Developing Apparatus Bearing Seal Design
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Solution Overview
Problem
In developing apparatuses using two-component developers, the space between the bearing and magnet often fills up with developer particles that slip through the magnetic seal, leading to premature melting and solidification, which can cause the shaft and bearing to weld together, necessitating frequent maintenance and reducing the device's service life.
Innovation Solution
A developing apparatus design that includes a bearing accommodating portion with a first space between the magnet and bearing, and a second space in fluid communication with the first space, allowing developer particles that slip past the magnetic seal to accumulate and be directed into a developer holding portion, preventing the space between the bearing and magnet from filling up and reducing the risk of the shaft and bearing welding together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic seal is provided between the housing and bearing to prevent developer leakage, then developer leakage is reduced, but developer particles still slip through and accumulate in the space between the bearing and magnet, causing the space to fill up prematurely
Solution Approach 1:
The bearing accommodating portion is divided into a first space (between magnet and bearing) and a second space (outside the bearing in radial direction), allowing developer particles to be directed to a designated accumulation area rather than filling the critical first space
Solution Approach 2:
A developer guiding portion is introduced as an intermediary structure that directs developer particles from the first space to the second space, preventing accumulation in the critical bearing-magnet interface area
2Device complexity
If the space between bearing and magnet is small to prevent developer accumulation, then the structure is compact, but the bearing is heated by friction and melts the developer, causing the shaft and bearing to weld together
Solution Approach 1:
The developer accumulation function is extracted from the first space (between bearing and magnet) and relocated to the second space (outside the bearing), eliminating the harmful accumulation effect while maintaining the compact first space structure
Solution Approach 2:
Different regions of the bearing accommodating portion are assigned different functions: the first space maintains compact dimensions for structural integrity, while the second space provides developer accumulation capacity, with a guiding portion directing particles between regions
3Reliability
If the magnetic seal is made stronger to prevent developer slippage, then developer leakage is reduced, but the friction heat increases, melting the developer and causing welding between shaft and bearing
Solution Approach 1:
The developer particles that slip through the magnetic seal (a harmful effect) are redirected to accumulate in the second space, converting them from a harmful accumulation source into a controlled, designated storage area that protects the bearing system
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 design effectively prevents the space between the bearing and magnet from filling with developer particles, reducing the likelihood of the shaft and bearing welding together, thus extending the service life of the developing device and lowering maintenance costs by allowing developer particles to accumulate in a designated area rather than causing operational issues.
Implementation Method 1
a magnet, provided around said shaft at a position inside said bearing in said bearing accommodating portion, for forming a magnetic seal of magnetic particles by a magnetic field formed between itself and said shaft
Data Source
AI summary
A developing apparatus includes a developing container for accommodating a developer including magnetic particles; a developer feeding member, provided in the developing container and having a magnetic shaft, for feeding the developer; a bearing rotatably supporting the shaft; a bearing accommodating portion; and a magnet, provided around the shaft at a position inside the bearing in the bearing accommodating portion, for forming a magnetic seal of magnetic particles by a magnetic field formed between itself and the shaft. The bearing accommodating portion includes a first space between the magnet and the bearing and a second space which is provided outside of the bearing with respect to a diametrical direction and which is in fluid communication with the first space to receive the developer from the first space.