Grooved Magnet for Two-Component Developer Peeling
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Solution Overview
Problem
The challenge in developing devices is to ensure efficient peeling of a two-component developer with reduced toner density from a developing sleeve, especially with smaller device sizes, where the narrow magnetic field configuration hinders proper separation, leading to potential image failures and increased device size when external magnets are used.
Innovation Solution
A magnet configuration with a groove along its longitudinal direction is implemented, creating two peel-off regions by adjusting the magnetic force pattern to maximize magnetic flux density and minimize magnetic force regions, allowing for effective peeling without external magnets, thus maintaining device compactness and improving peeling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the developing sleeve is reduced to decrease device size, then the device becomes more compact, but the distance between magnetic poles becomes short and the peel-off region becomes narrow, making it difficult for the developer to separate from the developing sleeve
Solution Approach 1:
The magnet is divided into multiple magnetic poles (first magnetic pole and second magnetic pole with same polarity) arranged adjacent to each other in the rotation direction. This segmentation creates multiple magnetic force regions and multiple peel-off regions, ensuring reliable developer separation even with a narrow overall peel-off region caused by reduced developing sleeve diameter.
Solution Approach 2:
The magnet is designed with non-uniform magnetic flux density distribution, featuring a first maximum peak position at the first magnetic pole and a second maximum peak position at the second magnetic pole. This local variation in magnetic flux density creates corresponding magnetic force regions that facilitate effective developer peeling at specific locations, compensating for the narrow peel-off region caused by small device size.
2Reliability
If a new magnet is externally added near the stripping pole to improve peelability, then the peeling efficiency improves, but the space for arranging the new magnet increases the device size
Solution Approach 1:
The function of the stripping pole and the additional magnetic pole are merged into a single integrated magnet structure. The magnet includes both the first magnetic pole (stripping pole) and the second magnetic pole (additional pole with same polarity) arranged adjacent to each other, eliminating the need for a separate external magnet and avoiding increased device size.
Solution Approach 2:
Instead of adding a magnet in the radial direction (outside the developing sleeve), the solution adds magnetic poles in the axial direction (along the rotation direction of the developing sleeve). This dimensional transition allows the second magnetic pole to be positioned adjacent to the first magnetic pole within the same radial space, improving peelability without increasing the radial device size.
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 enhances the peeling efficiency of the developer, reducing image density variations and preventing peeling failures by allowing the developer to undergo two peeling steps, thereby maintaining image quality and device size.
Implementation Method 1
A magnet for two-component development is fixedly arranged inside the developing sleeve. The magnet has a plurality of magnetic poles and causes a surface of the developing sleeve to carry the two-component developer.
Implementation Method 2
In the developer subjected to development and having a decreased toner density, a repulsive magnetic field is formed between magnetic poles of the same polarity of the magnet.
Data Source
AI summary
A groove is provided in a magnet such that a first magnetic force region where an absolute value of a magnetic force of a component in a direction normal to a developer carrying member is 1 [nN] or less is formed on a surface of the developer carrying member on a downstream side of a third maximum peak position and on an upstream side of a second maximum peak position in a rotation direction of the developer carrying member, and a second magnetic force region where the absolute value of the magnetic force of the component in the direction normal to the developer carrying member is 1 [nN] or less is formed on the surface of the developer carrying member on a downstream side of a first maximum peak position and on an upstream side of the third maximum peak position in the rotation direction of the developer carrying member.