Developing Roller Shaft Counterweight Design for Stable Rotation
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Solution Overview
Problem
In image forming apparatuses, the developing roller shaft is inclined due to uneven weight distribution caused by the developing roller driving gear, leading to unstable rotation and inefficient developer supply to the photosensitive drum.
Innovation Solution
The developing roller shaft is designed with a small diameter part at one end and a larger diameter part at the other, with the developing gear fixed to the small diameter end, offsetting the weight increase and preventing axial inclination, allowing stable rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the developing roller driving gear is attached to one end portion of the developing roller shaft, then the developing roller can be driven to rotate, but the weight distribution becomes uneven causing the shaft to incline and rotate unstably
Solution Approach 1:
A counterweight portion is formed on the developing roller shaft at a position opposite to where the driving gear is attached. This counterweight portion has a volume and density designed to compensate for the weight of the driving gear, creating a balanced weight distribution that prevents shaft inclination and ensures stable rotation during operation.
Solution Approach 2:
The developing roller shaft is designed with non-uniform local properties: the counterweight portion has different volume and density characteristics compared to other portions of the shaft. This local variation in quality allows the shaft to achieve overall weight balance while maintaining the necessary structural integrity and driving capability at the gear attachment point.
2Ease of manufacture
If the developing roller shaft is made uniform in diameter, then manufacturing is simpler, but weight balance cannot be achieved when gear is attached
Solution Approach 1:
The developing roller shaft transitions from a uniform diameter design to one with varying local dimensions. The counterweight portion is formed with a larger volume than other portions of the shaft, creating the necessary weight imbalance compensation. This local quality variation achieves weight balance while remaining compatible with standard manufacturing processes.
Data Source
AI summary
A developing cartridge includes: a housing having first and second sidewalls through which respective end portions of a developing roller shaft are rotatably inserted; a developing gear, which is arranged outside of the first sidewall, and which is fixed to the end portion of the developing roller shaft; a transmission gear, which is arranged outside of the first sidewall, and which transmits driving force to the developing gear; a first cover member, which is attached to the first sidewall, and which covers the transmission gear; and a second cover member, which is attached to the first sidewall, and which covers the developing gear from an outer side in the axis line direction. The second cover member is formed separately from the first cover member and is arranged side by side with the first cover member outside of the first sidewall.