Sheet Feeding Apparatus Pullback Rollers Double Feed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sheet feeding apparatuses face inefficiencies due to insufficient reverse conveying force when pulling back double-fed overlapping sheets, leading to reduced operating rates and potential paper jams, especially when handling varying sheet sizes and attachments like sticky notes.
Innovation Solution
A sheet feeding apparatus with a pair of pullback rollers disposed symmetrically outside the feed roller, driven to provide a sufficient reverse conveying force by rotating in the opposite direction upon double-feed detection, ensuring effective retraction of overlapping sheets to the stacking tray.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the retard roller is rotated in reverse direction to pull back double-fed originals, then the double-fed originals can be retracted toward the sheet supply tray, but the conveying force may be limited by the torque transmitting member and sufficient reverse conveying force cannot be obtained
Solution Approach 1:
The patent combines the functions of the feed roller and retard roller into a single roller that can rotate in both directions. This merged roller integrates the feeding function (normal rotation) and the pullback function (reverse rotation), eliminating the need for separate feed and retard rollers and their associated torque transmitting members that limited reverse conveying force.
Solution Approach 2:
The patent applies reverse rotation of the combined roller to achieve the pullback function. By rotating the same roller that feeds originals in the normal direction in the opposite direction, the system retrieves double-fed originals without requiring a separate mechanism, thereby obtaining sufficient reverse conveying force.
2Reliability
If the scanner stops operating temporarily each time double feed occurs, then the double feed can be detected and handled, but the operating rate is reduced and working efficiency significantly decreases
Solution Approach 1:
The patent implements automatic pullback functionality where the system itself retrieves double-fed originals without operator intervention. The combined roller automatically rotates in reverse to pull back double-fed sheets, and the control unit automatically resumes feeding after successful pullback, enabling the system to handle double feeds autonomously and maintain continuous operation.
Solution Approach 2:
The patent uses a double feed detection sensor to provide feedback about double feed occurrences. When the sensor detects double-fed originals, the control unit receives this feedback and automatically activates the pullback function. After pullback is complete, the system receives feedback that the issue is resolved and automatically resumes normal feeding, creating a closed-loop control system that maintains high operating rates.
3Ease of operation
If a torque limiter or spring clutch is used as torque transmitting member in the retard roller, then the roller can allow certain torque in reverse direction, but the conveying force is limited and sufficient reverse conveying force cannot be obtained
Solution Approach 1:
The patent removes the torque transmitting member (torque limiter or spring clutch) from the system by eliminating the separate retard roller. The combined roller that replaces it can rotate freely in both directions without torque transmission limitations, extracting the problematic torque-limiting component while maintaining the necessary reverse rotation capability for pullback operations.
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 apparatus achieves reliable retraction of double-fed sheets, preventing image loss and paper jams, while maintaining processing efficiency even with mixed sheet sizes and attachments, by ensuring a sufficient conveying force is applied during the reverse feeding operation.
Implementation Method 1
a pair of pullback rollers disposed symmetrically outside the feed roller... driven to provide a sufficient reverse conveying force by rotating in the opposite direction... ensuring effective retraction of overlapping sheets
Data Source
AI summary
A sheet feeding apparatus capable of obtaining a sufficient conveying force for pulling back double-fed overlapping sheets to a stacking tray side. A sheet feeding member feeds sheets incoming from a stacking tray which stacks the sheets into a conveying pass. A separating member separates the sheets fed to the conveying pass by the sheet feeding member one by one. A double feed detection sensor generates an output for detecting double feed of sheets fed to the conveying pass. A rotatable member contacts the fed sheet. A driving unit rotationally drives at least the rotatable member in a rotational direction for reverse feeding of sheets. A control unit controls the driving unit when the double feed of sheets is detected based on the output of the double feed detection sensor, such that the rotatable member is rotationally driven in the rotational direction for reverse feeding of sheets.