Sheet Feeder Separation Arm Guide Member Curling Prevention
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Solution Overview
Problem
Existing sheet feeders face challenges in preventing multiple-sheet feeding and curling of leading ends when feeding highly stacked, easily-bendable sheets, due to issues with frictional resistance and positional accuracy between the separation roller and separation arm.
Innovation Solution
A sheet feeder configuration that includes a separation roller and a separation arm with a guide member having a low-friction surface, where the guide member extends to contact the separation roller and guide sheets along its surface, creating a wedge shape to prevent curling and ensure single-sheet feeding by applying varying frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the leading end of the film is extended close to the nipping point between the feed roller and the discrimination arm, then the reformation of the sheet into a curled shape is prevented, but an operation of separating sheets cannot be achieved and multiple-sheet feeding occurs
Solution Approach 1:
The discrimination arm is divided into two distinct functional zones: a low-friction film region (first region) that guides the sheet leading end and prevents curling, and a high-friction surface region (second region) that separates sheets by applying frictional resistance. This segmentation allows each region to perform its specific function without interfering with the other, solving the contradiction between preventing sheet curling and achieving sheet separation.
2Ease of operation
If the film is short and the leading end is far from the nipping point, then the sheet leading end cannot establish sliding contact with the film at a small angle, but the upstream-side portion of the sheet is forced to be fed and reformed in a curled shape
Solution Approach 1:
The low-friction film acts as an intermediary element between the sheet leading end and the high-friction discrimination arm surface. It provides a smooth transition zone that reduces frictional resistance during the initial contact and guidance phase, allowing the sheet to be fed smoothly into position without being forced to reform into a curled shape.
3Reliability
If a high-friction discrimination arm is used to separate sheets, then sheet separation is achieved, but easily-bendable sheets stacked high experience great resistance and curling at the leading end
Solution Approach 1:
Different regions of the discrimination arm are given different frictional properties: the first region (low-friction film) provides minimal resistance for guiding the sheet leading end and preventing curling, while the second region (high-friction surface) provides strong frictional resistance for separating sheets. This local differentiation of properties allows the system to achieve both sheet separation and prevention of leading end curling simultaneously.
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 prevents multiple-sheet feeding and curling of sheets, allowing for smooth, sequential feeding of highly stacked, easily-bendable sheets by controlling frictional resistance and guiding sheets along the separation roller's surface.
Implementation Method 1
a guide member (25) having a guide portion (25c) with a lower-friction surface than the separation arm (23)
Implementation Method 2
the separation arm (23) adapted to apply higher frictional resistance to the one or more second sheets (9) than that to the first sheet (9) near the nipping point
Data Source
AI summary
A sheet feeder includes a separation roller having a circumferential surface that contacts a first sheet to be fed first among stacked sheets and picks up the first sheet and one or more second sheets adjacent to the first sheet, a separation arm that is closer to the circumferential surface of the separation roller downstream in a feeding direction and configured to apply higher frictional resistance to the second sheets than the first sheet to feed the first sheet ahead of the second sheets, and a guide member including a guide portion that has a lower-friction surface than the separation arm and extends from the separation arm with a distal end thereof in contact with or close to the circumferential surface of the separation roller. The guide portion guides the first and second sheets along the circumferential surface of the separation roller.