Sheet Punching Timing Control for Productivity and Accuracy
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Solution Overview
Problem
Conventional sheet post-processing apparatuses face inefficiencies in punching time due to the need for uniform advance time periods, which do not account for varying sheet thicknesses, leading to reduced productivity and potential misalignment of punching positions.
Innovation Solution
A sheet post-processing apparatus with a moving member having a cam and reciprocating drive unit, a determination unit to identify sheet type, and a control unit that adjusts the timing of the drive unit's operation based on sheet type, allowing the moving member to start moving before sheet conveyance stops and changing its start timing accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform advance time period is used for all sheet types, then the punching system is simple to control, but productivity is reduced and punching accuracy deteriorates for thick sheets
Solution Approach 1:
The system dynamically adjusts the advance time period based on sheet thickness. The control unit receives sheet thickness information and selects different advance time periods from stored values, allowing the timing to adapt to different sheet types rather than remaining fixed. This resolves the contradiction by making the system flexible enough to maintain both high speed and accuracy for various sheet conditions.
Solution Approach 2:
The invention changes the timing parameter (advance time period) according to sheet thickness. By storing multiple advance time period values in the control unit and selecting the appropriate one based on detected sheet thickness, the system optimizes punching timing for each sheet type, thereby improving both productivity and accuracy simultaneously.
2Manufacturing precision
If the advance time period is extended to account for thick sheets, then punching accuracy is maintained, but time is wasted on plain sheets reducing productivity
Solution Approach 1:
The control unit stores multiple advance time period values corresponding to different sheet thickness ranges. When a plain sheet is detected, a shorter advance time period is selected, reducing the waiting time and accelerating the punching cycle. When a thick sheet is detected, a longer advance time period is selected to ensure accurate positioning. This parameter adaptation eliminates unnecessary time loss on plain sheets while maintaining accuracy on thick sheets.
Solution Approach 2:
The system transitions from a static, uniform advance time period to a dynamic, variable advance time period that changes based on real-time sheet thickness detection. This dynamic adjustment allows the system to optimize timing for each specific sheet, preventing time waste on plain sheets while ensuring adequate preparation time for thick sheets.
3Productivity
If the punch motor starts earlier to shorten punching time, then productivity increases, but slider overrun occurs and punching accuracy decreases
Solution Approach 1:
The system adjusts the advance time period parameter based on sheet thickness to optimize the start timing of the punch motor. For thick sheets, a longer advance time allows the slider to decelerate properly and stop at the correct position, preventing overrun. For plain sheets, a shorter advance time maximizes productivity. This parameter adaptation resolves the contradiction by finding the optimal timing for each sheet type.
Solution Approach 2:
The control unit performs preliminary determination of sheet thickness before initiating the punching operation. Based on this preliminary information, it pre-calculates and sets the appropriate advance time period, ensuring that the punch motor starts at the optimal moment. This preliminary action prevents slider overrun while maintaining high productivity by avoiding unnecessary delays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the time wasted until actual punching begins, enhancing productivity by optimizing punching timing for different sheet types and preventing slider overrun, thus improving punching accuracy and efficiency.
Implementation Method 1
a moving member configured to have a cam and reciprocate
Data Source
AI summary
A sheet post-processing apparatus which is capable of shortening time wasted until actual start of punching and enhancing productivity. A drive unit causes a moving member which has a cam and reciprocates. A punching member is driven by a movement of the cam of the moving member and punches a sheet when the moving member moves forth and moves back. A determination unit determines a type of the sheet. A control unit controls, when a sheet to be punched is to be subjected to a punching process, the drive unit such that the moving member starts moving before conveyance of the sheet to be punched stops, and controls, when the sheet to be punched is to be subjected to the punching process, the drive unit such that timing with which the moving member starts moving is changed based on the determination by the determination unit.