Sheet Discharge Tray Position Control for Jam Prevention
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Solution Overview
Problem
Conventional sheet discharge devices face issues in maintaining the vertical position of the uppermost sheet on the discharge tray, leading to potential interference with subsequent sheet discharges and increased risk of paper jams, as they rely on a top-surface detection mechanism that may not accurately determine the stacking state of sheets.
Innovation Solution
The sheet discharge device incorporates an inclined discharge tray and a control section that uses a top-surface detection part to monitor the move-up time of the tray, distinguishing between normal and abnormal stacking states by measuring the time taken for the tray to reach the detection position, and executes a correction process when an abnormal state is detected, ensuring proper alignment for subsequent discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge tray is moved up until the top-surface detection part detects the sheet, then the vertical position of the uppermost sheet is maintained, but the detection accuracy of the stacking state is insufficient leading to paper jams
Solution Approach 1:
The detection process is segmented into multiple phases: initial tray position detection, sheet presence detection, and stacking state detection. Each phase uses the top-surface detection part at different operational stages to determine specific parameters, improving overall detection accuracy while maintaining reliability.
Solution Approach 2:
The discharge tray is preliminarily positioned at a predetermined position before sheet discharge begins. The control section preliminarily determines the tray's vertical position and only performs stacking state detection when the tray is at this predetermined position, ensuring accurate detection before actual sheet stacking occurs.
2Manufacturing precision
If the discharge tray is continuously moved up and down to maintain sheet position, then sheet alignment is improved, but the complexity of the control system increases
Solution Approach 1:
The control section performs periodic stacking state detection at regular intervals when the discharge tray is at the predetermined position. This periodic action ensures proper sheet alignment without requiring continuous complex control operations, simplifying the overall system while maintaining precision.
Solution Approach 2:
The system uses the existing top-surface detection part and tray movement mechanism to perform self-detection and self-correction of stacking state. The control section automatically adjusts tray position based on detection results without requiring external intervention or additional complex control mechanisms.
Data Source
AI summary
When a discharge count has exceeded a specified number of sheets, a sheet discharge device executes a process of moving down a discharge tray by a specified quantity and thereafter moving up the discharge tray until a top-surface detection part outputs a top-surface detection signal, while clocking a move-up time lasting from a move-up start of the discharge tray until output of the top-surface detection signal by the top-surface detection part. When the move-up time is equal to or less than a reference time, the sheet discharge device makes a next sheet discharged while the top-surface detection part outputs the top-surface detection signal; on the other hand, when the move-up time is more than the reference time, the sheet discharge device executes a correction process of moving down the discharge tray before making the next sheet discharged.