarities are strategically positioned at critical locations (end portions and intermediate positions) of the development sleeves. The polarity configuration is optimized for each location to provide both leakage suppression and high-speed magnetic seal functionality simultaneously.
Solution Approach 2:
The magnetic seal system combines multiple magnet members with different polarities arranged in a composite configuration. This includes magnet members with the same polarity as the delivery magnetic pole and magnet members with opposite polarity, creating a composite magnetic field structure that maintains seal integrity at high speeds while preventing leakage.
3Productivity
If multiple development sleeves are used to prolong development time and enhance capability, then development efficiency is improved, but developer leaks from between upstream and downstream sleeves
Solution Approach 1:
Magnetic seal members serve as intermediary magnetic barriers between upstream and downstream development sleeves. These seals create magnetic fields that prevent developer from leaking across the interface between adjacent sleeves, enabling multi-stage development without substance loss.
Solution Approach 2:
Magnetic seal members are positioned in advance at strategic locations between development sleeves to create preliminary magnetic barriers. This preliminary anti-action prevents developer leakage before it can occur, allowing multiple sleeves to operate in close proximity without cross-contamination.
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
Effectively suppresses developer leakage between development sleeves while maintaining a strong magnetic seal, even at high speeds, thereby enhancing image forming efficiency and reducing contamination.
Implementation Method 1
a plurality of magnetic poles including at least a first magnetic pole provided to face the second developer bearing member
Implementation Method 2
a first magnet member provided in an end portion in an axis direction of the first developer bearing member
Implementation Method 3
If the peripheral speed of the development sleeve is increased in accordance with the request for further increase of the speed, however, leak of the developer, which cannot be neglected, occurs from between two sleeves depending upon a position relation between a repulsion pole of the downstream development sleeve and the magnet member
Implementation Method 4
A second magnet member provided in an end portion in an axis direction of the second developer bearing member... the second magnet member being disposed to face a zero Gauss zone, which becomes 50 Gauss or less in magnetic flux density
Data Source
AI summary
A development device including a plurality of development sleeves and conducting development sleeve end portion seal using magnet members, a second magnetic pole and a third magnetic pole of a magnet incorporated in a second developer bearing member form repulsive poles. A position on the magnet member facing a rotation direction downstream end of the second developer bearing member is configured to be included in a zero Gauss zone. As a result, developer leak in the development sleeve rotation direction from between two development sleeves is suppressed.