Tandem Image Forming System Sheet Type Switching Control
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Solution Overview
Problem
In serial tandem image forming systems, the productivity is reduced due to the need for switching operating states between different sheet types, leading to delays in sheet conveyance and potential degradation of image quality when the subsequent sheet is paused mid-process.
Innovation Solution
A controller is implemented to predict the finishing timing of switching operating states in both the upstream and downstream image forming apparatuses, allowing the subsequent sheet to standby at the registration unit and restart conveyance before the switching is complete, ensuring proper processing and minimizing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the subsequent sheet is made to stand by at the registration unit until the switching of the operating state is finished, then the image quality is maintained, but the productivity is reduced due to the longer conveyance distance and wider sheet interval
Solution Approach 1:
The controller predicts the finishing timing of the operating state switching in advance and restarts the conveyance of the subsequent sheet before the switching is actually finished. This preliminary action allows the sheet to be in motion during the switching process, reducing the waiting time and maintaining productivity while ensuring the sheet reaches the image formation process only after switching is complete.
2Loss of time
If the subsequent sheet is conveyed to an advanced position in the downstream side of the registration unit, then the conveyance distance after resumption is shortened, but the sheet may stop in the middle of the image formation process causing image quality degradation
Solution Approach 1:
The controller predicts the finishing timing of the operating state switching and restarts the conveyance of the subsequent sheet in advance, before the switching is finished. This allows the sheet to be conveyed to an advanced position without stopping during the image formation process, as the restart timing is calculated to ensure the sheet reaches the image formation area only after switching is complete.
3Productivity
If the conveyance of the subsequent sheet is restarted in advance of finishing the switching of the operating state, then the productivity is improved by reducing waiting time, but the sheet may be processed with incorrect operating state causing image quality degradation
Solution Approach 1:
The controller monitors the switching process and uses feedback to determine when the switching is actually finished. The conveyance restart is timed based on the predicted finishing timing, and the system ensures that the sheet is only processed with the correct operating state by coordinating the restart with the switching completion.
4Reliability
If the sheet conveyance is halted during operating state switching, then the correct operating state is ensured for the subsequent sheet, but the sheet interval becomes wider reducing productivity
Solution Approach 1:
Instead of halting the conveyance until switching is finished, the controller restarts the conveyance in advance of the switching completion. This preliminary restart action reduces the sheet interval and maintains productivity while the system ensures the sheet reaches the image formation process only after the operating state switching is complete.
Data Source
AI summary
A serial tandem image forming system is described which is capable of inhibiting both the degradation of image quality and the reduction of the productivity. This system consists mainly of the control units of upstream and downstream apparatuses. When a preceding sheet differs from the subsequent sheet in sheet type, a control unit for controlling the image forming system has the subsequent sheet stand by at a paper stop roller of the upstream apparatus, and performs the operation of switching the operating states of the upstream and downstream apparatuses in accordance with the sheet type of the subsequent sheet. Also, the control unit predicts the timing of finishing the switching of the operating state, and then re-starts the conveyance of the subsequent sheet, in advance of finishing the switching of the operating state, by controlling the paper stop roller on the basis of the predicted finishing timing.