Photosensitive Drum Positioning via Drive Gear Meshing
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Solution Overview
Problem
Conventional methods for positioning photosensitive drums in tandem-type color laser printers are complex, making it difficult to accurately align and mount multiple drums, which can lead to color shifts due to misalignment of rotating shafts.
Innovation Solution
An image forming apparatus with a simple structure that includes an outer frame, a photosensitive unit, a drum drive gear, a first positioning portion, and a second positioning portion, where the photosensitive unit has supporting shafts and a drum gear that are rotated by the drum drive gear to align with positioning slits in the outer frame, allowing for precise positioning without the need for springs or additional side plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional positioning methods using two side plates and springs are used, then photosensitive drums can be positioned, but the structure becomes complex and mounting becomes difficult
Solution Approach 1:
The patent removes the complex spring mechanism and one of the two side plates from the conventional positioning system. The drum drive gear itself is utilized to provide the positioning function, extracting unnecessary components while maintaining positioning capability through the meshing engagement between gears and the simplified side plate structure.
Solution Approach 2:
The drum drive gear serves dual functions: it drives the rotation of the photosensitive drums and simultaneously provides positioning functionality through its meshing engagement with the drum gears. This multi-functionality eliminates the need for separate positioning springs and complex mechanisms.
2Reliability
If conventional positioning methods with multiple side plates are used, then photosensitive drums can be supported, but mounting operation becomes difficult
Solution Approach 1:
The positioning function is segmented into two independent aspects: horizontal positioning through the side plate with positioning slit, and vertical positioning through the drum drive gear meshing with drum gears. This segmentation allows each component to perform its specific function independently, simplifying the overall mounting operation while maintaining stability.
Solution Approach 2:
The drum drive gear acts as an intermediary mechanism that translates the driving motion into both rotational motion of the drums and positioning action through its engagement with the drum gears. This intermediary function facilitates easy mounting while ensuring stable positioning.
3Manufacturing precision
If supporting shafts are inserted into accurately formed holes, then positioning accuracy is achieved, but concurrent insertion of multiple drums becomes difficult
Solution Approach 1:
The positioning system transitions from a static insertion method (shafts into fixed holes) to a dynamic positioning method where the drum drive gear's meshing engagement with the drum gears provides continuous positioning during rotation. This dynamic approach allows multiple drums to be positioned concurrently through the rotational motion and gear engagement.
Solution Approach 2:
The drum drive gear and drum gears automatically perform the positioning function through their meshing engagement during the driving process. The system self-positions the multiple drums concurrently without requiring manual alignment or complex insertion operations, as the gear engagement naturally maintains the required positional relationships.
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 enables easy mounting and accurate positioning of multiple photosensitive drums, reducing the risk of color shifts and simplifying the assembly process while maintaining stability and alignment.
Implementation Method 1
The drum drive gear is configured to apply a pushing force to the drum gear, the photosensitive drum, the first supporting shaft and the second supporting shaft in the second direction when the drum drive gear drives the drum gear.
Implementation Method 2
The drum drive gear is rotatably supported on the outer frame and is meshingly engaged with the drum gear to rotate the drum gear.
Data Source
AI summary
An image forming apparatus including an outer frame, a photosensitive unit, a drum drive gear, a first positioning portion, and a second positioning portion. The photosensitive unit includes a plurality of photosensitive drums, a first supporting shaft, a second supporting shaft, and a drum gear. Each of the plurality of photosensitive drums has an axis extending in a first direction. The plurality of photosensitive drums is juxtaposed in a second direction perpendicular to the first direction. A position of the first supporting shaft and the second supporting shaft provided on one of the plurality of photosensitive drums in the second direction with respect to the outer frame is determined by contacting the first supporting shaft and the second supporting shaft to the first positioning portion. A position of the two of the first supporting shafts and the two of the second supporting shafts in a third direction perpendicular to both the first direction and the second direction with respect to the outer frame is determined by supporting the two of the first supporting shafts and two of the second supporting shafts on the second supporting portion.