Photosensitive Drum Driving Mechanism Backlash Reduction
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Solution Overview
Problem
Existing image forming apparatuses with driving force transmission mechanisms for rotary bodies, such as photosensitive drums, have complex structures and high costs due to accumulated backlashes and elastic deformations, leading to inaccurate driving and increased expenses when using resin materials.
Innovation Solution
A simplified driving force transmitting mechanism where either the driven or driving section has a contact face part of a plane including the rotation axis, with the other section being a single boss parallel to the axis, reducing backlashes and elastic deformations by direct contact, thus allowing for accurate and cost-effective rotation of the rotary body at constant velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple members (pins, elongated holes, disc-like member) are interposed between the driving gear and the photosensitive drum, then accurate constant-angular-speed transmission can be achieved, but the structure becomes complicated and cost increases
Solution Approach 1:
The patent removes the intermediate disc-like member and pins from the driving mechanism, directly connecting the driving gear to the photosensitive drum. This extraction of unnecessary intermediate components simplifies the structure while maintaining accurate constant-speed transmission through a direct drive connection.
Solution Approach 2:
The patent merges the driving gear and photosensitive drum into a more integrated assembly where the driving gear directly engages with the drum without intermediate members. This combining of functions into a unified structure reduces complexity while preserving transmission accuracy.
2Force
If multiple members are interposed between the driving gear and the photosensitive drum, then force transmission can be distributed, but backlashes accumulate at multiple positions
Solution Approach 1:
The patent eliminates the intermediate pins and disc-like member that caused multiple backlash positions, creating a direct force transmission path from the driving gear to the photosensitive drum. This removes the sources of accumulated backlashes while maintaining effective force transmission.
3Ease of manufacture
If resin materials are used for the intermediate members, then manufacturing cost is reduced, but elastic deformation and inclination occur
Solution Approach 1:
The patent removes the resin intermediate members that caused elastic deformation, replacing them with a direct metal-to-metal connection between the driving gear and photosensitive drum. This eliminates the elastic deformation problem while keeping the overall design simple and cost-effective.
Data Source
AI summary
An image forming apparatus includes a developing unit, a transfer unit, and a photosensitive drum assembly. The drum assembly has a photosensitive drum, a driven section integral with the photosensitive drum, and a driving section which transmits a driving force to the driven section to rotate the photosensitive drum. Either one of the driven section and the driving section comprises a contact face, which constitutes a part of a plane including a rotation axis of the photosensitive drum. The other of the driven section and the driving section comprises a single boss, which is substantially in parallel with the rotation axis and contacts the contact face.