Sheet Conveying Device Delayed Absence Detection
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Solution Overview
Problem
In sheet conveying devices, the existing configuration often leads to premature detection of sheet absence, causing unnecessary jamming due to the proximity of sensors, which results in inefficient sheet feeding and increased jamming frequency.
Innovation Solution
The introduction of a control unit that delays the determination timing of sheet presence or absence on the placement tray by considering the lifted distance and time, ensuring sufficient time for the presence detection sensor to accurately detect sheet absence and prevent erroneous determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the next-sheet feeding sensor is provided closer to the placement tray to improve sheet feeding timing, then sheet feeding speed is improved, but the presence detection sensor cannot immediately detect sheet absence, leading to increased jamming frequency
Solution Approach 1:
The control unit performs preliminary action by delaying the determination timing of sheet absence detection. Instead of immediately determining sheet absence when the presence detection sensor detects no sheet, the control unit waits for a predetermined period to elapse. This preliminary delay prevents premature determination and reduces erroneous jamming detection, resolving the contradiction between fast sheet feeding and accurate jamming detection.
2Productivity
If the distance between next-sheet feeding sensor and presence detection sensor is shortened to improve feeding timing, then sheet feeding efficiency is improved, but false jamming detection increases
Solution Approach 1:
The control unit changes the timing parameter of sheet absence determination by introducing a predetermined delay period. This parameter change allows the system to maintain short sensor distance for high productivity while compensating for detection lag, ensuring accurate sheet absence detection and reducing false jamming detection.
3Reliability
If the presence detection sensor is positioned downstream to detect sheet presence, then sheet feeding operation can be monitored, but detection timing is delayed causing erroneous jamming determination
Solution Approach 1:
The control unit applies preliminary action by proactively delaying the determination timing of sheet absence. The control unit is configured to determine that a sheet is absent only after a predetermined period has elapsed since the presence detection sensor detected sheet absence. This preliminary delay compensates for the downstream sensor position, ensuring accurate detection without erroneous premature determination.
Data Source
AI summary
According to one embodiment, a sheet conveying device includes a placement tray, a presence detection sensor, and a control unit. The placement tray places a sheet thereon. The presence detection sensor detects the presence or absence of the sheet on the placement tray. The control unit delays a determination timing of the presence or absence of the sheet placed on the placement tray to a predetermined timing when a condition indicating that the remaining sheets placed on the placement tray are only a few is satisfied.