Sheet Feeder Control for Thin Paper Jam Prevention
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Solution Overview
Problem
Conventional sheet feeders experience jam issues when feeding thin paper or similar low-stiffness materials due to catching by the feed roller, despite existing jam mitigation techniques.
Innovation Solution
A sheet feeder control method that adjusts the timing and pressure of the pickup roller's contact with the sheet, using sensors to detect the sheet's leading and trailing edges, and varying the feeding speed of the feed roller to prevent jamming, particularly for thin paper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pickup roller is moved to contact the sheet and rotated to feed the sheet, then the sheet can be conveyed, but thin paper with low stiffness may be caught by the feed roller causing jam
Solution Approach 1:
The pickup roller is moved to the sheet take-in position and brought into contact with the sheet before rotation begins. This preliminary positioning ensures the sheet is properly engaged with the pickup roller surface, allowing for controlled feeding without catching on the feed roller. The roller remains in contact with the sheet during the waiting period after the preceding sheet passes the pre-registration sensor, preparing the sheet for smooth conveyance.
Solution Approach 2:
The pickup roller's operation is made dynamic through conditional control based on sensor detection. The roller waits at the sheet take-in position for a predetermined time after the pre-registration sensor detects the trailing edge of the preceding sheet, then rotates only if no new sheet is detected. This dynamic adjustment of timing and rotation based on real-time sheet presence detection prevents thin paper from being caught by the feed roller while maintaining effective sheet feeding capability.
2Reliability
If the pickup roller waits at the sheet take-in position for a predetermined time, then thin paper jam is reduced, but feeding speed may be reduced
Solution Approach 1:
The pickup roller operates in periodic cycles: waiting at the sheet take-in position for a predetermined time after sensor detection, then rotating to feed the sheet, then returning to the initial position. This periodic operation with built-in waiting periods allows thin paper to be properly positioned and fed without catching, while maintaining continuous feeding capability for multiple sheets through the cycle-based operation.
Solution Approach 2:
The system uses feedback from the pre-registration sensor to control the pickup roller timing. The sensor detects the trailing edge of the preceding sheet, triggering the pickup roller to wait for a predetermined time before rotating. This feedback-based timing adjustment ensures the roller is ready to feed the next sheet without catching thin paper, optimizing both reliability and feeding speed through sensor-driven control.
Data Source
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AI summary
[Problem] To make jam less likely to occur in feeding even if a sheet to be fed is thin paper or the like with low stiffness. [Solution] In a case where starting feeding of a subsequent sheet by a feed roller (6) after reaching of the trailing edge of a preceding sheet is detected by a post-registration sensor (34) (S210), a control unit (45) of a sheet feeder (101) controls the feed roller (6) to rotate at a first feeding speed (V3) (low speed) (S202), and in a case where the leading edge of the subsequent sheet has passed through a nip position between the feed roller (6) and a separation roller (7) (YES in step S203), the control unit (45) controls the feed roller (6) to rotate at a second feeding speed (V4) (high speed) (S204).