Roller Member Snap Fit Retention for Sheet Feeder
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Solution Overview
Problem
Conventional roller members with removably mounted roller parts on a rotary shaft suffer from displacement and rattling issues, leading to sheet misfeed in image forming apparatuses, and require cumbersome replacement processes, increasing costs and complexity.
Innovation Solution
A roller member design featuring a snap fit portion with an engagement protrusion that elastically deforms to engage with an engagement recess on the rotary shaft, using an elastic restoring force to securely position and retain the roller part, preventing displacement and facilitating easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the roller part is removably mounted on the rotary shaft by engaging a snap fit claw with a groove, then the roller part can be replaced individually when deteriorated, but a gap is produced between the snap fit claw and the groove leading to rattling and sheet misfeed
Solution Approach 1:
The roller part is divided into a roller body and a core material, with the snap fit claw integrated into the core material. This segmentation allows the roller part to be removably mounted on the rotary shaft while maintaining structural integrity, enabling individual replacement of the roller part when deteriorated without replacing the entire roller body.
Solution Approach 2:
The snap fit claw is extracted as a separate functional element from the roller body and integrated into the core material. This extraction allows the snap fit claw to engage with the groove on the rotary shaft, providing secure mounting while enabling easy removal and replacement of the roller part.
2Reliability
If a guide cover is added to control the axial rattling of the roller part, then the roller part displacement is prevented, but the number of parts increases and the apparatus grows in size
Solution Approach 1:
The positioning retention part is merged with the rotary shaft as an integrated structure rather than a separate component. The engagement recess is formed directly on the rotary shaft, combining the functions of the rotary shaft and the guide cover into a single element, thereby preventing rattling without increasing the number of parts.
Solution Approach 2:
The rotary shaft is designed with dual functionality: it rotates to drive the roller part and simultaneously features an engagement recess that acts as a positioning retention part to prevent axial rattling. This multi-functionality eliminates the need for separate guide covers or positioning mechanisms.
3Ease of repair
If the guide cover is made rotatable for separation and mounting operations, then the roller part can be replaced, but the replacement operation becomes cumbersome and time-consuming
Solution Approach 1:
The snap fit claw is extracted and integrated into the core material, allowing the roller part to be simply pulled off the rotary shaft by overcoming the snap fit engagement. This eliminates the need for rotatable guide covers or complex release mechanisms, reducing replacement time and operational complexity.
Solution Approach 2:
The roller part is designed as a disposable or easily replaceable component with a simple snap fit mounting structure. The engagement and disengagement require minimal effort, allowing quick replacement without time-consuming operations, similar to disposable components that are designed for rapid installation and removal.
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
The solution effectively prevents roller part displacement and rattling during sheet feeding, ensuring proper sheet transport and reducing the complexity and cost of replacement by maintaining the roller part in a predetermined position on the rotary shaft.
Implementation Method 1
the snap fit portion which is extended axially outward from the other end of the roller part and includes an engagement protrusion for engagement with the engagement recess, brings the engagement protrusion into engagement with the engagement recess as elastically deformed in a direction opposite to its extension direction
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In a roller member where a rotary shaft (110) is inserted through a through-hole (111) of a roller part so that the roller part is removably mounted on the rotary shaft, the rotary shaft is provided with a positioning retention part (121) for retaining one end of the roller part. Further, the rotary shaft is provided with an engagement recess (123) at place on its portion outward of the other end of the roller part. An engagement protrusion (117) is provided at a snap fit portion (116) extended axially outward from the other end of the roller part. In a state where the snap fit portion is elastically deformed in a direction opposite to the extension direction, the engagement protrusion is engaged with the engagement recess.