Sheet Standby Portion Shift Control for Stitching Alignment
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Solution Overview
Problem
Conventional sheet processing apparatuses face challenges in aligning sheet ends during stitching processing due to high image forming speeds and small sheet discharge intervals, leading to rebounding and defective stitching, especially when increasing the number of overlapped sheets for standby processing.
Innovation Solution
A sheet processing apparatus with a control unit that adjusts the shift amount and collision velocity of sheets to prevent rebounding by successively reducing the shift amount and collision velocity as sheets are conveyed to an end portion stopper, ensuring all sheets align properly during standby processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of overlapped sheets is increased to secure time for stitching processing, then stitching processing can be completed without interrupting image formation, but the sheets collide with the rear stopper at lower speed causing defective alignment
Solution Approach 1:
The invention changes the velocity parameter of sheet conveyance dynamically. By controlling the conveyance velocity to be in the range of 0.5 to 2.0 m/s, the sheets are delivered to the rear stopper at an optimal speed that prevents both rebounding (which occurs at high speeds) and failure to reach the stopper (which occurs at low speeds when many sheets are overlapped). This parameter optimization resolves the contradiction between maintaining continuous processing and ensuring alignment precision.
2Productivity
If sheets are conveyed at high speed to maintain productivity, then processing efficiency is improved, but the sheets rebound upon collision with the stopper causing alignment defects
Solution Approach 1:
The invention optimizes the conveyance velocity parameter to a specific range (0.5 to 2.0 m/s) that balances productivity and precision. This velocity is fast enough to maintain efficient processing but slow enough to prevent rebounding when sheets collide with the rear stopper, thereby resolving the contradiction between processing speed and alignment quality.
3Speed
If the sheet discharge interval is reduced to increase image forming speed, then productivity is improved, but insufficient time is available for stitching processing
Solution Approach 1:
The invention performs preliminary overlapping of sheets at the sheet standby portion before they are discharged for stitching. By pre-positioning multiple sheets in an overlapped state and controlling their conveyance velocity, the system secures the necessary stitching processing time even when the image forming speed is high and the discharge interval is short, thus resolving the contradiction between speed and processing duration.
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
Enables seamless alignment of sheet ends during stitching, preventing rebounding and ensuring high-quality stitching without interrupting image formation, even at high image forming speeds and small discharge intervals.
Implementation Method 1
due to resistance such as friction when a sheet moves on another sheet
Implementation Method 2
due to the movement in the discharge direction caused by the inertia acting to continue the movement
Data Source
AI summary
While a sheet on an intermediate processing tray is being processed, a plurality of sheets to be processed next are kept on standby by a standby portion arranged between the intermediate processing tray and a conveyance roller and a separation roller. When conveying the plurality of sheets that have been kept on standby in an overlapped state while successively shifting the sheets from each other in the sheet conveyance direction, the shift amount is successively reduced.