Developing Roller Coupling for Precise Cartridge Drive Alignment
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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 introduction of a shaft coupling member that allows direct rotational driving force input to the developing roller independently from the photosensitive drum, with a movable engaging portion that deviates from the developing roller's axis, enabling smooth engagement with the main assembly drive transmission member even when the photosensitive drum and developing roller are spaced apart, and utilizing an Oldham coupling for precise rotational force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the input gear is provided on a swing center that does not change in position, then the structure is simple, but the developing roller requires more space and rotational accuracy is influenced by gear engagement
Solution Approach 1:
The patent introduces a shaft coupling member as an intermediary component between the main assembly drive transmission member and the developing roller. This coupling member includes a movable engaging portion that can adjust its position, serving as a mediator that decouples the direct gear engagement relationship. The shaft coupling member transmits rotational force while allowing for positional adjustments, thereby improving rotational accuracy without requiring complex positioning mechanisms.
Solution Approach 2:
The engaging portion of the shaft coupling member is designed to be movable in a direction crossing the axial direction of the developing roller. This dynamic capability allows the engaging portion to automatically adjust its position during the mounting process and during operation, ensuring optimal engagement with the main assembly drive transmission member regardless of minor misalignments or spacing variations between the photosensitive drum and developing roller.
2Ease of operation
If the photosensitive drum and developing roller are spaced apart, then the structure allows for maintenance and replacement, but the engaging portion must align precisely with the drive transmission member
Solution Approach 1:
The movable engaging portion of the shaft coupling member can adjust its position dynamically during the mounting process. When the process cartridge is installed, the engaging portion automatically positions itself to engage with the main assembly drive transmission member, regardless of the spacing between the photosensitive drum and developing roller. This eliminates the need for precise pre-alignment while maintaining reliable drive transmission.
Solution Approach 2:
The shaft coupling member with its movable engaging portion performs self-alignment during the mounting process. The engaging portion automatically finds its correct position relative to the main assembly drive transmission member without requiring external adjustment or precise positioning of the photosensitive drum and developing roller. This self-aligning capability simplifies the mounting process while ensuring reliable engagement.
3Manufacturing precision
If direct rotational driving force is input to the developing roller independently from the photosensitive drum, then rotational accuracy is improved, but a new drive transmission mechanism is required
Solution Approach 1:
The shaft coupling member serves multiple functions: it acts as a drive transmission component, a positioning mechanism, and a spacing compensator. By providing a movable engaging portion, the same basic structure can accommodate different spacing conditions while maintaining reliable drive transmission. This multi-functionality reduces the need for additional specialized components.
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.