Developing Device Blade Fixation for Toner Leakage Prevention
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Solution Overview
Problem
The existing developing device experiences leakage of the developing agent due to reduced contacting pressure between the blade unit and the developing roller at the position adjacent to the inner end of the side seal member, leading to inefficiencies in toner regulation and image formation.
Innovation Solution
The developing device is designed with a frame that positions the support surface of the fixing portion for the blade unit inward of the inner edge of the side seal member, ensuring sufficient contacting pressure between the blade unit and the developing roller, and incorporating a seal member to prevent toner leakage, with the support surface's outer edge positioned outward of the side seal member's inner edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the support surface is positioned outward of the inner edge of the side seal member, then the blade unit can be fixed outside the seal member, but the contacting pressure between the blade unit and the developing roller is reduced at the portion adjacent to the inner end of the side seal member, causing leakage of the developing agent
Solution Approach 1:
The support surface is designed with non-uniform pressure distribution, concentrating the contacting pressure at specific locations (at least one position) adjacent to the side seal member while allowing other areas to have reduced pressure. This localized pressure application prevents developing agent leakage at critical areas without requiring high overall pressure across the entire blade unit, thus resolving the contradiction between ease of fixation and leakage prevention.
2Device complexity
If the support surface is positioned outward of the inner edge of the side seal member, then the blade unit structure is simplified, but the gap between the longitudinal end portion of the developing roller and the blade allows toner leakage
Solution Approach 1:
The blade unit is designed to apply concentrated contacting pressure at specific localized positions adjacent to the side seal member rather than distributing pressure uniformly. This creates effective sealing at the gap between the developing roller end and blade, preventing toner leakage while maintaining a simple overall blade unit structure that can be easily fixed to the frame.
3Ease of operation
If the contacting pressure is reduced at the portion adjacent to the inner end of the side seal member, then the blade unit can be easily positioned, but the leakage of the developing agent occurs through the gap between the longitudinal end portion of the developing roller and the blade
Solution Approach 1:
The support surface is configured to provide concentrated contacting pressure at at least one specific position adjacent to the side seal member, creating localized high-pressure zones that seal the gap between the developing roller and blade. This allows the blade unit to be easily positioned overall while ensuring reliable sealing at the critical leakage-prone areas through localized pressure application.
Data Source
AI summary
A developing device includes a frame, a developing roller, a blade unit, and a first seal member. A blade unit extends in an axial direction of the developing roller and in contact with the peripheral surface thereof. The first seal member is configured to seal a boundary between the frame and the axial end portions of the developing roller. The frame has a fixing portion to which end portions of the blade is fixed. The fixing portion has a support surface having an outer edge and an inner edge in the axial direction. The outer edge is positioned outward of an inner edge of the first seal member in the axial direction, and the inner edge of the support surface is positioned inward of the inner edge of the first seal member in the axial direction.