Sheet Finisher Roller Speed Control for Short-Run Printing
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Solution Overview
Problem
In short-run printing, existing sheet finishers face challenges in maintaining high productivity and positional accuracy due to sheet displacement caused by curved conveyance paths, which complicates the structure and increases costs, making it difficult to achieve original productivity improvement objectives.
Innovation Solution
A sheet finisher with an intermediate storing section for superposed sheets, paired conveyance rollers driven by separate motors, and a correction controller to manage rotation speed, allowing for accurate alignment and conveyance of multiple sheets without enhancing conveyance speed, thereby reducing sheet displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a curved conveyance path is used to convey superposed sheets, then sheets can be conveyed through the finisher, but sheet displacement occurs between inside and outside sheets
Solution Approach 1:
The conveyance system is segmented into multiple independent roller units, each capable of separate control. This allows different portions of the sheet stack to be conveyed independently, preventing displacement caused by curved path friction differences.
Solution Approach 2:
The conveyance method changes from a fixed curved path to a controllable roller system where rotation speeds and positions can be dynamically adjusted. This enables compensation for sheet displacement by varying conveyance parameters during the process.
2Productivity
If conveyance speed in the sheet finisher is increased to maintain space-between-sheets, then productivity improves, but sheet displacement increases due to friction in curved paths
Solution Approach 1:
The system transitions from a static curved conveyance path to a dynamic roller-based system where each roller can be independently controlled in real-time. This allows the conveyance parameters to be dynamically adjusted based on sheet position and friction conditions, maintaining accuracy at high speeds.
Solution Approach 2:
Conveyance parameters such as roller rotation speed and position are made variable and controllable, allowing optimization of both speed and accuracy by adjusting parameters according to actual sheet conditions during conveyance.
3Manufacturing precision
If alignment mechanisms such as stopper members are added to correct sheet displacement, then positional accuracy improves, but device structure becomes complicated and costs increase
Solution Approach 1:
The patent replaces complex mechanical alignment mechanisms (stopper members, alignment guides) with a controlled roller conveyance system that achieves alignment through differential rotation and friction control, simplifying the overall structure.
Solution Approach 2:
Instead of adding mechanical alignment components, the system uses parameter control (roller rotation speeds, positions, and friction characteristics) to achieve sheet alignment, reducing structural complexity while maintaining precision.
Data Source
AI summary
A sheet finisher having a post-processing section that conducts post-processing on a sheet on which an image has been formed by an image forming apparatus, the sheet finisher comprising: an intermediate storing section in which a plurality of sheets conveyed from the image forming apparatus are superposed to be stored temporarily; a pair of conveyance rollers that convey the plurality of sheets stored in the intermediate storing section to the post-processing section while the plurality of sheets are superposed; each of two drive motors which drives one of the pair of conveyance rollers that comes in contact with one sheet of the plurality of sheets and the other of the pair of conveyance rollers that comes in contact with the other sheet of the plurality of sheets, separately; and a correction controller that controls a rotation speed of at least one of the two drive motors.