Half-Moon Sheet Feed Roller Layout for Longer Detectable Feed Distance
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Solution Overview
Problem
Existing sheet feeding devices with half-moon-shaped feed rollers face limitations in extending the feedable distance due to conflicts between the detectable distance and feedable distance, leading to potential feeding failures.
Innovation Solution
A sheet feeding device configuration that includes a movable sheet stacking tray, an eccentric cam, and a cam follower mechanism, allowing the sheet stacking tray to be positioned radially inward before contact with the feed roller, combined with a separation pad positioning mechanism that avoids reliance on pulleys, ensuring the feedable distance exceeds the detectable distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the sheet stacking tray is positioned closer to the feed roller to extend feedable distance, then the feedable distance is improved, but the detectable distance becomes insufficient leading to detection failures
Solution Approach 1:
The sheet stacking tray is made movable between a standby position (radially inward) and a feed position (contacting the feed roller) through cam-follower mechanisms. This dynamic positioning allows the system to optimize both states: during detection, the tray is retracted to maximize detectable distance; during feeding, the tray advances to maximize feedable distance, resolving the contradiction between these two distance requirements
Solution Approach 2:
The sheet stacking tray is positioned at a standby location radially inward of the feed roller's outer diameter before the feeding operation begins. This preliminary positioning ensures that the detectable distance is sufficient for reliable sheet detection, and then the tray is advanced to the feed position only when needed, allowing both detection and feeding to occur optimally in sequence
2Device complexity
If a half-moon-shaped feed roller is used to achieve compact design, then the device complexity is reduced, but the feedable distance is limited
Solution Approach 1:
The movable sheet stacking tray transforms the static half-moon feed roller system into a dynamic one. By allowing the tray to move between standby and feed positions, the effective feedable distance is extended without changing the compact half-moon roller design, thus maintaining design simplicity while improving feeding capability
Solution Approach 2:
Instead of extending the feed roller's radius or length to increase feedable distance, the solution adds movement in the radial dimension by positioning the tray at different radial locations (standby position inward, feed position outward). This dimensional approach extends feedable distance without compromising the compact design of the half-moon roller
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
The solution enables a longer feedable distance without detection failures, maintaining a compact design and preventing sheet feeding issues, enhancing user satisfaction by ensuring detected sheets are reliably fed.
Implementation Method 1
The eccentric cam 53 is fixed to a rotating shaft of the sheet feed roller 41 and has a maximum eccentric radius larger than the radius of the sheet feed roller 41. The cam follower 55 is provided at a position in the sheet stacking tray 27 where the cam follower 55 contacts the eccentric cam 53 and raises the sheet stacking tray 27 by moving the contact point from a large-diameter portion of the eccentric cam 53 to a small-diameter portion of the eccentric cam 53 as the eccentric cam 53 rotates.
Implementation Method 2
The sheet feed roller 41 is kept in pressed contact with the top surface of the sheet stacked on the sheet stacking tray 27 and has a half-moon-shaped feed surface that feeds out the sheet in a feed direction.
Implementation Method 3
The sheet detection mechanism includes a sheet detection sensor that includes a detection portion having a light emitting portion and a light receiving portion and a detection member that makes contact with the sheet stacked on the sheet stacking tray 27 to swing and that has a light-shielding portion that shields or opens the optical path of the detection portion.
Data Source
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AI summary
A sheet feeding device (26) has a sheet stacking tray (27), a sheet stop portion (39a), a sheet feed roller (41), a separation member (51), a first urging member (58), an eccentric cam (53), a cam follower (55), a sheet detection mechanism (57, 60), and a holding mechanism (70a, 71). The holding mechanism (70a, 71) holds the separation member (51) at a position away from the sheet feed roller (41) after a half-moon-shaped feed surface (41a) has passed across the separation member (51) as the sheet feed roller (41) rotates. Immediately before a sheet starts to be fed, the sheet stacking tray (27) is kept on standby at a standby position radially inward of the outer diameter of the feed surface (41a) so that the feedable distance (d2) between the feed start position (P3) and the sheet stop portion (39a) is larger than the detectable distance (d1) as the maximum distance between the detectable position (P1) at which the sheet can be detected by the sheet detection mechanism (57, 60) and the sheet stop portion (39a).