Developing Device Roller Gap Scraping Mechanism
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Solution Overview
Problem
The existing developing devices in laser printers face issues with toner leakage due to the small particle size of the developer, which can escape through gaps between the roller and the case, leading to staining of external devices and reduced toner fluidity at the longitudinal ends of the developing sleeve.
Innovation Solution
A gap is created between the end surface of the roller main body and the inner surface of the case main body, with a fixed member that rotates and scrapes off the developer entering this gap, preventing it from reaching the inner surface and reducing leakage by ensuring the developer does not remain in the gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the case main body is sealed airtight, then developer leakage is prevented, but developer may still leak through gaps between the roller and case inner surface
Solution Approach 1:
The patent extracts and removes the developer that accumulates in the gap between the roller end surface and case inner surface using a scraping mechanism. This prevents the extracted developer from remaining in the gap and potentially leaking, thereby addressing the harmful effect while maintaining the sealed structure.
Solution Approach 2:
The patent introduces a scraping mechanism as an intermediary element between the roller and case inner surface. This intermediary actively removes developer from the gap, preventing direct leakage from the sealed case while managing the harmful effect of accumulated developer.
2Device complexity
If developer is allowed to remain in the gap, then sealing structure is simple, but toner fluidity deteriorates and leakage occurs
Solution Approach 1:
The rotating roller itself serves the dual function of both carrying developer and enabling its removal through the scraping mechanism. The roller's rotation drives the scraping action, allowing the system to self-regulate developer removal without requiring an external power source or complex control system.
3Object-affected harmful factors
If a scraping mechanism is added to remove developer from the gap, then developer leakage is prevented, but device complexity increases
Solution Approach 1:
The patent merges the scraping function with the existing roller structure. The scraping mechanism is integrated into the roller assembly, combining multiple functions (developer transport and developer removal) into a unified structure, thereby reducing overall device complexity while achieving leakage prevention.
Solution Approach 2:
The roller assembly is designed to perform multiple functions: it carries developer during rotation and simultaneously enables developer removal through the integrated scraping mechanism. This multi-functionality reduces the need for separate components, thereby managing device complexity while preventing leakage.
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 effectively suppresses toner leakage by ensuring the developer is scraped off before it can escape, maintaining toner fluidity and preventing accumulation that could lead to leakage.
Implementation Method 1
The fixed member rotates and scrapes off the developer entering this gap
Data Source
AI summary
A developing device is provided that includes a developer containing case that contains a developer. The developer containing case includes a case main body and a supply roller that is rotatably supported on the case main body. The supply roller has a rotary shaft, a cylindrical roller main body that covers the rotary shaft, and a fixed member that is fixed to at least one of the rotary shaft and the roller main body. A gap is provided between an end surface of the roller main body and an inner surface of the case main body, and the fixed member partially occupies the gap.