Sheet Tray Auxiliary Pivot Mechanism for Sag Prevention
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Solution Overview
Problem
Existing sheet tray designs for image forming apparatuses face challenges in securely supporting and conveying sheets of varying lengths, leading to potential sagging and falling issues, especially when longer sheets are used.
Innovation Solution
The design incorporates a manual feed tray with a pivotally mounted auxiliary tray system, featuring a lift plate and extension plate with inclined surfaces, which guides and supports the sheet to prevent sagging and ensure stable conveyance by creating a sagging shape that keeps the sheet securely in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple flat tray design is used, then the device complexity is reduced, but sheets of varying lengths cannot be securely supported and may sag or fall
Solution Approach 1:
The tray is divided into a main body and an auxiliary tray that can be pivotally mounted. The auxiliary tray includes a lift plate and extension plate that can be independently positioned to provide segmented support points along the sheet length, enabling secure support for sheets of varying lengths while maintaining a relatively simple overall structure.
Solution Approach 2:
The auxiliary tray is configured to create a sagging shape (curvature in the vertical dimension) rather than providing flat support. This dimensional change allows the tray to accommodate and support sheets of varying lengths by creating a curved support surface that matches the natural sag of longer sheets, preventing them from falling while adding minimal structural complexity.
2Adaptability or versatility
If the auxiliary tray is extended to support longer sheets, then sheet support capability is improved, but the device complexity increases
Solution Approach 1:
The auxiliary tray is pivotally mounted to the main body, allowing it to be dynamically adjusted between different positions. This dynamic configuration enables the auxiliary tray to adapt to sheets of varying lengths by pivoting to the appropriate angle, providing versatile sheet length accommodation while keeping the mechanism simple and avoiding complex fixed structures.
Solution Approach 2:
The auxiliary tray can be positioned to nest within or alongside the main body structure when not in use, and extends outward when needed to support longer sheets. This nesting approach allows the extended functionality to be integrated into the existing device footprint, increasing adaptability without proportionally increasing overall device complexity.
3Reliability
If the lift plate is positioned higher to prevent sheet sagging, then sheet support stability is improved, but the sheet conveyance smoothness deteriorates due to potential sheet catching
Solution Approach 1:
The lift plate and extension plate are positioned at specific local points rather than uniformly across the entire tray. The lift plate provides localized upward support at the sheet leading end, while the extension plate provides localized support further along the sheet. This distributed local quality approach prevents sheet sagging at critical points while maintaining smooth conveyance by avoiding excessive height that would catch the sheet.
Solution Approach 2:
The auxiliary tray components are configured to create a gradual sagging shape (curvature) rather than sharp angular supports. This curved geometry allows the sheet to follow a smooth path over the support points, preventing catching and obstruction while still providing sufficient support stability to prevent sagging and falling of longer sheets.
Data Source
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AI summary
A sheet tray (46A) includes a tray section (7). A rear end portion of the tray section (7) capable of supporting an upstream side of a sheet in a direction of conveyance of the sheet extends in a width direction of the sheet transversely of the direction of conveyance of the sheet. Both ends of the rear end portion of the tray section (7) in the width direction of the sheet are raised upward perpendicularly to a placement surface relative to the middle of the rear end portion in the width direction of the sheet.