Developing Device Magnetic Pole Arrangement Suppresses Fog
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing developing devices for electrostatic latent images suffer from image defects such as vertical stripe-shaped fog due to unwanted developer movement between magnetic poles, leading to improper developer delivery and deposition on the image bearing member.
Innovation Solution
A developing device with a specific magnetic pole arrangement and configuration, including a first rotatable member with a first magnet having distinct magnetic poles and a second rotatable member with a second magnet, where the magnetic flux densities and pole positions are optimized to ensure that the attracting force between the first and second feeding poles is not more than the repelling force, thereby suppressing developer movement and image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a magnetic field is used to deliver developer from the first developing roller to the second developing roller, then developer delivery is achieved, but unwanted developer movement occurs between magnetic poles causing vertical stripe-shaped fog
Solution Approach 1:
The patent applies local quality by creating different magnetic field strengths at different locations. The first magnet is designed with a first magnetic field strength at the first magnetic pole and a second magnetic field strength at the second magnetic pole, where the first strength is greater than the second strength. This local variation in magnetic field strength ensures that developer is effectively delivered to the second developing roller while preventing unwanted movement and floating between the poles, thus eliminating the vertical stripe-shaped fog defect.
2Productivity
If the magnetic field strength between magnetic poles is increased to improve developer delivery, then delivery efficiency improves, but developer floating and deposition on image bearing member increases
Solution Approach 1:
The patent applies parameter changes by varying the magnetic field strength parameter at different locations. Specifically, the first magnetic field strength at the first magnetic pole is set to be greater than the second magnetic field strength at the second magnetic pole. This parameter variation allows the system to maintain strong enough magnetic field for effective developer delivery while preventing the field from being uniformly strong enough to cause developer floating and deposition on the image bearing member.
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 optimized magnetic pole arrangement and configuration effectively suppress the occurrence of image defects like vertical stripe-shaped fog, ensuring stable and efficient developer delivery and improved image quality.
Implementation Method 1
delivery of the developer is made by a magnetic field formed between a delivering pole of a first magnet provided in the first developing roller and a receiving pole of a second magnet provided in the second developing roller
Implementation Method 2
between the first magnetic pole and the second magnetic pole, a magnetic field for attracting the developer to each of the rollers is generated
Data Source
AI summary
In a case where a maximum magnetic flux density position of the second feeding pole is a point A, an absolute value of a magnetic flux density maximum of a first feeding pole is MB, a maximum magnetic flux density position of the first feeding pole is a point B, an absolute value of a magnetic flux density maximum of a delivering pole is MC, a maximum magnetic flux density position of the delivering pole is a point C, a rectilinear line distance between the points A and B is L1, a rectilinear line distance between the points A and C is L2, and an angle formed by a rectilinear line AB connecting the points A and B and a rectilinear line AC connecting the points A and C is θ, the following relationship is satisfied: the following relationship is satisfied: MB/L12≤(MC/L22)×cos θ.