Cylindrical Shaft Restriction for Sheet Conveyance Accuracy
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Solution Overview
Problem
The existing sheet conveyance devices in image forming apparatuses face issues with the sliding properties due to gaps or stepped portions in hollow metal shafts, which affect the rotation and contact between components, leading to potential damage and reduced accuracy in sheet conveyance.
Innovation Solution
A sheet conveyance device is designed with a cylindrical metal shaft and a restriction member that restricts the shaft's movement in the width direction and rotation, using a cap and torsion spring to prevent sliding and ensure accurate alignment and rotation, thereby preventing contact between the shaft and other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a hollow metal shaft is used to reduce weight and material cost, then the weight and cost are reduced, but gaps or stepped portions are formed that deteriorate sliding properties
Solution Approach 1:
A restriction member is introduced as an intermediary component between the hollow metal shaft and the surrounding structure. This restriction member fills the gap or covers the stepped portion at the joint of the hollow shaft, preventing direct contact and sliding between the shaft ends and other components, thereby resolving the sliding property issue while maintaining the lightweight hollow shaft structure
Solution Approach 2:
The restriction member is specifically positioned only at the critical location where the gap or stepped portion exists in the hollow shaft, rather than modifying the entire shaft structure. This localized approach prevents sliding at the problematic area while maintaining the overall lightweight design and minimal interference with other functions
2Ease of manufacture
If a hollow metal shaft is used to reduce weight and material cost, then the material cost is reduced, but gaps or stepped portions are formed that affect rotation accuracy
Solution Approach 1:
The restriction member acts as a mediator that compensates for the positional inaccuracies inherent in hollow shaft manufacturing. By providing a reference surface and physical constraint, it ensures accurate positioning and rotation even when the hollow shaft itself has manufacturing tolerances, thereby maintaining rotation accuracy without requiring expensive precision manufacturing
3Reliability
If the hollow metal shaft is prevented from sliding, then sliding is prevented, but additional components are required increasing device complexity
Solution Approach 1:
The restriction member is designed as a simple intermediary component that can be integrated into the existing structure with minimal additional elements. It provides sliding prevention through its geometric constraint and contact surfaces, achieving reliable sliding prevention without requiring complex mechanisms, multiple components, or complicated assembly procedures
Data Source
AI summary
A sheet conveyance device includes a driving rotation device, a driven rotation device, and a supporting device including first and second restriction surfaces and supporting the driven rotation device. The driving rotation device rotates by receiving rotational driving force and drives the driven rotation device to rotate at a position facing the driving rotation device. The driven rotation device includes a driven rotation member contacting the driving rotation device, a cylindrical shaft having a cylindrical shape that rotatably supports the driven rotation member, and a restriction member that is at least partially inserted in an inner circumference side of the cylindrical shaft. A position of the cylindrical shaft is restricted in a width direction crossing the sheet conveyance direction by the restriction member contacting the first restriction surface, and movement of the cylindrical shaft in a rotational direction is restricted by the restriction member contacting the second restriction surface.