Developing Device Seal Configuration for Toner Leakage Prevention
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Solution Overview
Problem
Existing developing devices in laser printers face issues with toner leakage due to developer entering the gap between the side seal member and the case main body, leading to soiling of external components.
Innovation Solution
A developing device design where the upstream end of the side seal member is positioned downstream of the contact area between the axis direction seal member and the developing roller, creating a gap between the axis direction seal member and the side seal member to prevent toner from entering and leaking out, utilizing a combination of axis direction and side seal members with specific seal configurations to enhance sealing efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side seal member is positioned to contact the axis direction seal member upstream of the contact area, then the sealing coverage is increased, but developer can enter between the side seal member and case main body causing leakage
Solution Approach 1:
The invention changes the positional relationship between seal members from the rotation direction to the axial direction. By positioning the upstream end of the side seal member downstream of the upstream end of the contact area between the axis direction seal member and developing roller, it creates an overlapping arrangement in the axial direction that prevents developer from entering the gap between the side seal member and case main body.
Solution Approach 2:
The axis direction seal member acts as an intermediary barrier that works in conjunction with the side seal member. The specific positioning ensures that the axis direction seal member's contact area with the developing roller is upstream of the side seal member's upstream end, creating a layered sealing structure where developer cannot penetrate through either seal member alone.
2Reliability
If the side seal member extends upstream to maximize sealing coverage, then more potential leakage paths are blocked, but developer can still enter between the side seal member and case main body
Solution Approach 1:
The invention applies different sealing strategies to different locations. The side seal member is positioned specifically downstream of the axis direction seal member's contact area, creating a localized overlapping sealing zone. This local quality approach ensures that the critical gap between the side seal member and case main body is protected without requiring the side seal member to extend unnecessarily upstream.
3Object-generated harmful factors
If the seal members are positioned to prevent developer entry, then leakage is reduced, but the configuration complexity increases
Solution Approach 1:
The sealing system is divided into two independent but coordinated segments: the axis direction seal member and the side seal member. Each seal member has a specific positioning function, with the side seal member's upstream end positioned downstream of the axis direction seal member's contact area. This segmentation allows for simplified individual component design while achieving effective sealing through their coordinated arrangement.
Data Source
AI summary
A developing device is provided with a case main body, a developing roller coupled with the case main body, an axis direction seal member coupled with the case main body, and a side seal member coupled with the case main body. The axis direction seal member and the side seal member make contact with one another such that there is no gap between the axis direction seal member and the side seal member in a rotation axis direction of the developing roller. In a rotation direction of the developing roller, an upstream end of the side seal member is located downstream of an upstream end of a contact area between the axis direction seal member and the developing roller.