Developing Device Sealing Unit for Electrophotographic Roller Protection
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Solution Overview
Problem
Conventional sealing structures in electrophotographic developing devices fail to prevent developer leakage without damaging the developing roller, as they either allow leakage due to soft sealing materials or risk scratching the roller with rigid materials.
Innovation Solution
A sealing unit comprising a first and second sealing member, both preferably made of sponge, positioned between the blade and the housing, with a pressing member, such as a plate spring, to ensure no gaps and prevent leakage without damaging the developing roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft sealing member (sponge) is used to prevent developer leakage, then sealing effectiveness is improved, but gaps may form between the sealing member and blade causing leakage
Solution Approach 1:
The sealing member is divided into a first sealing member and a second sealing member positioned at different locations along the blade. The first sealing member seals the gap between the blade end and housing, while the second sealing member seals the gap between the blade and housing at another position. This segmentation allows each sealing member to be optimized for its specific location and function, preventing developer leakage through multiple sealing points.
2Reliability
If the attaching force of the sealing member to the blade is increased to prevent leakage, then sealing effectiveness is improved, but the blade may curve and fail to maintain constant thickness
Solution Approach 1:
A pressing member is introduced as an intermediary element between the sealing member and the blade. The pressing member applies controlled force to the sealing member, ensuring it maintains adequate attaching force to prevent developer leakage while preventing excessive force that would cause the blade to curve. This intermediary mechanism allows precise control over the sealing force applied to the blade.
3Stability of the object's composition
If rigid material is used for the blade ends to prevent curving, then blade stability is improved, but the rigid portions may scratch the developing roller surface
Solution Approach 1:
The blade is designed with different material properties at different locations. The main body of the blade maintains the necessary rigidity to prevent curving, while the end portions are designed with reduced rigidity or enhanced flexibility to prevent scratching the developing roller. This local differentiation of material properties allows the blade to simultaneously maintain overall stability and protect the roller surface at critical contact points.
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
Effectively seals the gap between the blade and the housing, preventing developer leakage while maintaining the integrity and longevity of the developing roller.
Implementation Method 1
a pressing member for pressing the first and second sealing members so as to prevent gaps between the first and second sealing members
Implementation Method 2
the sealing members 16 are generally formed of a sponge
Data Source
AI summary
A developing device has a sealing unit that seals a gap between an inner wall of a housing that stores developer and a blade that controls a thickness of developer attached on a developing roller. The sealing unit of the developing device includes a first sealing member inserted into a gap between the inner wall of the housing and an end portion of the blade, a second sealing member placed on the blade to contact the first sealing member, and a pressing member that presses the first and second sealing members so as to prevent gaps between the first and second sealing members. Therefore, the gap between the blade and the inner wall of the housing can be blocked efficiently without damaging the developing roller, and a stable and efficient developing process can be performed.