Developing Device Sealing Member with Projected Portions
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Solution Overview
Problem
Existing developing devices with seals that are either too small or too large for the gap between the development blade and roller lead to toner leakage, as they either leave gaps or lift the blade, respectively, causing developer to leak from the device.
Innovation Solution
A developing device with a sealing member at each end of the frame, contacted to the roller, and a development blade with a free edge downstream relative to its base, featuring projected portions between the roller and sealing member to prevent toner leakage, ensuring a secure fit regardless of assembly inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is made larger than the wedge-shaped gap between the development blade and development roller, then the sealing coverage is improved, but the seal lifts the development blade, creating gaps and allowing toner leakage
Solution Approach 1:
The seal is designed with non-uniform thickness, being thicker at certain locations to fill larger gaps and thinner at other locations to avoid lifting the blade. This local variation in seal thickness allows different regions of the seal to perform different functions: some regions provide enhanced sealing while other regions maintain blade contact stability.
Solution Approach 2:
The seal is made of elastic material that can dynamically adjust its shape and thickness in response to the wedge-shaped gap between the development blade and roller. The elastic properties allow the seal to compress and deform, maintaining optimal contact pressure without lifting the blade, thereby adapting to assembly variations.
2Ease of operation
If a seal is made smaller than the wedge-shaped gap between the development blade and development roller, then the blade contact is maintained, but gaps remain between the seal and development components, allowing toner leakage
Solution Approach 1:
The seal is designed with non-uniform thickness, being thicker at certain locations to fill larger gaps and thinner at other locations to avoid lifting the blade. This local variation in seal thickness allows different regions of the seal to perform different functions: some regions provide enhanced sealing while other regions maintain blade contact stability.
Solution Approach 2:
The seal is made of elastic material that can dynamically adjust its shape and thickness in response to the wedge-shaped gap between the development blade and roller. The elastic properties allow the seal to compress and deform, maintaining optimal contact pressure without lifting the blade, thereby adapting to assembly variations.
3Ease of manufacture
If the seal shape does not perfectly match the wedge-shaped gap, then assembly is simplified, but toner leakage occurs due to mismatched sealing surfaces
Solution Approach 1:
Instead of requiring the seal to perfectly match the wedge-shaped gap in terms of geometry, the seal's elastic properties are utilized to change its shape during assembly and operation. The elastic seal can deform to conform to the wedge-shaped gap, achieving effective sealing without requiring complex matching between seal and gap geometries.
Solution Approach 2:
The seal is designed with non-uniform thickness, being thicker at certain locations to fill larger gaps and thinner at other locations to avoid lifting the blade. This local variation in seal thickness allows different regions of the seal to perform different functions: some regions provide enhanced sealing while other regions maintain blade contact stability.
Data Source
AI summary
A developing apparatus includes a frame supporting the developing roller; a sealing member provided at each of one and the other ends of the developing device frame and contacted to the developing roller to prevent leakage of the developer; and a developing blade contacted to the developing roller to regulate an amount of the developer carried on the developing roller, the developing blade having a free end in a downstream side with respect to a rotational moving direction of the developing roller, wherein each of one and the other ends of the developing blade is provided with a projected portion projecting in the rotational axis direction between the developing roller and the sealing member.