Developing Unit Ventilation Opening and Filter for Pressure Control
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the internal pressure of the developing unit tends to rise due to factors like increased toner conveying speed and toner supply, leading to toner leakage through seals and filter clogging, which diminishes the ventilation effect and causes pressure buildup.
Innovation Solution
The implementation of a configuration that includes a ventilation opening and a filter member in the developing frame, with the ventilation opening disposed to reduce pressure and the filter allowing air passage while preventing toner leakage, and a developing unit design that adjusts the developing roller and filter position to enhance toner separation and ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speed of the toner conveying member is increased to supply more toner to the developing chamber, then the productivity is improved, but the internal pressure of the developing chamber increases causing toner leakage
Solution Approach 1:
The patent extracts the harmful factor (excessive internal pressure) from the system by introducing a ventilation opening that allows pressure relief. The ventilation opening is strategically positioned to vent excess pressure generated by high-speed toner conveyance, enabling sustained high productivity without toner leakage.
Solution Approach 2:
The patent introduces an intermediary element (ventilation opening with filter member) between the developing chamber interior and exterior. This intermediary allows pressure equalization while preventing direct toner escape, mediating between the need for high-speed toner supply and the need to prevent leakage.
2Productivity
If the thickness of the conveying unit is increased to supply more toner to the developing chamber, then the productivity is improved, but the internal pressure of the developing chamber increases causing toner leakage
Solution Approach 1:
The ventilation opening extracts excess pressure from the developing chamber, allowing thicker conveying units to be used for increased toner supply capacity without causing pressure buildup that would lead to leakage.
3Duration of action of stationary object
If the printer is used in a certain position for a long time, then the stability is improved, but toner adheres to the filter member causing it to clog and reduce ventilation capability
Solution Approach 1:
The patent applies dynamics by making the filter member rotatable relative to the ventilation opening. This rotational movement prevents toner from continuously contacting the same filter surface, thereby preventing clogging and maintaining ventilation capability over extended operational periods.
Solution Approach 2:
The rotatable filter member implements periodic action by continuously changing its position relative to the ventilation opening. This periodic movement ensures that no single area of the filter member is continuously exposed to toner, preventing accumulation and clogging over time.
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 internal pressure increases, reduces toner leakage, and maintains the ventilation capability of the developing chamber, ensuring stable operation and extended printer durability.
Implementation Method 1
a ventilation opening... disposed in a developing frame... to reduce pressure
Implementation Method 2
a filter member... allowing air passage while preventing toner leakage
Data Source
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AI summary
A unit includes: a conveying member that conveys developer; a frame that stores the developer and includes a first chamber storing the conveying member, a second chamber, a first opening connecting the first chamber and the second chamber, and through which the developer is passed, and a second opening connecting the interior of the second chamber and the exterior of the frame in an orthogonal direction that is orthogonal to a direction of a rotation axis line of the conveying member; and a filter that allows air to pass the second opening and restricts the developer from passing the second opening, and is fixed to the frame, wherein the frame is displaceable with respect to an apparatus main body in a state where the unit is attached to the apparatus main body, and the filter is displaced with respect to the apparatus main body by the displacement of the frame.