Development Device With Vertical Chambers for Stable Developer Release
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Solution Overview
Problem
There is a demand for size reduction in image forming apparatuses, particularly in color-printing models, which incorporate multiple development devices, and existing configurations do not efficiently utilize space to achieve this.
Innovation Solution
A development device is designed with a first and second conveyance chamber stacked vertically, incorporating a first and second stirring-conveyance member, a developer carrying member, and a regulation blade, with specific magnetic pole configurations to ensure stable developer release and collection, adhering to formulae (1) and (3) to maintain performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first and second conveyance chambers are disposed horizontally, then the developer container can accommodate both stirring-conveyance members, but the horizontal space required increases
Solution Approach 1:
The patent transitions from a horizontal arrangement of conveyance chambers to a vertical stacking configuration. The first conveyance chamber is positioned below the second conveyance chamber, utilizing the vertical dimension to reduce horizontal footprint. This dimensional change allows the development device to occupy less horizontal space while maintaining adequate volume for developer storage and circulation.
2Area of stationary object
If the conveyance chambers are stacked vertically, then horizontal space is reduced, but the magnetic pole configuration becomes more complex to ensure proper developer release
Solution Approach 1:
The magnetic member is divided into multiple magnetic poles (first magnetic pole, second magnetic pole, third magnetic pole, and fourth magnetic pole) arranged at different angular positions. Each pole serves a specific function: the first and second poles handle developer release, while the third and fourth poles manage developer attraction and circulation. This segmentation allows the complex magnetic function to be distributed across multiple simpler pole elements.
Solution Approach 2:
Different regions of the magnetic member are assigned different magnetic pole characteristics. The first magnetic pole is positioned to create a magnetic field for releasing developer from the development roller, while the second magnetic pole is positioned to attract and circulate developer back to the roller. This local differentiation of magnetic properties enables the vertical stacking configuration to function properly without requiring uniform magnetic characteristics throughout.
3Reliability
If the magnetic force of the release pole is increased, then developer release becomes more effective, but mechanical stress on the development roller increases
Solution Approach 1:
The magnetic pole configuration employs asymmetric positioning and varying magnetic force strengths across different poles. The release poles are positioned and sized to provide sufficient magnetic force for effective developer release, while the attraction poles are configured with different characteristics to balance the forces. This asymmetric design ensures that the magnetic field distribution is optimized for both release effectiveness and mechanical stress reduction, preventing excessive force concentration on any single point of the development roller.
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
This configuration allows for size reduction of the development device and image forming apparatus while ensuring stable developer release and improved durability, maintaining optimal developer concentration and reducing mechanical stress.
Implementation Method 1
a magnetic member that is fixed inside the development sleeve so as not to be rotatable and that has, along the rotation direction of the development sleeve, a plurality of magnetic poles including a regulation pole opposite the regulation blade, a main pole opposite the image carrying member, a release pole releasing developer carried on the developer carrying member, and an attracting pole attracting developer onto the developer carrying member
Data Source
AI summary
A development device includes a developer container having a first conveyance chamber and a second conveyance chamber above it, a first stirring-conveyance member, a second stirring-conveyance member, a developer carrying member, and a regulation blade. The developer carrying member includes a magnetic member having a regulation pole, a main pole, a release pole, and an attracting pole. A release start position at which the magnetic force of the release pole becomes 5 [mT] or less is below a straight line L1 horizontally passing through the center of a rotation shaft of the second stirring-conveyance member and when the central angle of a developer releasing region where the magnetic force between the release pole and the attracting pole is 5 [mT] or less is represented by X [°] and the peak magnetic force of the attracting pole is represented by Y [mT], Y≤2.1X−32.7 is satisfied.