Developing Device Air Guide Suppresses Toner Scattering
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Solution Overview
Problem
Existing image forming apparatuses face issues with toner scattering due to air entering the developing device, leading to pressure increases and toner being blown out, which can contaminate functional components like the charger.
Innovation Solution
A developing device with a housing, developing roller, gap forming member, and guide section is designed, where the gap forming member creates a first gap between itself and the developing roller and a second gap between itself and the housing, with the guide section directing air currents to prevent toner from escaping, maintaining a specific interval ratio to ensure effective air circulation and minimize toner scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If air enters the developing device according to rotation of the developing roller, then air circulation is achieved, but pressure in the developing device rises causing toner to blow out and scatter
Solution Approach 1:
The developing device is divided into multiple sealed chambers (first developing chamber, second developing chamber, third developing chamber) with controlled air circulation paths. Each chamber has specific openings and guide sections that segment the air flow, allowing air to circulate within defined boundaries while preventing uncontrolled toner scattering. The gap forming member further segments the space between the developing roller and housing to control air flow patterns.
Solution Approach 2:
The guide section acts as an intermediary element that directs air flow from the second gap through the upstream side opening to the first gap. This intermediary structure controls the air current path, ensuring that air circulation occurs without creating high pressure zones that would cause toner to blow out. The guide section mediates between the air circulation requirement and the toner containment requirement.
2Loss of energy
If pressure in the developing device rises, then air circulation is maintained, but functional components such as charger are likely to be stained
Solution Approach 1:
The device is segmented into multiple sealed chambers that isolate the developing process from other functional components. The charger and other components are positioned in separate zones that are not directly exposed to high-pressure air flows from the developing roller. This spatial segmentation prevents toner-laden air from reaching and staining the charger.
Solution Approach 2:
The guide section and housing structure serve as intermediary barriers between the developing chamber and the charger. These intermediaries redirect air flows away from sensitive components, ensuring that even when pressure rises in the developing chamber, the contaminated air current does not reach the charger, thus preventing staining while maintaining air circulation.
3Loss of energy
If gap forming member creates first gap and second gap, then air flow control is improved, but device complexity increases
Solution Approach 1:
The gap forming member serves multiple functions simultaneously: it creates the first gap between itself and the developing roller for controlled air flow, creates the second gap between itself and the housing for additional air circulation control, and acts as a structural support element. The housing also serves multiple roles including containing the developing chamber, guiding air flows, and positioning other components. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The guide section is integrated into the housing structure rather than being a separate component, merging the air guidance function with the housing's structural and containment functions. The gap forming member is positioned to simultaneously create both the first gap and second gap, combining multiple air flow control functions into a single component arrangement, thus managing complexity while achieving effective air flow control.
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 scattering, reducing the risk of contamination and eliminating the need for additional components like filters, thus improving maintainability and preventing image defects.
Implementation Method 1
The developing roller performs development by a developer carried by a magnetic force of the development pole
Implementation Method 2
The guide section directs an air current discharged from the second gap via the upstream side opening to the first gap
Data Source
AI summary
A developing device according to an embodiment includes a housing, a developing roller, a gap forming member, and a guide section. The gap forming member forms a first gap between the gap forming member and the developing roller. The gap forming member forms a second gap between the gap forming member and the housing. The second gap includes an upstream side opening on a rotating direction upstream side of the developing roller. The guide section directs an air current discharged from the second gap via the upstream side opening to the first gap. A relation of H1/H2<5 is satisfied, where H1 is a minimum interval between the developing roller and the gap forming member in the first gap and H2 is a minimum interval between the housing and the gap forming member in the second gap when viewed from an axial direction of the developing roller.