Sheet Load Tray Ascending-Descending Mechanism for Skew Correction
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Solution Overview
Problem
Existing sheet transport devices fail to effectively correct sheet skew before feeding, especially when ascending-descending operations are not performed, leading to misalignment issues during the feeding process.
Innovation Solution
A sheet transport device with a sheet load tray, detector, feeder, and a controller that performs ascending-descending operations to align sheets by moving the sheet load tray between the sheet feed position and a descent position, ensuring the uppermost sheet is correctly positioned at the feeder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ascending-descending operation is not performed, then the device complexity is reduced, but the sheet alignment precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing ascending-descending operations before the feeding operation to correct sheet skew. The controller causes the sheet load tray to ascend or descend one or more times before the feeder starts feeding the sheet, which preliminarily aligns the sheet at the sheet feed position, ensuring proper alignment before the actual feeding process begins.
2Manufacturing precision
If ascending-descending operation is performed, then the sheet alignment precision is improved, but the loss of time increases
Solution Approach 1:
The patent applies partial or excessive action by allowing the controller to flexibly determine the number of ascending-descending operations. The controller can cause the sheet load tray to ascend or descend one or more times based on the detected sheet state, performing just enough operations to correct the skew without unnecessary repetitions, thus balancing alignment precision with time efficiency.
3Manufacturing precision
If the sheet load tray is moved frequently, then the sheet alignment is improved, but the wear and tear on the ascend-descend unit increases
Solution Approach 1:
The patent applies feedback by using a detector to detect whether the sheet is present on the sheet load tray and determining the number of ascending-descending operations based on the detection result. The controller adjusts the number of operations according to the actual sheet state, performing operations only when necessary and avoiding unnecessary movements that would increase wear on the ascend-descend unit.
Data Source
AI summary
A sheet transport device includes a sheet load tray on which a sheet is loaded, a detector that detects whether or not the sheet exists on the sheet load tray, a feeder that feeds the sheet one-by-one from the sheet load tray, and a sheet-load-tray ascend-descend unit that moves the sheet in a sheet loading direction to set an uppermost sheet at a sheet feed position of the feeder, and a controller. In a case where the sheet is detected by the detector, the controller causes the sheet load tray to ascend or descend before the feeder starts to feed the sheet so that ascending-descending operation for moving the sheet load tray between the sheet feed position and a descent position located below the sheet feed position is performed at least once.