Sheet Conveying Device with Preliminary Feeding Control
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Solution Overview
Problem
Existing sheet conveying devices face challenges in minimizing the distance between sheets and preventing sheet jams, particularly when there are variations in sheet lengths, as they rely on detecting the trailing end of a sheet before feeding the next one, which can lead to inefficiencies and jams if the trailing end is not detected in time.
Innovation Solution
A sheet conveying device that calculates the length of each sheet and controls the sheet feed timing to start feeding the next sheet before the trailing end of the preceding sheet is detected, with a controller managing the sheet feed unit to stop and resume feeding based on detected leading and trailing ends, ensuring continuous conveying while minimizing sheet distance and preventing jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet feed unit waits for the detector to confirm the trailing end of a sheet before feeding the next sheet, then sheet jam is prevented, but the distance between sheets increases and productivity decreases
Solution Approach 1:
The sheet feed unit starts feeding the next sheet before the detector has confirmed the trailing end of the current sheet, based on predetermined timing calculated from sheet length. This preliminary action reduces the distance between sheets and increases productivity while maintaining reliability through continuous monitoring and emergency stop capability if the trailing end is not detected by the predetermined time.
2Productivity
If the sheet feed unit starts feeding before the trailing end is detected to reduce sheet distance, then productivity improves, but sheet jam risk increases
Solution Approach 1:
The detector continuously monitors the trailing end of each sheet during the feeding process. If the trailing end is not detected by the predetermined time after the next sheet feeding starts, the controller stops the sheet feed unit to prevent sheet jam. This feedback mechanism allows the system to operate at higher speed while maintaining safety through real-time monitoring and corrective action.
3Reliability
If the sheet feed unit stops and resumes based on trailing end detection, then sheet jam is prevented, but conveying time increases
Solution Approach 1:
The sheet feed unit performs preliminary feeding before trailing end detection to minimize the waiting time between sheets. The stop and resume operations are only performed when necessary (when trailing end is not detected by predetermined time), rather than for every sheet transition. This approach significantly reduces the average conveying time while maintaining sheet jam prevention capability.
Data Source
AI summary
A sheet conveying device is configured to start feeding, before a trailing end of a preceding sheet passes a detector, a next sheet following the preceding sheet, based on a calculated sheet length. If the trailing end of the preceding sheet has not been detected by the detector when a counted value reaches a particular count value, the driving of a sheet feed unit configured to feed sheets may be stopped while a conveying unit configured to convey the sheets is continuously being driven. Subsequently, based on the detector detecting the trailing end of the preceding sheet, the driving of the sheet feed unit may be resumed.