Dual Developing Roller Magnetic Layout for Cleaner Toner Transfer
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Solution Overview
Problem
Existing developing apparatuses face issues with developer transferability between developing rollers due to excessive magnetic flux density, leading to developer agglomeration and image defects.
Innovation Solution
A developing apparatus design with specific magnetic pole arrangements on first and second rotatable developing members, where the magnetic flux densities and rotational directions are optimized to enhance developer transfer while minimizing developer deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the magnetic flux density of the receiving pole of the magnet in the second developing roller is excessively increased to deliver the developer against gravity, then the developer transferability is improved, but the developer deteriorates due to shearing force causing clusters of agglomerates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the magnetic flux density of the receiving pole and optimizing the rotational speed ratio between the first and second developing rollers. By adjusting these parameters, the system achieves sufficient developer transfer against gravity while preventing excessive magnetic force that would cause developer deterioration and agglomeration.
Solution Approach 2:
The patent employs dynamics by making the rotational speed of the developing rollers variable rather than fixed. The rotational speed ratio between the first and second developing rollers is optimized to work together with the magnetic flux density to achieve smooth developer transfer. This dynamic adjustment allows the system to adapt to different operating conditions and maintain developer quality during transfer.
2Force
If the magnetic flux density is increased to deliver developer from the first developing roller to the second developing roller positioned higher in vertical direction, then the developer delivery against gravity is improved, but the shearing force on developer increases causing image defects
Solution Approach 1:
The patent applies parameter changes by precisely controlling the magnetic flux density of the receiving pole and optimizing the rotational speed ratio between the first and second developing rollers. By adjusting these parameters, the system achieves sufficient developer transfer against gravity while preventing excessive magnetic force that would cause developer deterioration and agglomeration.
Solution Approach 2:
The patent employs dynamics by making the rotational speed of the developing rollers variable rather than fixed. The rotational speed ratio between the first and second developing rollers is optimized to work together with the magnetic flux density to achieve smooth developer transfer. This dynamic adjustment allows the system to adapt to different operating conditions and maintain developer quality during transfer.
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
Improves developer transfer efficiency and reduces developer deterioration, preventing image defects by aligning magnetic forces and gravitational forces effectively.
Implementation Method 1
a first magnet provided non-rotatably and stationarily inside the first rotatable developing member, the first magnet having a first magnetic pole and a second magnetic pole provided downstream of the first magnetic pole and adjacent to the first magnetic pole in a rotational direction of the first rotatable developing member and having the same magnetic polarity as that of the first magnetic pole
Implementation Method 2
a second magnet provided non-rotatably and stationarily inside the second rotatable developing member, the second magnet having a third magnetic pole disposed to face the first magnetic pole and having a different magnetic polarity from that of the first magnetic pole
Implementation Method 3
the delivery of the developer from the first developing roller to the second developing roller positioned higher in the vertical direction is performed against gravity
Data Source
AI summary
A first maximum position where a magnetic flux density of a first magnetic pole is maximum is positioned downstream of a first developing position and upstream of a first closest position. A second maximum position where a magnetic flux density of a third magnetic pole is maximum is positioned downstream of a second closest position and upstream of a second developing position. A relationship of r1×θ1>r2×θ2 is satisfied, in a case where r1 represents a radius of a first rotatable developing member, r2 represents a radius of a second rotatable developing member, θ1 represents an angle from the first maximum position to the first closest position in the rotational direction of the first rotatable developing member, and θ2 represents an angle from the second closest position to the second maximum position in the rotational direction of the second rotatable developing member.