Developing Device Sealing Mechanism for Toner Leakage Prevention
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Solution Overview
Problem
Conventional image forming apparatuses face difficulties in sealing the supply roller assembly effectively, leading to toner leakage when the developing device is attached, which results in dot stains on the printed surface.
Innovation Solution
The developing device incorporates a film-shaped sealing member that contacts the developing roller and extends along its longitudinal direction, combined with a restricting section in the case to prevent movement of the holding member, ensuring secure attachment and preventing toner leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing members are arranged to contact with both ends of the supply roller assembly, then sealing performance is improved, but the supply roller assembly still leaks toner due to insufficient sealing force
Solution Approach 1:
The sealing solution is divided into multiple segments: first sealing members at both ends of the supply roller assembly, a second sealing member (film) extending along the longitudinal direction, and a third sealing member at the lower surface. This segmented approach distributes the sealing force across multiple locations and orientations, preventing toner leakage more effectively than a single sealing point.
Solution Approach 2:
The sealing structure transitions from one-dimensional (end seals only) to two-dimensional coverage by adding a film-shaped second sealing member that extends along the longitudinal direction of the supply roller assembly. This dimensional expansion creates a broader sealing barrier that prevents toner leakage along the entire length of the assembly.
2Ease of operation
If the supply roller assembly is attached to the developing device, then the developing device can function, but toner leaks from the supply roller assembly ends
Solution Approach 1:
The sealing members are pre-installed and positioned on the supply roller assembly before it is attached to the developing device. The first sealing members are attached to both ends, the second sealing member (film) is stretched across the longitudinal direction, and the third sealing member is positioned at the lower surface. This preliminary sealing configuration ensures that when the assembly is attached and pressurized during operation, toner cannot leak through pre-identified weak points.
3Reliability
If sealing force is increased to prevent toner leakage, then sealing performance improves, but the structure becomes more complex
Solution Approach 1:
The film-shaped second sealing member serves multiple functions simultaneously: it provides sealing along the longitudinal direction, acts as a barrier against toner leakage, and can be integrated with the existing supply roller assembly structure. This multi-functionality reduces the need for additional separate sealing components, maintaining structural simplicity while enhancing sealing capability.
Data Source
AI summary
A developing device includes an image supporting member; a developer supporting member for attaching developer to a latent image formed on a surface of the image supporting member for developing; a supply member for supplying developer to the developer supporting member; a first sealing member arranged to contact with both ends of the developer supporting member and the supply member; a holding member for holding the first sealing member; a case for attaching the developer supporting member and the supply member; a second sealing member arranged in the case for contacting with a lower surface of the developer supporting member in a longitudinal direction thereof when the developer supporting member is attached to the case. Further, a restricting section is provided in the case for restricting a movement of the holding member when the developer supporting member is attached to the case.