Sheet Discharge Speed Control for Jam Prevention
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Solution Overview
Problem
Existing sheet discharge apparatuses face issues with paper jams due to increased discharge resistance when the height of the uppermost sheet on the tray is lowered, leading to a larger abutting angle and buckling of sheets, especially when the tray is full or partially emptied during operation.
Innovation Solution
A sheet discharge apparatus with a control system that adjusts the discharge speed based on the height of the uppermost sheet, setting a faster speed when the sheet detection system detects a lower height position to reduce discharge resistance and prevent paper jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sheet discharge speed is increased to prevent binding portion interference, then the sheet discharge speed is improved, but the discharge resistance increases when the uppermost sheet height is lowered, causing sheet buckling and paper jams
Solution Approach 1:
The patent applies dynamics by making the sheet discharge speed variable rather than fixed. The discharge speed is dynamically adjusted based on the detected height position of the uppermost sheet on the tray. When the height position is low (indicating fewer sheets stacked), the discharge speed is reduced to prevent buckling and paper jams. When the height position is high, the discharge speed can be increased to maintain productivity. This dynamic adjustment resolves the contradiction between maintaining high discharge speed and preventing paper jams under varying sheet stack conditions.
Solution Approach 2:
The patent implements feedback control by using a sheet detection portion to continuously monitor the height position of the uppermost sheet on the tray. This detection information is fed back to the control portion, which then adjusts the sheet discharge speed accordingly. The feedback mechanism ensures that the discharge speed is always appropriate for the current sheet stack height, preventing paper jams while maintaining optimal discharge speed for productivity.
2Ease of operation
If the abutting angle becomes large due to lowered uppermost sheet height, then the sheet stacking is simplified, but the discharge resistance increases causing sheet buckling
Solution Approach 1:
The patent applies parameter changes by adjusting the discharge speed parameter based on the sheet stack height. When the uppermost sheet height is low, causing a large abutting angle, the discharge speed parameter is reduced to compensate for the increased discharge resistance. This prevents sheet buckling while allowing the large abutting angle to remain, which simplifies sheet stacking. The parameter change in discharge speed balances the trade-off between stacking ease and sheet strength.
3Productivity
If the tray is kept at home position for continuous sheet discharge, then the productivity is maintained, but the sheet bundle may interfere with the binding portion of stacked sheet bundle
Solution Approach 1:
The patent applies preliminary action by detecting the height position of the uppermost sheet before discharging the next sheet bundle. When the detection shows that the height position is high (indicating a full tray), the system preliminarily prevents discharge or adjusts the discharge speed to avoid interference with the binding portion of stacked sheet bundles. This preliminary detection and prevention mechanism maintains productivity by allowing continuous discharge when safe, while preventing harmful interference when the tray is full.
Data Source
AI summary
A sheet discharge apparatus includes a sheet stacking portion on which a sheet discharged by a discharging portion is stacked, and a control portion configured to control a moving unit such that a height position of an uppermost sheet stacked on the sheet stacking portion becomes a first height position. In a case where a sheet detection portion detects that the height position of the uppermost sheet is above a second height position, the control portion sets a sheet discharge speed of the discharging portion to a first sheet discharge speed. In a case where the sheet detection portion detects that the height position of the uppermost sheet becomes lower than the second height position, the control portion controls the sheet discharge speed to be a second sheet discharge speed faster than the first sheet discharge speed.