Process Cartridge Coupling for Accurate Developing Roller Drive
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face challenges in downsizing and improving image quality due to the rotational accuracy issues of the developing roller, which are influenced by the engagement of the input gear, idler gear, and main assembly gear, leading to space constraints and reduced precision.
Innovation Solution
The implementation of a process cartridge with a shaft coupling member that directly inputs rotational driving force to the developing roller independently from the photosensitive drum, allowing for smooth engagement and improved rotational accuracy by using an Oldham coupling to transmit rotational driving force with permitted axis deviation, enabling the developing roller to be spaced from the photosensitive drum during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the input gear is provided on a fixed swing center and driving force is transmitted through idler gears, then the conventional structure is simple, but the developing roller requires more space and rotational accuracy is reduced
Solution Approach 1:
The patent extracts the idler gear from the drive transmission system, directly connecting the input gear to the developing roller. This eliminates the intermediate transmission component, reducing the space required for the developing roller assembly while simplifying the overall drive mechanism structure.
Solution Approach 2:
The patent segments the drive transmission function by providing the input gear on the swing center of the developing unit, allowing independent rotation and direct power transmission to the developing roller without requiring a fixed common swing center for the entire system.
2Manufacturing precision
If driving force is transmitted through input gear, idler gear, and main assembly gear, then the conventional structure is established, but rotational accuracy of the developing roller is influenced by engagement variations
Solution Approach 1:
The patent removes the idler gear from the transmission path, creating a direct drive connection between the input gear and developing roller. This eliminates cumulative engagement errors that would occur through multiple gear interfaces, significantly improving rotational accuracy while reducing mechanical complexity.
Solution Approach 2:
The patent designs the input gear to be rotatably provided on the swing center, allowing preliminary positioning and smooth engagement before the developing unit swings into its working position. This ensures accurate rotational alignment is established before operation begins.
3Ease of operation
If the developing unit is spaced from the photosensitive drum during mounting, then mounting smoothness is improved, but the shaft coupling must accommodate axis deviation
Solution Approach 1:
The patent employs a shaft coupling mechanism that dynamically adapts to axis deviation between the photosensitive drum and developing roller. The coupling allows the developing unit to be spaced during mounting, and automatically aligns the rotational axes when the unit swings into its working position, facilitating smooth operation.
Solution Approach 2:
The shaft coupling acts as an intermediary element between the photosensitive drum and developing roller, accommodating misalignment and axis deviation. This mediator enables the developing unit to be mounted in a spaced position while ensuring proper rotational connection during operation.
Data Source
AI summary
A process cartridge comprises a photosensitive drum and a developing roller. A coupling member is provided adjacent to one axial end of the developing roller. The coupling member includes a driven portion, and an intermediary portion configured and positioned to engage with the driven portion. The intermediary portion is also configured to be movable relative to the driven portion in a direction crossing the axis of the developing roller while maintaining engagement with the driven portion. The coupling member further includes a driving portion configured and positioned to receive a driving force for rotating the developing roller. The driving portion is also configured to engage with the intermediary portion, and to be movable relative to the intermediary portion in a direction crossing the axis of the developing roller while maintaining engagement with the intermediary portion.