Post-Processing Apparatus Over-Stacking Detection
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Solution Overview
Problem
Existing post-processing apparatuses struggle to accurately determine over-stacking of sheets, especially with special sheets having large basis weights, leading to potential tray failures and malfunctions due to incorrect detection methods based on sheet height or number after power changes.
Innovation Solution
A post-processing apparatus equipped with a stacking tray, sheet detector, and controller that executes first and second determination processes to assess over-stacking, using both sheet number and height detection, with stored results preventing additional stacking when over-stacking is detected, and utilizing nonvolatile memory to maintain information during power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If over-stacking determination is made based on sheet height, then normal sheets can be properly monitored, but special sheets with large basis weight cannot be accurately detected and may cause tray overload
Solution Approach 1:
The over-stacking detection method is segmented into two independent determination processes: height-based determination for normal sheets and number-based determination for special sheets. This segmentation allows each method to be optimized for its specific sheet type, resolving the contradiction between measurement precision for normal sheets and adaptability to special sheets.
Solution Approach 2:
The system dynamically selects which determination process to execute based on sheet type identification. The controller switches between height-based and number-based determination methods according to the detected sheet characteristics, enabling the system to adapt to different sheet types while maintaining accurate over-stacking detection.
2Reliability
If upper limit number of stacked sheets is suppressed to a small value to prevent tray overload, then special sheets can be protected, but normal operation is restricted and productivity decreases
Solution Approach 1:
Different upper limit values are applied locally to different sheet types. The system uses a first upper limit number for special sheets with large basis weight and a second upper limit number for normal sheets. This local differentiation allows the system to maintain safety for special sheets while preserving productivity for normal sheet operation.
Solution Approach 2:
The system changes the determination parameter from a unified small upper limit number to type-specific upper limit numbers. By adjusting the parameter (upper limit value) based on sheet type, the system achieves both safety for special sheets and adequate capacity for normal sheets.
3Measurement precision
If over-stacking determination is reset when power is turned on, then erroneous detection is prevented, but over-stacking state is lost and safety cannot be maintained
Solution Approach 1:
The controller performs preliminary determination processes at power-on to establish the correct over-stacking state before normal operation resumes. This preliminary action ensures that any persistent sheets from previous operations are properly accounted for, preventing both erroneous detection and loss of safety information.
Solution Approach 2:
The system uses feedback from the sheet detector and counter to continuously monitor and update the over-stacking state. This feedback mechanism ensures that the determination result is maintained even after power cycles, as the system can detect and respond to the actual physical state of the stacking tray.
4Reliability
If only number-based determination is used for special sheets, then tray overload can be prevented, but height-based detection capability is wasted and system complexity increases
Solution Approach 1:
The controller is designed with multi-functionality to handle both height-based and number-based determination processes. This universal design allows a single system to accommodate different sheet types and detection methods without requiring separate dedicated systems, managing complexity through integrated control.
Data Source
AI summary
To prevent sheets from being allowed to be delivered after activation of a system when over-stacking has been detected before the activation of the system, a post-processing apparatus includes a stacking tray configured to allow sheets subjected to predetermined processing to be stacked thereon. The post-processing apparatus determines whether or not additional sheets are allowed to be stacked onto the stacking tray based on the number of sheets stacked on the stacking tray. The determination result indicating that the additional sheets are prohibited to be stacked onto the stacking tray is stored in a nonvolatile RAM. The post-processing apparatus determines, after being activated, whether or not the determination result is stored in the nonvolatile RAM, and determines that the additional sheets are prohibited to be stacked onto the stacking tray when the determination result is stored in the nonvolatile RAM.