Drive Shaft Alignment in Image Forming Apparatus Cartridge
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Solution Overview
Problem
Image forming apparatuses face issues with relative displacement between drive shafts and driven shafts, leading to uneven rotation and image degradation due to accumulated dimensional tolerances, despite efforts to suppress such displacement through clearance and guiding mechanisms.
Innovation Solution
A support device and method that utilize a process cartridge with a cartridge-side fitting portion and an apparatus main body having a corresponding fitting portion, where the process cartridge is installed using the image carrier as a primary guide and the cartridge-side fitting portion as a secondary guide, ensuring proper alignment and connection between the drive shaft and driven shaft to maintain axial direction support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If clearance is provided between drive shaft and driven shaft to suppress relative displacement, then positional accuracy is improved, but device complexity increases
Solution Approach 1:
A positioning member is introduced as an intermediary component between the drive shaft and driven shaft. This positioning member includes a positioning protrusion that fits into a positioning groove, serving as a mediator to accurately define the relative position between the two shafts without requiring complex clearance adjustments or additional adjustment mechanisms.
Solution Approach 2:
The positioning member is pre-installed on the driven shaft before assembly with the drive shaft. The positioning groove is预先 formed on the positioning member, so that when the drive shaft is inserted, the positioning protrusion automatically engages with the positioning groove, preliminarily establishing the correct axial center alignment before final assembly completion.
2Ease of operation
If driven shaft is configured as primary guide member to guide process cartridge installation, then ease of operation is improved, but manufacturing precision deteriorates
Solution Approach 1:
The guidance function is transitioned from the axial dimension (driven shaft guiding) to the radial dimension (positioning protrusion fitting into positioning groove). The positioning protrusion extends radially from the drive shaft, and the positioning groove is formed radially on the positioning member, creating a radial guidance mechanism that is more precise than axial guidance.
Solution Approach 2:
The positioning member acts as a mediator that receives the drive shaft and guides its positioning. Instead of the driven shaft directly guiding the process cartridge installation, the positioning member with its positioning groove mediates the interaction, providing more accurate positional control while maintaining ease of installation through the simple fit-and-lock mechanism.
3Reliability
If relative displacement between drive shaft and driven shaft occurs, then rotational uniformity deteriorates, but image quality degradation increases
Solution Approach 1:
The mechanical clearance-based positioning system is replaced with a positive engagement positioning system. Instead of relying on clearance and friction to maintain positional relationship, the invention uses a positioning protrusion that mechanically engages with a positioning groove, providing deterministic and precise positional control that ensures uniform rotation.
Solution Approach 2:
The correct axial center alignment is preliminarily established by the positioning protrusion engaging with the positioning groove before the rotation process begins. This preliminary positioning action prevents relative displacement during operation, ensuring that the driven shaft rotates uniformly without the need for complex adjustment mechanisms during the rotation process.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A support device for use in an image forming apparatus includes a process cartridge (24) and an apparatus main body (10). The process cartridge (24) further includes an image carrier (14), at least one sub unit (15), and a cartridge-side fitting portion (38). The at least one sub unit (15) includes a rotational member (25) having a driven shaft (27). The apparatus main body (10) further includes an apparatus-main-body-side fitting portion (72) and a driving device (40). The driving device (40) is provided with a drive shaft (44), and is configured to drive the rotational member (25). With the support device, the drive shaft (44) is radially positioned at one support point along an axial direction thereof in the driving device (40) before installing the process cartridge (24) into the apparatus main body (10). In addition, the drive shaft (44) is radially positioned at the one support point and a connecting point between the driven shaft (25) and the drive shaft (44) after installing the process cartridge (14) into the apparatus main body (10).