Rotating Paddle Sheet Stacking Alignment
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Solution Overview
Problem
Conventional sheet processing apparatuses face challenges in aligning and stacking sheets of varying sizes and types, particularly thin papers, due to differences in sheet stiffness and inertial forces, leading to misalignment, buckling, and reduced productivity, especially under different environmental conditions.
Innovation Solution
A sheet processing apparatus with a rotating member that applies a force to discharged sheets, rotating at two distinct speeds to align and stack sheets effectively, with one speed for dropping sheets onto a stacking portion and a slower speed for abutting against a regulating portion, ensuring proper alignment and handling regardless of sheet type or environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the return paddle rotates at high speed (700-800 mm/s) to handle large mass sheets, then large sheets can be conveyed effectively, but thin papers may buckle when abutted against the trailing end stopper
Solution Approach 1:
The return paddle's rotation speed is dynamically adjusted based on sheet characteristics. The control unit varies the rotation speed between a first speed (higher) for sheets requiring greater conveying force and a second speed (lower) for thin papers prone to buckling, optimizing both conveying effectiveness and alignment precision for different sheet types
Solution Approach 2:
The system changes the operational parameter (rotation speed) of the return paddle according to sheet properties. By detecting sheet characteristics and adjusting the rotation speed parameter accordingly, the system adapts the conveying force to match the sheet's mass and stiffness, preventing buckling while maintaining effective alignment
2Productivity
If the return paddle rotates faster to complete two rotations during short discharge intervals, then productivity increases, but denting and folding occur at the trailing end of sheets
Solution Approach 1:
The return paddle's rotation speed is dynamically controlled to vary during operation. The system uses different rotation speeds for different phases of the alignment process and for different sheet types, allowing high-speed operation for productivity when appropriate while using lower speeds to prevent denting and folding during critical alignment phases
Solution Approach 2:
The system employs periodic variation in rotation speed patterns. By alternating between different rotation speeds and rotation counts (one or two rotations) based on sheet discharge intervals and sheet characteristics, the system maintains high productivity while preventing sheet damage through controlled periodic action
3Manufacturing precision
If the return paddle rotates one rotation for small sheets, then alignment is achieved, but large sheets cannot be returned to the trailing end stopper
Solution Approach 1:
The number of rotations and rotation speed of the return paddle are dynamically adjusted based on sheet size. The control unit determines whether one or two rotations are needed and sets the appropriate rotation speed, enabling the system to adapt to various sheet sizes from small A4 to large A3 and beyond, maintaining alignment precision across all sizes
Solution Approach 2:
The return paddle system is designed to perform multiple functions across different sheet sizes. By varying the rotation count and speed, a single return paddle mechanism handles both small sheets (one rotation) and large sheets (two rotations), achieving universal applicability across diverse sheet dimensions while maintaining effective alignment
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 improves aligning, stacking, and discharge productivity across various sheet sizes and types, minimizing misalignment and buckling, and adapts to different environmental conditions, enhancing overall sheet processing efficiency.
Implementation Method 1
a sheet with a large mass like a large size sheet (namely, a sheet having a large inertial force) is required to be returned by a large conveying force
Implementation Method 2
When the mass of the sheet is large, the conveying force of the sheet is increased by increasing the rotation number of the paddle
Data Source
AI summary
The present invention provides a sheet stacking apparatus which has a pair of lower discharge rollers which discharges a sheet, a processing tray which stacks the sheet discharged from the pair of lower discharge rollers, a trailing end stopper which aligns the trailing end portion in the conveying direction of the sheet bundle stacked on the processing tray, and pull-in paddles which drop the sheet discharged from the pair of lower discharge rollers on the processing tray and conveys the sheet to abut against the trailing end stopper where the pull-in paddles rotate at a first rotating speed so that the sheet discharged from the pair of lower discharge rollers is dropped on the processing tray and the pull-in paddles rotate at a second rotating speed, slower than the first rotating speed, so that the sheet abuts against the trailing end stopper.