Developing Roller Gap Coverage for Pressure and Leakage Balance
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Solution Overview
Problem
Existing developing devices experience an increase in internal pressure and developer leakage due to the complete coverage of the gap between the developing member and the housing with a covering member.
Innovation Solution
A developing device design that partially covers the gap between the developing member and the housing, leaving an open region to manage internal pressure and strategically positions covering members to minimize leakage, using a combination of cover films and seals to control developer flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the entire gap between the developing member and housing is covered with a covering member, then developer leakage is suppressed, but internal pressure of the housing increases
Solution Approach 1:
The covering member is divided into a first covering portion and a second covering portion that are positioned at different locations in the gap. The first covering portion covers a first region corresponding to one end portion of the developing member, while the second covering portion covers a second region corresponding to the other end portion. This segmentation allows selective coverage of gap regions to suppress developer leakage at critical locations while leaving other regions open to relieve internal pressure.
Solution Approach 2:
Different regions of the gap are treated differently: some regions are covered with the covering member to prevent developer leakage, while other regions are left uncovered to allow pressure relief. The covering member is strategically positioned to cover only specific regions where developer leakage is most likely to occur, rather than covering the entire gap uniformly.
2Object-generated harmful factors
If the entire gap is covered with a covering member, then developer leakage is prevented, but material usage increases and assembly becomes more complex
Solution Approach 1:
The covering member is segmented into multiple portions (first covering portion and second covering portion) that can be independently positioned and assembled. This segmentation simplifies the assembly process compared to installing a single large covering member, while still providing effective leakage prevention at critical regions.
Solution Approach 2:
Instead of covering the entire gap with a covering member, only specific regions (first region and second region corresponding to end portions of the developing member) are covered. This partial coverage approach reduces material usage and simplifies assembly while still effectively preventing developer leakage where it is most likely to occur.
Data Source
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AI summary
A developing device includes: a housing that accommodates a developer and that has an opening facing an image holding body capable of holding a latent image; a developing member that is rotatably provided in the housing, that is exposed from the opening, that is capable of holding the developer on an outer periphery of the developing member, and that develops the latent image with the held developer while rotating; and a covering member that covers a gap between the developing member and the housing downstream of a development position of the developing member in a rotation direction, that covers a first region in the gap corresponding to one end portion of the developing member in a rotation axis direction, and that does not cover at least a part of an intermediate region in the gap corresponding to a region between both end portions of the developing member in the rotation axis direction.