Sheet Conveyance Apparatus with Projected Portions for Sagging Prevention
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Solution Overview
Problem
Existing sheet conveyance systems, particularly in image forming apparatuses, face challenges in preventing sheet sagging during reverse conveyance, especially when the discharge direction is horizontal, as they rely solely on the stiffness imparted by wave-shape forming units, which is insufficient.
Innovation Solution
A sheet conveyance apparatus with a reverse conveyance portion, a supporting portion, and an opposing portion, where the supporting and opposing portions have projected elements that protrude and overlap, providing additional stiffness to the sheet by deforming it in a convex shape, thereby preventing sagging and improving alignment and conveyance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only wave-shape forming unit is used to prevent sheet sagging, then the structure remains simple, but sheet sagging prevention is insufficient especially in horizontal discharge direction
Solution Approach 1:
The sheet conveyance path is segmented into multiple zones: the wave-shape forming unit creates initial curvature, while the supporting portion and opposing portion with projected portions create additional localized support zones. This segmentation allows each component to contribute specifically to preventing sheet sagging without requiring a complete redesign of the entire conveyance system.
Solution Approach 2:
The invention adds a vertical dimension to sheet support by introducing projected portions that extend toward each other in the sheet thickness direction. This creates a three-dimensional support structure that physically prevents the sheet from sagging downward, complementing the two-dimensional wave-shape forming approach.
2Manufacturing precision
If wave-shape forming unit is used to impart stiffness to sheet, then some alignment improvement is achieved, but conveyance resistance and skewing are not sufficiently reduced
Solution Approach 1:
The invention modifies the physical parameters of the sheet by creating convex deformation through the interacting projected portions. This changes the sheet's stiffness parameter and structural integrity, enabling it to resist conveyance resistance and skewing forces more effectively while maintaining proper alignment.
Solution Approach 2:
The projected portions create a convex curved shape in the sheet, which distributes mechanical stresses more evenly during conveyance. This curvature prevents the sheet from flattening or skewing under conveyance forces, reducing both conveyance resistance and directional deviation.
3Area of stationary object
If sheet is conveyed in horizontal direction, then discharge space is optimized, but sheet sagging increases due to gravity
Solution Approach 1:
The supporting portion and opposing portion with projected portions create an upward support force that counteracts the downward gravitational force on the horizontal sheet. This anti-weight mechanism prevents sagging without requiring vertical discharge orientation, maintaining optimized discharge space while improving sheet stability.
Data Source
AI summary
A sheet conveyance apparatus includes a reverse conveyance portion and a second conveyance direction, a supporting portion configured to support a lower surface of the sheet conveyed by the reverse conveyance portion, and an opposing portion provided along and above the supporting portion. Either one of the supporting portion and the opposing portion includes a first projected portion. The other of the supporting portion and the opposing portion includes a second projected portion and a third projected portion. The first projected portion is arranged between the second projected portion and the third projected portion in a width direction intersecting with the first conveyance direction. At least a part of the first projected portion is arranged to overlap with the second projected portion and the third projected portion in a sheet thickness direction.