Drive Unit Housing for Image Formers with Encoder Protection
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Solution Overview
Problem
Existing drive units for image forming apparatuses face issues with foreign matter adhesion on encoders and sensors, poor assembly operability, and tilt of the output shaft due to inadequate housing design, leading to precision and cost challenges.
Innovation Solution
A drive unit design where the velocity reduction gear and detection mechanism are housed together with the output shaft supported by a housing body and support plate, featuring an encoder attachment bracket that prevents foreign matter adhesion and allows adjustable sensor positioning for precise rotation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the velocity detection mechanism is attached directly to the drive output shaft and drive roller outside of a unit without being protected with a housing, then the setting space and assembly operability are poor, but the structure is simple
Solution Approach 1:
The patent combines the velocity reduction mechanism and velocity detection mechanism into a single integrated housing unit. This merging approach protects both mechanisms from foreign matter while maintaining a compact structure that does not significantly increase overall device complexity.
Solution Approach 2:
The velocity detection mechanism is nested within the housing that also contains the velocity reduction mechanism. This nesting arrangement provides protection from foreign matter while utilizing the same spatial envelope, avoiding significant increases in device complexity.
2Reliability
If the velocity reduction mechanism is separated from the velocity detection mechanism with support bearings on a partition wall, then foreign matter protection is improved, but the intervals between support bearings are short causing output shaft tilt
Solution Approach 1:
The patent merges the velocity reduction mechanism and velocity detection mechanism into the same housing space rather than separating them with a partition wall. This eliminates the problem of short bearing intervals and output shaft tilt while still providing foreign matter protection through the enclosed housing structure.
3Ease of operation
If the housing is separated into a first member and a second member, then assembly operability is improved, but molding precision and alignment precision requirements increase
Solution Approach 1:
The housing is divided into a first housing member and a second housing member that can be assembled separately. This segmentation improves assembly operability while the design ensures that molding precision and alignment precision requirements remain manageable through proper feature design.
4Device complexity
If the encoder and sensor are fixed without adjustment capability, then the structure is simple, but abrasion of the encoder occurs when members rotate in contact
Solution Approach 1:
The patent makes the sensor assembly adjustable along the shaft direction, transforming a fixed structure into a dynamic one that can be positioned to prevent contact between the encoder and sensor during operation. This eliminates encoder abrasion while adding minimal complexity through simple adjustment capability.
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 configuration prevents foreign matter adhesion, enhances assembly and miniaturization, reduces space requirements, and improves precision and cost-effectiveness by allowing for easier adjustment and maintenance of the drive unit, thereby ensuring high-precision rotation control.
Implementation Method 1
a velocity detection mechanism including an encoder and a sensor member for detecting a revolution of the output shaft
Data Source
AI summary
A drive unit includes a motor being a drive source, a velocity reduction gear for reducing the revolution of the motor, an output shaft for connecting the velocity reduction gear to the rotation shaft of a photosensitive drum, and a velocity detection mechanism including an encoder and sensor members and detecting the revolution of the output shaft. The velocity reduction gear and the velocity detection mechanism are placed in a unit housing including a housing body made of a resin with one end opened and a support plate made of metal closing the opening of the housing body, and the output shaft is rotatably supported by the housing body and the support plate.