Switchback Roller Control for Paper Sheet Jam Prevention
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Solution Overview
Problem
Existing paper sheet processing apparatuses face issues with paper jams due to inconsistent stopping and reorientation of paper sheets during the switchback process, leading to misalignment and further jamming, especially when sheets are stopped before reaching the switchback section or when their rear end has passed the detection sensor.
Innovation Solution
The apparatus incorporates a detection section and control system that monitors the paper sheet's position and orientation, ensuring it is stopped and reoriented correctly before switching directions, using sensors and a kick lever to prevent jams by controlling the switchback roller's rotation and conveyance paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switchback roller is stopped at an appropriate time based on sensor detection, then the paper sheet can be stopped and conveyed backwards, but the paper sheet may be stopped too early or too late causing misalignment and paper jams
Solution Approach 1:
The detection section detects the rear end of the paper sheet in advance before it reaches the switchback section, allowing the control section to stop the conveyance at the optimal moment. This preliminary detection ensures the paper sheet is stopped at the correct position rather than too early or too late, preventing misalignment and paper jams during the switchback process
Solution Approach 2:
The detection section continuously monitors the paper sheet position and provides feedback to the control section. Based on this feedback, the control section adjusts the stopping timing dynamically, ensuring the paper sheet is stopped at the precise moment when its rear end can be properly oriented to the second conveyance path, thereby improving both reliability and positioning accuracy
2Productivity
If the paper sheet is conveyed again after being stopped, then processing can continue, but the paper sheet may be unnecessarily fed into the switchback section causing buckling and jam
Solution Approach 1:
The detection section performs preliminary detection to identify paper sheets that require switching back before they are unnecessarily fed into the switchback section. This allows the control section to prevent buckling and jamming by ensuring only appropriately positioned sheets are conveyed backwards, maintaining both productivity and reliability
Solution Approach 2:
The detection section provides continuous feedback on paper sheet position and status to the control section. This feedback mechanism ensures that when paper sheets are conveyed again after stopping, the system can distinguish between sheets that need switching back and those that should not, preventing unnecessary switchback operations that cause buckling and jam
3Measurement precision
If the sensor detects the rear end of the paper sheet, then the switchback roller can be stopped, but the paper sheet may not be oriented correctly after switchback
Solution Approach 1:
The detection section detects the rear end of the paper sheet in advance to determine the optimal stopping moment. This preliminary detection, combined with the kick lever mechanism, ensures that when the paper sheet is stopped and conveyed backwards, it is properly oriented to the second conveyance path, achieving both position and orientation precision
Solution Approach 2:
The kick lever acts as an intermediary mechanism between the detection section and the paper sheet orientation. It receives the detection signal and mechanically ensures proper orientation of the paper sheet rear end to the second conveyance path, bridging the gap between detection precision and orientation precision
Data Source
AI summary
A switchback unit has a switchback roller which receives a paper sheet conveyed in a first direction into a nip for forward rotation and backwardly rotates the paper sheet after stopping the paper sheet to feed the paper sheet to a second conveyance path. When the conveyance of the paper sheet stopped on the way to the switchback section is resumed, control is performed so that the switchback roller is forwardly rotated until a sensor detects the tip of the paper sheet, and then the switchback roller is stopped and backwardly rotated.