Developing Device Air Outlet for Toner Scattering Control
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Solution Overview
Problem
The existing electrophotographic image forming apparatuses face issues with toner scattering due to air pressure fluctuations in the developing chamber, leading to contamination of the photosensitive body and the printing medium, which degrades image quality and apparatus cleanliness.
Innovation Solution
Incorporating an air outlet connected to the developing chamber to regulate air pressure and reduce toner scattering, with a discharge path and valve system to control air flow and prevent excessive developer discharge, and strategically locating the air outlet to minimize contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If air inlet is used to supply air to the developing chamber, then air pressure is maintained for toner supply, but toner scatters with the air flow causing contamination
Solution Approach 1:
The air outlet is positioned at a different location than the air inlet, specifically at an upstream position in the rotation direction of the developing roller. This spatial segmentation separates the air discharge path from the toner supply path, allowing air to be discharged without carrying toner particles that would otherwise scatter with the air flow from the inlet.
Solution Approach 2:
The patent introduces an air outlet as an intermediary component that provides a dedicated discharge path for air to escape from the developing chamber. This intermediary structure allows air to be vented separately from the toner supply mechanism, preventing toner from being carried along with the air flow.
2Productivity
If printing speed is increased, then productivity is improved, but air pressure fluctuation increases causing more toner scattering
Solution Approach 1:
The air outlet provides a pressure relief mechanism that responds to air pressure fluctuations in real-time. When air pressure increases due to higher printing speeds, the air outlet allows excess air to escape, creating a feedback loop that stabilizes pressure and prevents toner scattering even at high productivity levels.
3Object-generated harmful factors
If air outlet is added to discharge air, then toner scattering is reduced, but device complexity increases
Solution Approach 1:
The air outlet is positioned at a specific local position within the developing chamber - at an upstream position in the rotation direction of the developing roller. This localized placement provides the necessary air discharge function without requiring a complete restructuring of the entire developing chamber, thus minimizing the increase in device complexity.
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
The solution effectively maintains internal pressure within the developing chamber, reducing toner scattering and contamination, thereby enhancing image quality and apparatus cleanliness, especially at higher printing speeds.
Implementation Method 1
Incorporating an air outlet connected to the developing chamber to regulate air pressure and reduce toner scattering
Implementation Method 2
with a discharge path and valve system to control air flow and prevent excessive developer discharge
Data Source
Figure 1~2
Figure 3
Figure 4~5c
AI summary
A developing device including a developing roller mounted in a developing chamber is provided. In the developing device, the developing roller is partially exposed to an environment outside the developing chamber through an opening portion of the developing chamber, an air inlet is provided between an upstream boundary of the opening portion in a rotational direction of the developing roller and an outercircumference of the developing roller, wherein air may pass into the developing chamber through the air inlet, and an air outletmay be formed near the upstream boundary of the opening portion and communicatively connected to the developing chamber so as to discharge the air in the developing chamber. The air outlet is located outside an effective image area in a length direction of the developing roller.