Sheet Feeder Friction-Member Structure for Warped Sheets
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Solution Overview
Problem
Existing sheet feeders struggle to prevent stacked multi-sheet feeding and misfeeds when dealing with deformed sheets, such as those warped by moisture, while maintaining a compact size.
Innovation Solution
The sheet feeder incorporates a supply tray with a first and second support surface and a friction member, where the second surface is positioned upstream in the feed direction, allowing the friction member to reliably contact the bottom surface of the lowermost sheet, even when deformed, while minimizing height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the friction member protrudes more than the document placement portion to contact the bottom surface of the lowermost sheet, then the friction member can reliably contact the lowermost sheet to suppress stacked multi-sheet feed, but the upper limit position of the pickup roller must be raised by the height of the protrusion, increasing the device height
Solution Approach 1:
The friction member is configured with a two-level structure where the first surface (protruding portion) contacts the bottom surface of the lowermost sheet, and the second surface (lower portion) is positioned upstream in the feed direction. This spatial arrangement in multiple dimensions allows the friction member to effectively contact deformed sheets without requiring excessive protrusion height, thereby suppressing stacked multi-sheet feed while maintaining compact device height.
2Adaptability or versatility
If sheets are supported in a stacked state on the document placement portion, then multiple sheets can be fed, but deformed sheets (warping due to moisture) cannot be properly contacted by the friction member, leading to stacked multi-sheet feed
Solution Approach 1:
The friction member is divided into two distinct surfaces: a first surface (protruding portion) that contacts the bottom surface of the lowermost sheet to apply frictional force, and a second surface (lower portion) positioned upstream in the feed direction. This segmentation allows each surface to perform its specific function - the first surface suppresses stacked multi-sheet feed by contacting the lowermost sheet even when deformed, while the second surface provides additional support and stability for stacked sheets.
3Shape
If a pressing force is applied to correct deformed sheets, then sheet deformation may be reduced, but it is still difficult for the friction member to contact the bottom surface of the lowermost sheet
Solution Approach 1:
The friction member's first surface (protruding portion) is positioned to preemptively contact the bottom surface of the lowermost sheet before the pickup roller feeds the uppermost sheet. This preliminary contact ensures that the friction member is already in position to apply frictional force and prevent stacked multi-sheet feed, even when sheets are deformed and pressing force has not yet corrected their shape.
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
This configuration effectively suppresses stacked multi-sheet feeding and misfeeds, ensuring reliable sheet feeding and reducing the device's height compared to conventional designs.
Implementation Method 1
The friction member contacts a bottom surface of the lowermost sheet supported by the document placement portion and applies a frictional force to the lowermost sheet
Data Source
AI summary
A supply tray includes a first tray and a second tray. The first tray forms a first support surface including a downstream end of a sheet support surface in a feed direction. The second tray forms a second support surface adjacent to the first support surface from upstream in the feed direction. A friction member includes a first surface and a second surface. The first surface is provided to face a feed roller. The second surface is provided upstream of the first surface in the feed direction. The first surface is located farther from a rotation axis than the second support surface and the second surface are in a first direction which is parallel to a perpendicular line as viewed in a width direction. The perpendicular line is drawn from the rotation axis to the first surface in a state where the feed roller contacts the first surface.