Sheet Conveyance Switching Control for Multi-Feed Jam Prevention
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Solution Overview
Problem
Existing sheet conveyance systems face issues with multi-feeding, leading to defects in image formation, jams, and reduced productivity due to the need to switch conveyance paths and return switching portions, which can cause sheets to get caught and result in further jams.
Innovation Solution
A sheet conveyance apparatus with a switching portion that can be controlled to guide multi-fed sheets to a third conveyance path, using multi-feeding detection and trailing-edge detection to determine the optimal time for switching the switching portion, preventing jams and ensuring smooth conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching portion is returned to the original position before the trailing edge of the multi-fed sheet passes through, then the conveyance path can be switched for normal sheets, but the second sheet may be caught between the switching portion and guide causing a jam
Solution Approach 1:
The control portion calculates the timing for returning the switching portion to the original position based on the detected amount of overlap between multi-fed sheets. This preliminary calculation ensures the switching portion returns at the precise moment the trailing edge of the second sheet passes through, preventing the sheet from being caught between the switching portion and guide while enabling timely path switching for normal sheets.
Solution Approach 2:
The system uses a multi-feeding detection portion to detect the amount of overlap between sheets and provides feedback to the control portion. This feedback mechanism allows the system to dynamically adjust the timing of the switching portion's return based on actual sheet conditions, preventing jams while maintaining efficient conveyance.
2Reliability
If the conveyance is stopped when multi-feeding is detected, then multi-fed sheets can be discharged without image formation, but productivity is reduced due to downtime
Solution Approach 1:
The system calculates the timing for path switching in advance based on the detected overlap amount, allowing the switching portion to return to its original position at the precise moment needed. This eliminates the need to stop conveyance entirely, as the system can continuously operate while dynamically adjusting path switching timing to handle multi-fed sheets appropriately.
Solution Approach 2:
The system dynamically adjusts the timing of the switching portion's return based on real-time detection of sheet overlap conditions. Instead of using a fixed stop-and-go approach, the system continuously adapts the conveyance path switching timing to match actual sheet conditions, maintaining productivity while ensuring proper handling of multi-fed sheets.
Data Source
AI summary
A sheet conveyance apparatus includes a conveyance portion, a switching portion, a multi-feeding detection portion, and a control portion. The multi-feeding detection portion disposed upstream of the switching portion in a sheet conveyance direction and detecting multi-feeding in which a first sheet and a second sheet that follows the first sheet overlap with each other. The control portion controls the switching portion for guiding the first sheet and the second sheet to the third conveyance path by switching the switching portion to the second position when multi-feeding is detected by the multi-feeding detection portion. When multi-feeding is detected by the multi-feeding detection portion, the control portion calculates a first time at which a trailing edge of the second sheet in the sheet conveyance direction has been passed through the switching portion, and switches the switching portion from the second position to the first position at the first time.