Sheet Puncher Positioning for Skew Correction
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Solution Overview
Problem
Existing sheet finishing apparatuses face issues with accurately boring punch holes in skewed sheets, particularly when the sheets are tabbed, as they struggle to measure skew amounts accurately, leading to potential jams due to curled or folded corners being caught in the puncher or sensor.
Innovation Solution
A sheet finishing apparatus with a conveyance mechanism, a puncher, and detection sections to accurately position the puncher based on sheet size and speed, including first and second detection sections for leading and lateral edges, and a control section that adjusts the puncher's position to prevent jams by correcting skew and avoiding corner collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the puncher is positioned to bore holes in skewed sheets, then punching accuracy is improved, but sheet corner jams occur when sheets are curled or folded
Solution Approach 1:
The system performs preliminary detection of the sheet leading edge and lateral edge before the punching operation. The control section calculates the skew amount based on detection timing and uses this information to pre-position the puncher at appropriate locations, preventing corner jams before they occur.
Solution Approach 2:
The system uses detection sections to continuously monitor sheet position and provides feedback to the control section. The control section adjusts puncher positioning based on real-time detection of leading edge and lateral edge positions, creating a closed-loop control system that adapts to actual sheet conditions.
2Productivity
If the puncher moves to standby position after punching, then the system is ready for next sheet, but detection timing becomes critical for preventing jams
Solution Approach 1:
The system dynamically adjusts the puncher position between standby and punching positions based on real-time sheet detection. The moving mechanism enables the puncher to transition smoothly between positions while the control section continuously monitors detection timing to optimize the cycle without causing jams.
3Manufacturing precision
If multiple detection sections are used to detect leading and lateral edges, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The detection function is segmented into two specialized detection sections: one for detecting the leading edge and another for detecting the lateral edge. Each detection section focuses on a specific aspect of sheet positioning, simplifying the design of individual sensors while achieving comprehensive positioning accuracy through their combined information.
Data Source
AI summary
A sheet finishing apparatus includes a moving mechanism to move a puncher for boring punch holes in a sheet between a penetrate position and standby position, a detection section which is disposed upstream of the puncher in a sheet conveyance direction and detects a leading edge of the sheet, and a control section to control a moving mechanism based on a detection timing of the detection section and according to a size of the sheet and a movement speed of the sheet, so that a front corner of the sheet does not coincide with a position of a punching blade of the puncher when the sheet passes through the puncher.