Developing Roller Coupling for Precise Compact Process Cartridges
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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 allows direct rotational driving force input to the developing roller independently from the photosensitive drum, using 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 to transmit rotational driving force with permitted axis deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
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 introduces a shaft coupling member as an intermediary component between the drive transmission member and the developing roller. This coupling member includes a coupling portion that can be engaged with the drive transmission member, allowing direct force transmission while accommodating misalignment. The intermediary coupling mechanism eliminates the need for idler gears and provides both space savings and improved rotational accuracy through direct coupling.
Solution Approach 2:
The shaft coupling member is designed with movable and rotatable capabilities, allowing it to dynamically adjust its position and orientation. The coupling portion can move in the axial direction and rotate, enabling the system to adapt to misalignment between the drive transmission member and developing roller axes. This dynamic adjustment ensures smooth engagement and maintains rotational accuracy while reducing the space required.
2Ease of operation
If the photosensitive drum and developing roller are spaced apart, then maintenance is easier, but engagement between drive transmission member and developing roller becomes difficult
Solution Approach 1:
The shaft coupling member is designed with movable and rotatable capabilities, allowing it to dynamically adjust its position and orientation. The coupling portion can move in the axial direction and rotate, enabling the system to adapt to misalignment between the drive transmission member and developing roller axes. This dynamic adjustment ensures smooth engagement and maintains rotational accuracy while reducing the space required.
Solution Approach 2:
The engagement structure is designed so that the shaft coupling member can be preliminarily positioned and engaged with the drive transmission member before the developing roller is fully installed. This preliminary engagement action simplifies the overall mounting process, allowing the drive connection to be established independently of the developing roller's final position, thereby facilitating easier maintenance operations.
3Manufacturing precision
If direct rotational driving force input to developing roller is implemented, then rotational accuracy is improved, but the structure becomes more complex
Solution Approach 1:
The shaft coupling member is designed with movable and rotatable capabilities, allowing it to dynamically adjust its position and orientation. The coupling portion can move in the axial direction and rotate, enabling the system to adapt to misalignment between the drive transmission member and developing roller axes. This dynamic adjustment ensures smooth engagement and maintains rotational accuracy while reducing the space required.
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
This solution enhances the rotational accuracy of the developing roller, improves image quality, and allows for a more compact design of the process cartridge and image forming apparatus, while maintaining easy mounting and operation.
Implementation Method 1
utilizing an Oldham coupling to transmit rotational driving force with permitted axis deviation
Implementation Method 2
The engaging portion is movable in a direction crossing with the axial direction of the developing roller. When the process cartridge enters the main assembly of the apparatus with the developing unit positioned in the spaced position, an axis of the engaging portion is deviated from the axis of the developing roller with respect to the crossing direction.
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.