Bushing Assembly Axial Positioning Developer Roll Replacement
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Solution Overview
Problem
Existing electrophotographic image forming devices face challenges in manufacturing complexity and compact component design, particularly in the replaceable units of rotatable imaging components like developer rolls, which require efficient axial and rotational alignment without increasing device size.
Innovation Solution
A bushing assembly with a separable design that includes a cylindrical opening and a groove on the outer surface, allowing for rotatable support of the shaft and axial positioning relative to the housing, facilitating easy installation and replacement of the developer roll while minimizing space and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a replaceable unit construction is used for rotatable imaging components, then ease of replacement is improved, but device complexity increases
Solution Approach 1:
The developer roll assembly is divided into separable components: the developer roll itself, the bushing, and the housing. The bushing is further segmented with distinct features (cylindrical opening, groove, outer surface) that enable independent functions. This segmentation allows the developer roll to be easily replaced while keeping the housing and other components, reducing replacement complexity.
Solution Approach 2:
The bushing is extracted as a separate, removable component from the housing. By taking out the bushing with its specific mating features, the design enables the developer roll to be independently replaced without removing the entire housing or other components, thus improving ease of replacement while minimizing added complexity.
2Volume of moving object
If compact components are used, then device size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The bushing incorporates local quality variations through its distinct features: the cylindrical opening with specific inner circumferential surface, the circumferential groove at a specific axial position, and the outer surface with mating features. Each feature is optimized for its specific function (rotational support, axial positioning, engagement with housing), allowing compact dimensions while maintaining adequate manufacturing precision for each localized function.
Solution Approach 2:
The bushing utilizes multiple dimensions to achieve compactness: the cylindrical opening provides rotational support in the radial dimension, the groove provides axial positioning in the axial dimension, and the mating features on the outer surface provide engagement in both radial and axial dimensions. This multi-dimensional approach allows compact component size while distributing precision requirements across different dimensions and features.
3Volume of moving object
If axial and rotational alignment is provided without increasing device size, then compactness is improved, but alignment precision may be compromised
Solution Approach 1:
The bushing merges multiple alignment functions into a single compact component: the cylindrical opening simultaneously provides rotational support and rotational alignment, the groove provides axial positioning, and the mating features on the outer surface provide both radial and axial alignment with the housing. This merging of functions into one component achieves precise alignment without requiring multiple separate alignment features that would increase device size.
Solution Approach 2:
The bushing acts as an intermediary component between the developer roll shaft and the housing. It mediates the alignment relationship by providing the cylindrical opening that rotatably supports the shaft (ensuring rotational alignment) and the groove that engages with the housing (ensuring axial alignment). This intermediary bushing achieves precise alignment in both dimensions while maintaining a compact form factor.
Data Source
AI summary
An assembly for an electrophotographic image forming device includes a housing and a rotatable component. A bushing has an opening defined by an inner circumferential surface of the bushing. A shaft of the rotatable component is received in the opening such that the inner circumferential surface rotatably supports the shaft. A first mating feature is positioned on an outer surface of the bushing that is opposite the inner circumferential surface of the bushing. The first mating feature is positioned between an inner axial end of the bushing and an outer axial end of the bushing relative to a rotational axis of the rotatable component. The first mating feature of the bushing is in contact with a second mating feature on the housing. Contact between the first and second mating features defines an axial position of the bushing relative to the housing along the rotational axis of the rotatable component.