Developing Device Rotary Gear Support and Alignment
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Solution Overview
Problem
The existing developing devices for image forming apparatuses face challenges in maintaining compact size due to protrusion of the drive input gear beyond the casing, leading to unstable rotation and displacement issues, which compromise the efficiency and stability of the rotary shafts.
Innovation Solution
A developing device design that includes a rotary gear with a rotary shaft parallel to the rotary body's shaft, supported by a stationary shaft member fixed to the casing, ensuring the drive input gear is securely rotated and does not protrude, with the axial center of the stationary shaft member being collinear with the rotary shaft, preventing displacement and maintaining compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drive input gear is disposed outside the lateral wall of the casing to facilitate torque transmission, then the torque transmission efficiency is improved, but the compact size of the developing device is compromised due to protrusion
Solution Approach 1:
The drive input gear is nested within the casing by extending the rotary shaft outwardly through the lateral wall, allowing the gear to be positioned inside the casing boundaries while still receiving torque from the external drive source. This nesting approach eliminates protrusion and maintains compact dimensions.
Solution Approach 2:
The rotary shaft is extended in the axial direction (perpendicular to the lateral wall) to position the drive input gear inside the casing. By utilizing the axial dimension for shaft extension rather than radial positioning, the gear can transmit torque effectively while remaining within the casing boundaries, thus maintaining compact size.
2Power
If the rotary shaft is extended outwardly through the lateral wall to support the drive input gear, then the gear can be positioned for effective torque transmission, but displacement of the rotary shaft occurs due to play in the rotary bodies
Solution Approach 1:
A bearing is introduced as an intermediary component between the extended rotary shaft and the casing. This bearing mediates the connection by supporting the rotary shaft and eliminating play, thereby preventing displacement while allowing the shaft to extend outwardly for effective gear positioning and torque transmission.
Solution Approach 2:
The bearing is installed in advance to cushion and absorb the play in the rotary shaft before operation begins. This pre-cushioning prevents displacement issues during operation, ensuring stable positioning of the drive input gear while maintaining the extended shaft configuration for effective torque transmission.
3Device complexity
If the drive input gear is used as one of the drive gears of the rotary bodies, then the number of components is reduced, but unstable rotation occurs due to displacement of the axial center of the rotary shaft
Solution Approach 1:
A bearing is introduced as an intermediary support mechanism for the rotary shaft that carries the drive input gear. This bearing eliminates play and prevents displacement of the axial center, ensuring stable rotation. The bearing allows the drive input gear to be integrated with the rotary body structure while maintaining rotational stability through proper support.
Data Source
AI summary
A developing device including a developer bearing member rotatable while bearing developer on a surface thereof, a rotary body having a rotary shaft, a casing that contains the developer supplied to the surface of the developer bearing member to accommodate at least a portion of the rotary body, a rotary gear having a rotary shaft parallel to the rotary shaft of the rotary body and disposed outside a lateral wall of the casing to support an end of the rotary shaft of the rotary body, and a stationary shaft member fixed to the lateral wall of the casing to rotatably support the rotary gear. An axial center of the stationary shaft member is collinear with an axial center of the rotary shaft of the rotary body.